Redondo Apraiz, Jose Manuel
Total activity: 472
Expertise
Applied Physics, Environmental Fluid Dynamics, Fractals, Mixing, Non-Linear Physics, Swimming, Thermoelectricity, Turbulence
h index
21
Professional category
College professor
Doctoral courses
Doctor en Ciencias Fisicas
PhD in Applied Mathematics
University degree
Ciencias Fisicas
Research group
DF - Nonlinear Fluid Dynamics
Department
Department of Applied Physics
School
Barcelona School of Building Construction (EPSEB)
E-mail
redondofa.upc.edu
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    Application of multifractal analysis to the study of SAR features and oil spills on the ocean surface  Open access

     Tarquis Alfonso, Ana Maria; Platonov, A.; Matulka, Anna Magdalena; Grau, J.; Sekula, Emil; Diez, M.; Redondo Apraiz, Jose Manuel
    Nonlinear processes in geophysics
    Date of publication: 2014-01-01
    Journal article

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    The use of synthetic aperture radar (SAR) to investigate the ocean surface provides a wealth of useful information that is very seldom used to its full potential. Here we will discuss the application of multifractal techniques to detect oil spills and the dynamic state of the sea regarding turbulent diffusion. We present different techniques in order to relate the shape of the multifractal spectral functions and the maximum fractal dimension to the behaviour of the ocean surface. We compare eddy and sheared dominated flows with convective driven flows and discuss the different features and observation methods. We also compare the scaling of different oil spills detected by means of SAR images. Recent spills and weathered ones are selected and compared to investigate their behaviour in different spatial and temporal ranges. We calculate the partition function based on the grey intensity value of each SAR pixel deriving several types of multifractal spectra as a function of spill residence time estimated for each image. Image manipulations are seen to reduce the speckle noise and thus distinguish much better the texture of the oil spill images. The results are used to discuss how eddy diffusivity may be estimated and used in a description of the ocean surface using a simple turbulence kinematic simulation model to predict the shape of oil spills. Differences in the multifractal spectrum among SAR images may detect the slicks due to plankton and also provide information on the age of the oil spills, on the Lagrangian turbulent structure and on ocean surface diffusivity.

    The use of synthetic aperture radar (SAR) to investigate the ocean surface provides a wealth of useful information that is very seldom used to its full potential. Here we will discuss the application of multifractal techniques to detect oil spills and the dynamic state of the sea regarding turbulent diffusion. We present different techniques in order to relate the shape of the multifractal spectral functions and the maximum fractal dimension to the behaviour of the ocean surface. We compare eddy and sheared dominated flows with convective driven flows and discuss the different features and observation methods. We also compare the scaling of different oil spills detected by means of SAR images. Recent spills and weathered ones are selected and compared to investigate their behaviour in different spatial and temporal ranges. We calculate the partition function based on the grey intensity value of each SAR pixel deriving several types of multifractal spectra as a function of spill residence time estimated for each image. Image manipulations are seen to reduce the speckle noise and thus distinguish much better the texture of the oil spill images. The results are used to discuss how eddy diffusivity may be estimated and used in a description of the ocean surface using a simple turbulence kinematic simulation model to predict the shape of oil spills. Differences in the multifractal spectrum among SAR images may detect the slicks due to plankton and also provide information on the age of the oil spills, on the Lagrangian turbulent structure and on ocean surface diffusivity.

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    On the entrainment coefficient in a forced plume: quantitative effects of source parameter  Open access

     Matulka, Anna Magdalena; Lopez Gonzalez-Nieto, Pilar; Redondo Apraiz, Jose Manuel; Tarquis Alfonso, Ana Maria
    Nonlinear processes in geophysics
    Date of publication: 2014-02-24
    Journal article

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    The behavior of a forced plume is mainly controlled by the source buoyancy and momentum fluxes and the efficiency of turbulent mixing between the plume and the ambient fluid (stratified or not). The interaction between the plume and the ambient fluid controls the plume dynamics and is usually represented by the entrainment coefficient aE. Commonly used one-dimensional models incorporating a constant entrainment coefficient are fundamental and very useful for predictions in geophysical flows and industrial situations. Nevertheless, if the basic geometry of the flow changes, or the type of source or the environmental fluid conditions (e.g., level of turbulence, shear, ambient stratification, presence of internal waves), new models allowing for variable entrainment are necessary. The presented paper is an experimental study based on a set of turbulent plume experiments in a calm unstratified ambient fluid under different source conditions (represented by different buoyancy and momentum fluxes). The main result is that the entrainment coefficient is not a constant and clearly varies in time within the same plume independently of the buoyancy and the source position. This paper also analyzes the influence of the source conditions on the mentioned time evolution. The measured entrainment coefficient aE has considerable variability. It ranges between 0.26 and 0.9 for variable Atwood number experiments and between 0.16 and 0.55 for variable source position experiments. As is observed, values are greater than the traditional standard value of Morton et al. (1956) for plumes and jets, which is about 0.13

    The behavior of a forced plume is mainly controlled by the source buoyancy and momentum fluxes and the efficiency of turbulent mixing between the plume and the ambient fluid (stratified or not). The interaction between the plume and the ambient fluid controls the plume dynamics and is usually represented by the entrainment coefficient aE. Commonly used one-dimensional models incorporating a constant entrainment coefficient are fundamental and very useful for predictions in geophysical flows and industrial situations. Nevertheless, if the basic geometry of the flow changes, or the type of source or the environmental fluid conditions (e.g., level of turbulence, shear, ambient stratification, presence of internal waves), new models allowing for variable entrainment are necessary. The presented paper is an experimental study based on a set of turbulent plume experiments in a calm unstratified ambient fluid under different source conditions (represented by different buoyancy and momentum fluxes). The main result is that the entrainment coefficient is not a constant and clearly varies in time within the same plume independently of the buoyancy and the source position. This paper also analyzes the influence of the source conditions on the mentioned time evolution. The measured entrainment coefficient aE has considerable variability. It ranges between 0.26 and 0.9 for variable Atwood number experiments and between 0.16 and 0.55 for variable source position experiments. As is observed, values are greater than the traditional standard value of Morton et al. (1956) for plumes and jets, which is about 0.13

  • Observation of the thermocapillary motion of a droplet in a laser beam

     Lopez, Pilar; Redondo Apraiz, Jose Manuel; Ryazantsev, Yuri S.; Garcia Velarde, Manuel; González Rubio, Ramón; Ortega Gómez, Francisco
    Date of publication: 2013-06-01
    Book chapter

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    In this Chapter we report on an experimental study of the thermocapillary motion of an aniline drop in an stably stratified fluid system and driven by a laser beam. The thermocapillary motion of drops is the result of the temperature dependence of the interfacial tension. If the surface of the drop is not isothermal gradients of the surface tension appear, which in some cases can move the drop. The source of the no uniformity of the temperature of the surface can be, in particular, the heating of the drop by a laser beam. In the last years, the thermocapillary movement of bubbles and drops under the influence of laser radiation was studied theoretically and experimentally. However, in the literature there is no data on observation of the movement of a single drop in a laser beam. In this paper an experimental methodology is proposed to study such a motion of a drop.

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    Percolation experiments in complex fractal media  Open access

     Redondo Apraiz, Jose Manuel; Tarquis Alfonso, Ana Maria; Cherubini, Claudia; Lopez Gonzalez-Nieto, Pilar; Vila, Teresa
    European Geosciences Union General Assembly
    Presentation's date: 2013-04-12
    Presentation of work at congresses

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    Series of flow percolation experiments under gravity were performed in different glass model and real karstic media samples. We present a multifractal characterization of the experiments in several parametric non-dimensional flow descriptors. Using the maximum local multifractal dimension as an additional flow indicator. Also experiments on Non laminar flow and transport conditions in fractured and karstified media were performed at Bari. The investigation on hypothesis of non linear flow and non fickian transport in fractured aquifers led to a distinction on the different role of channels and microchannels and of the presence of vortices and eddy trapping. The dominance of the elongated channels produced early arrival times, with the solute traveling along the high velocity channel network. On the other hand in a lumped structured karstic media, the percolation flow produced long tails with local Eddy mixing, entrapment in eddies, and slow flow out of the eddies.

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    SAR measurements of coastal features in the NW Mediterranean  Open access

     Redondo Apraiz, Jose Manuel; Martinez Benjamin, Juan Jose; Diez Rilova, Margarita; Lopez Gonzalez-Nieto, Pilar
    European Geosciences Union General Assembly
    Presentation's date: 2013-04-12
    Presentation of work at congresses

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    The Synthetic Aperture Radar (SAR) is a useful tool to study both marine water dynamics and its pollution, this is relevant near the coastline, where river pollution may be also important. Oil spills and natural slicks are detected with SAR to reveal river and vessel pollution as well as the complex eddy and current interaction in the ocean surface near the coastline. In the framework of the ESA and European Union contracts, more than 1000 SAR images of the North-west Mediterranean Sea area taken between December 1996 and December 2008 are presented using self-similar traces that may be used to parametrize mixing at both limits of the Rossby Deformation Radius scale. Results show the ability to identify different SAR signatures and at the same time provide calibrations for the different local configurations of vortices, spirals, oil spills and tensioactive slicks that eventually allow predicting the behaviour of different tracers and pollutants in the NW Mediterranean Sea.

  • Informe Termoelectricidad BEROTZA : fractal aspects

     Redondo Apraiz, Jose Manuel
    Date: 2013-10-17
    Report

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    We present a description and some applications of the basic relationships that may affect the figure of merit in complex multiscale thermoelectric materials. The success of Onsager¿s Linear relationships between Fluxes and Forces in explaining the reversible Thermoelectric effects and in deriving Kelvin¿s relationships (Onsager 1931) has been extended to include Magneto-Thermo- Electrical effects. Nerst or Nerst-Ettinghausen Effects, among others provide further examples of possible applications in thermal technologies. The way in which the material structure is built with a controllable multifractal aspect, alternating at many different scales the grains which, either due to intrinsic cristaline anisotropy or due to a selective doping produce power relationships between the interfacial line lengths and the areas in 2D, or beween the area of the surface separating subsets of different material properties and the volumes of the respective grains in 3D. The application of these fractal aspects in order to describe fluxes that may be very different when measured at different scales may also be stated in terms of the relationships between fluxes and forces or between fluxes per unit area and gradients perpendicular to that same area. When basic physical properties that are defined in a very different geometrical way, such as masic properties or surface properties, the need of integrating over all possible scales arises in order to avoid singularities in the theory. The effect of minimum and maximum grain size clusters and their geometrical self similarity is studied in terms of non-linear relationships and of higher order cumulants for several of the Magneto-Thermo-Electric (Devies 1952) and Thermo-electric Effects

  • Mixing efficiency in buoyant flows

     Redondo Apraiz, Jose Manuel; Lopez Gonzalez-Nieto, Pilar; Diez Rilova, Margarita
    Date of publication: 2012-02-15
    Book chapter

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  • Swimming propulsion due to vortices

     Redondo Apraiz, Jose Manuel; Arellano, Raul; Carrillo Cortes, Jose Alejandro; Matulka, Annia; Ben Mahjoub Akalay, Otman; Sekula, Emil
    Date of publication: 2012-02-15
    Book chapter

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    Postprint (author’s final draft)

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    Fractal approach of turbulent dispersion  Open access

     Redondo Apraiz, Jose Manuel
    Journées Scientifiques de l'Université du Sud Toulon-Var
    Presentation's date: 2012-04-18
    Presentation of work at congresses

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    There are several techniques suitable for measuring and modelling dispersion from scalar or velocity-field measurements in a turbulent flow. Each of these has peculiar features and sometimes, even different scaling, and a careful choice has to be made depending on the kind of information available and needed. A useful way to investigate diffusion is to make use of the fractal and multifractal information that ocean and atmospheric flows provide. Here we present some fractal based techniques, where the velocity and scalar fields are related to the spectral spatial information that they provide and are used to predict diffusivity and mixing.In addition an Eulerian description can be obtained by interpolation from Lagrangian information, which is much easier to model via Kinematic Simulation or synthetic turbulence type models, because the detail velocity field is eventually sampled in a random statistical way in the whole domain during their time evolution. It is not possible to get reliable Lagrangian information using PIV since the transformation from the Eulerian description to the Lagrangian one implies an integration in time of the velocity field, especially when considering phenomena that show high sensitivity to initial conditions (turbulent flows). We show some examples of oil spill dispersion in the ocean surface and discuss several multifractal and scaling approaches.

    There are several techniques suitable for measuring and modelling dispersion from scalar or velocity-field measurements in a turbulent flow. Each of these has peculiar features and sometimes, even different scaling, and a careful choice has to be made depending on the kind of information available and needed. A useful way to investigate diffusion is to make use of the fractal and multifractal information that ocean and atmospheric flows provide. Here we present some fractal based techniques, where the velocity and scalar fields are related to the spectral spatial information that they provide and are used to predict diffusivity and mixing.In addition an Eulerian description can be obtained by interpolation from Lagrangian information, which is much easier to model via Kinematic Simulation or synthetic turbulence type models, because the detail velocity field is eventually sampled in a random statistical way in the whole domain during their time evolution. It is not possible to get reliable Lagrangian information using PIV since the transformation from the Eulerian description to the Lagrangian one implies an integration in time of the velocity field, especially when considering phenomena that show high sensitivity to initial conditions (turbulent flows). We show some examples of oil spill dispersion in the ocean surface and discuss several multifractal and scaling approaches.

  • A turbulent plume under different experimental conditions: entrainment, veolocity and vorticity fields

     Lopez Gonzalez-Nieto, Pilar; Matulka, Anna Magdalena; Redondo Apraiz, Jose Manuel; Tarquis Alfonso, Ana Maria
    International workshop on nonlinear processes in oceanic and atmospheric flows
    Presentation's date: 2012-06-01
    Presentation of work at congresses

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    Turbulent plumes are fluid motions whose primary source of kinetic energy and momentum flux is body forces derived from density inhomogeneities. The plume boundary acts as a phase boundary across which ambient fluid is entrained. The difference between the plume-fluid radial velocity and the total fluid velocity quantifies in a natural way the purely horizontal entrainment flux of ambient fluid into the plume across the phase boundary at the plume edge. At geophysics, it is usual the generation of turbulent plumes as a part of a dispersion process. For example, there are eruptionc plumes, river plumes (into a lake, sea or ocean), mantle plumes, hydrothermal plumes or contaminant plumes, for example. They also are important in engineering (building ventilation processes).

  • New approaches in modeling multiphase flows and dispersion in turbulence, fractal methods and synthetic turbulence

    Date of publication: 2012-01-01
    Book

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    This book series is a collection of the main contributions from the first five workshops held by Ercoftac Special Interest Group on Synthetic Turbulence Models (SIG42), a summary of each workshop can be found in Ercoftac Bulletin, Synthetic turbulence can model diffusion , and was simulated on a one dimensional grid with a random velocity field. Kraichnan continued with a random flow field in three dimensions, and constructed an isotropically random sum of unsteady Fourier waves with distributed frequencies. Most of the applications really started with what was to be called Kinematic Simulation (KS). Kinematic simulation are perhaps the best known of the synthetic turbulence models. They are based on a simplified incompressible velocity field which kinematically simulates the Eulerian velocity field and is generated as a sum of random incompressible Fourier modes with a given wavenumber-energy spectrum. More generally by synthetic turbulence models we mean Lagrangian models for turbulent diffusion which simulate the Lagrangian statistics that would arise from the underlying Eulerian field. Synthetic turbulence has been used as an approach to understand the general mechanisms of turbulent diffusion, but also to make quantitative predictions of relative dispersion and higher order statistical moments. While remaining as simple a model as possible, synthetic turbulence models are expected to capture the essence rather than the details of the bigger picture, synthetic turbulence models have now moved from simple to more complex flows, some are discussed in contributions herein, KS for stratified and rotating flows and other complex turbulent flow Angilella, J.R., Nicolleau, F., Redondo, J.-M.: Synthetic Turbulence Model and Particle-Laden Flows, Ecole de Géologie, Nancy, France. ERCOFTAC Bull. 79, 32¿35 (2009) Redondo, J.-M., Nicolleau, F., Cambon, C.: Synthetic Turbulence Models II, SIG 42 and 35 ERCOFTAC Workshop. ERCOFTAC Bull. 77, 5¿7 (2008)

  • Caracterización de la dispersión de contaminantes en la zona costera  Open access

     Diez Rilova, Margarita
    Defense's date: 2012-05-07
    Department of Hydraulic, Maritime and Environmental Engineering, Universitat Politècnica de Catalunya
    Theses

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    En nuestra sociedad los derivados del petróleo son la fuente principal de energía. Los accidentes con hidrocarburos han protagonizado episodios de contaminación trágicos para la biosfera del océano. Se analizan algunos de ellos, sus efectos y sistemas de limpieza. La complejidad de los procesos físicos, químicos o biológicos que actúan sobre el crudo en el mar, hacen difícil su estudio en laboratorio. Para ello se hacen numerosas campañas de campo con distintas escalas y procesos físicos predominantes diferentes: zonas costeras (Delta del Ebro y playa de Vilanova); en aguas confinadas (puerto de Barcelona y puerto de Recife); y en aguas abiertas (Mediterráneo Occidental), con diferentes tecnologías (foto, vídeo, satélite), para seguir trazadores eularianos (manchas de leche y fluoresceína, flotantes o hidrocarburos) y lagrangianos (boyas lastradas), se miden los agentes forzadores: viento, oleaje, marea, etc. y se correlacionan para caracterizar los diferentes escenarios. También se revisa el estado del arte. El tratamiento digital de imágenes de vídeo permite numerosas aplicaciones en el campo de la hidromorfodinámica, pues es posible controlar la evolución espacial y temporal de cualquier parámetro con evidencias visibles y es una técnica no intrusiva que ofrece datos de oleaje de una zona, en contraposición a los datos puntuales de los sensores. Las imágenes sufren numerosas alteraciones, deformaciones, ruidos, etc., que hay que depurar previamente. Los coeficientes de difusión presentan una gran variedad condicionada a la dependencia característica con la escala temporal y espacial de los fenómenos predominantes. Los coeficientes de difusión medidos se agruparon según el número de Reynolds y se hizo una clasificación: hipodifusividad, hiperdifusividad y difusión anómala. Esta caracterización de escenarios permite parametrizar el medio para modelizar su comportamiento y poder predecir su evolución. En el campo del oleaje se pueden obtener espectros de energía y otros parámetros para su caracterización, detectar la morfología de barras sumergidas, identificar corrientes de retorno, caracterizar run-up, etc. En el puerto de Barcelona se tomaron numerosos datos de velocidades de viento (Vv) y corriente (Vc) llegando a una buena correlación entre ambas (Vcx (cm/s)= 2.306 Vvx (m/s)+ 0.148) y constatando que hay una influencia de otros efectos como la marea, reflexión de los muelles o difracción que no se pueden obviar. Las imágenes de Rádar de Apertura sintética SAR permiten detectar episodios de contaminación y analizar la vorticidad a gran escala del medio. Resultó sorprendente el gran número de manchas detectadas. Se comprobó que los vertidos siguen la Ley de Zipp (distribución hiperbólica entre los accidentes y su tamaño). Se vió que los remolinos siguen la dirección de los cañones submarinos. Con el análisis fractal y multifractal del contorno de la mancha se puede caracterizar su origen (antropogénico o natural como masas de plankton) y su envejecimiento o persistencia, etc. Se comprueba que es posible que la intermitencia de la turbulencia pueda parametrizarse mediante medidas fractales y que el uso de momentos de orden superior ayuda a comparar medidas de difusión a distintas escalas mediante la Ley de Richardson Generalizada. Así se relaciona la pendiente del espectro, la intermitencia y la dependencia temporal de la difusión efectiva. Los distintos agentes que producen difusión en el mar sufren interacciones no-lineales complejas. Con todo ello, se pretende contribuir a comprender mejor los procesos de dispersión de los contaminantes en el mar y, por consiguiente, ayudar en la lucha contra este fenómeno.

    In our society the derivatives of petroleum are the main source of energy. The accidents with hydrocarbons have carried out tragic episodes of contamination for the biosphere of the ocean. Some of them, their effects and systems of cleaning are analyzed. The complexity of the physical, chemical or biological processes that act on the oil in the sea, makes their study in laboratory difficult. For it numerous campaigns of field with different scales and different predominant physical processes become: coastal zones (Delta of the Ebro and beach of Vilanova); in confined waters (port of Barcelona and port of Recife); and in open waters (West Mediterranean), with different technologies (photo, video, satellite), to follow Lagrangian tracers (milk spots and fluoresceine, floating or hydrocarbons) and Euler tracers (ballasted buoys), to measure the agents: wind, waves, tide, etc. and they are correlated to characterize the different scenes. Also the state-of-the-art is reviewed. Treatment digital of images of video allows many applications in field of hydromorfodynamics, because it is possible to control the space and temporary evolution of any parameter with visible evidences and is a nonintrusive technique that offers data of a zone, in contrast to the pointing data of the sensors. The images put up with numerous alterations, deformations, noises, etc., that have to purify previously. The diffusion coefficients present/display a great conditional variety to the dependency characteristic with the temporary and space scale of the main phenomena. The measured coefficients of diffusion were grouped according to the Reynolds number and a classification became: hypo-diffusion, hyper-diffusion and anomalous diffusion. This characterization of scenes allows obtaining the waves parameters, the average one to model its behavior and power to predict its evolution. In the field of the waves run-up, etc. can be obtained spectra of energy and other parameters for their characterization, the morphology of submerged bars, identification of return currents. In the port of Barcelona numerous speed data of wind (Vv) and current were taken (Vc) arriving at a good correlation between both (Vcx (cm/s) = 2,306 Vvx (m/s) + 0,148) and stating that an influence of other effects are as the tide, reflection of the wharves or diffraction that cannot be avoided. The images of Radar of synthetic Opening SAR allow to detect episodes of contamination and to analyze the vorticity on great scale of means. Was surprising the great number of spots identifies. It was verified that the spills follow the Law of Zipp (hyperbolic distribution between the accidents and their size). Saw that the eddies follow the direction of the submarine tubes. With the analysis fractal and multifractal of the contour of the spot it is possible to be characterized its origin (human or natural like masses of plankton) and its aging or persistence, etc. It is verified that it is possible that the intermitency of the turbulence can obtain parameters by means of measures fractals and that the use of moments of superior order aid to compare measures of diffusion on different scales by means of the Generalized Law of Richardson. Thus it is related the slope of the phantom, the intermitency and the temporary dependency of the effective diffusion. The different agents who produce diffusion in the sea undergo complex not-linear interactions. It, is tried yet to contribute to include/understand better the

  • Detection of waves and vortices in North Western Mediterranean

     Fraunie, Philippe; Redondo Apraiz, Jose Manuel; Matulka, Anna Magdalena
    Geophysical research abstracts
    Date of publication: 2011-04-03
    Journal article

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  • Application of the CORMIX model to assess environmental impact in the coastal area: an example of the ocean disposal system for sanitary sewers in the city of Fortaleza (Ceará, Brazil)

     Maia, L. P.; Bezerra Menezes, Maria Ozilea; Pinheiro, L.; Redondo Apraiz, Jose Manuel
    Journal of coastal research
    Date of publication: 2011-05-01
    Journal article

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    Cornell Mixing Zone Expert System-CORMIX software was used to simulate the behavior of effluents discharged by the underwater emissary in Fortaleza (Ceará, Brazil). This software is used to analyze and predict the discharge design in bodies of water. Application of the CORMIX model was determined to simulate the tracer discharge using local environmental parameters and underwater emissary discharge data. Data on wind, current and position in relation to the coast were used in the chosen case to obtain the discharge flow classification from the model since the hydrodynamic dispersion fields are differentiated by the predominance of different physical processes responsible for the dispersion and mixture of effluents. The simulations carried out considering the characteristics of the underwater emissary, liquid effluents and receiving medium show a very high dilution capacity. The dilution is directly related to coastal current speed ranging between 1:45 and 1:278, respectively the minimum and maximum for the mixture’s initial zone dilution, with diffuser distances between 16 and 55 meters. This gives the system the characteristic of good dilution capacity compared to other installed systems. At the limit of the simulations, 5.000 m from the diffuser, dilutions reached values between X1:251 and 1:2.688. From the simulations, it is possible to observe that given the difference in density between the effluent (freshwater) and the sea, the plume presents strong positive buoyancy. Thus, if we consider the unfavorable speeds and currents (0,25-direction and 0,04 - speed) we would have a P = 0,25 x 0,04 or P =0,01 (1%) probability of occurrence. However, for the actual situation, this probability is near zero. The results obtained from using the CORMIX model helped in the environmental monitoring of the effluent disposal area.

  • Time evolution of the fractal dimension in turbulent plumes

     Tarquis Alfonso, Ana Maria; Lopez Gonzalez-Nieto, Pilar; Redondo Apraiz, Jose Manuel
    Geophysical research abstracts
    Date of publication: 2011-04-03
    Journal article

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  • Multiscale analysis of SAR and ASAR river plumes and coastal features

     Redondo Apraiz, Jose Manuel; Sekula, Emil; Martinez Benjamin, Juan Jose
    International Workshop on Science and Applications of SAR Polarimetry and Polarimetric Interferometry
    Presentation's date: 2011-01-24
    Presentation of work at congresses

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  • Programa de la "WEEK OF SCIENCE" Madrid 12-16 Sept. 2011

     Redondo Apraiz, Jose Manuel; Ferriz, Antonio; Morozov, Evgeny
    Symposium on Geophysical and Astrophysical Flows and Related Problems
    Presentation's date: 2011-09-16
    Presentation of work at congresses

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  • Mixing and vorticity structure in stratified oceans

     Matulka, Anna Magdalena; Redondo Apraiz, Jose Manuel
    Geophysical research abstracts
    Date of publication: 2010-06-06
    Journal article

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  • Intermittency in non-homogeneous wake and jet turbulence

     Ben Mahjoub Akalay, Otman; Sekula, Emil; Redondo Apraiz, Jose Manuel
    Geophysical research abstracts
    Date of publication: 2010-05-05
    Journal article

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  • Multifractality in the atmospheric boundary layer

     Vindel, Jose M.; Yague, Carlos; Redondo Apraiz, Jose Manuel
    Geophysical research abstracts
    Date of publication: 2010-05-05
    Journal article

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  • The structure of rotating stratified flows

     Redondo Apraiz, Jose Manuel
    International Workshop on the Physics of Compressible Turbulence Mixing
    Presentation's date: 2010-07-16
    Presentation of work at congresses

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  • Vortex decay in stratified flows

     Redondo Apraiz, Jose Manuel; Matulka, Anna Magdalena; Carrillo Cortes, Jose Alejandro
    Topical Problems of Fluid Mechanics
    Presentation's date: 2010-02-11
    Presentation of work at congresses

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  • Oil spill detection and prediction in the NW Mediterranean Sea: new multifractal methods for SAR analysis

     Redondo Apraiz, Jose Manuel; Platonov, Alexei
    European Conference on Computational Fluid Dynamics
    Presentation's date: 2010-06-17
    Presentation of work at congresses

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    The oil pollution of Gulf of Lion in the NW Mediterranean has been studied with SAR images during the period 1999 -2005. We have analyzed these SAR images with respect to other surface features such as wind, river plumes, eddies and convergence areas. Some results of our statistical analysis are presented showing that the NW Mediterranean is most polluted along the main ship traffic routes, but comparatively less that near other routes in the Indic and the Pacific. The oils spill index is higher than one. The sizes of the detected oil spills vary over a large range, and if the statistics of the largest accidents are also considered on a longer timescale, we show that Zipf's Law, relating the frequency and the size of the spill in a hyperbolic fashion is applicable. Advanced image analysis techniques, such as the calculation of the multi-fractal dimensions of the observed SAR signatures, have been applied to distinguish between natural slicks and antropogenic spills. Fractal dimensions can also be used to predict the time of release of the spill, non-dimensionalised with local turbulent dissipation. The multi-scale appearance and the topological structure of the slicks and spills may also be used as a useful measure of the diffusivity, yielding additional information which in turn may improve automated detection algorithms and be used in numerical models.

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    Multiscale analysis of SAR from the earth surface  Open access

     Redondo Apraiz, Jose Manuel; Tarquis Alfonso, Ana Maria; Matulka, Anna Magdalena; Platonov, Alexei
    Workshop on Advances in Turbulence
    Presentation's date: 2010-08
    Presentation of work at congresses

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    The use of Synthetic Aperture Radar (SAR) to investigate the earth’s surface provides a wealth of useful information. Here we will discuss some recent fractal and multi-fractal techniques used to identify oil spills and the dynamic state of the Ocean as well as the mountain structures in the solid earth. It is important both in the Ocean and in the Atmosphere to be able to parametrize mixing at the Rossby Deformation Radius scale (i.e. most energetic eddy scale) to aid in the prediction of pollutant dispersion. Results presented here aim to identify different SAR signatures and at the same time provide calibrations for the different local configurations that allow to predict the behaviour of different tracers in the sea surface, in the atmosphere or in the earth. We also compare different SAR images of the Eastern Pyrenees, evaluating the changes in structure as a function of average height. The multiple correlations between HH HV VV polarizations and the images are used to calculate the fractal dimension with the Box-Counting method. The distribution of the boxes is accomplished systematically for each SAR intensity level, ρ the intersection of these boxes with the images gives N(ρ) boxes with a non void intersection, which may be compared with the standard multifractal formalism.

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    Evolution of the Thorpe and Ozmidov scales at the lower atmospheric and planetary boundary layer  Open access

     Lopez Gonzalez-Nieto, Pilar; Cano Marchante, Jose Leandro; Redondo Apraiz, Jose Manuel
    Workshop on Advances in Turbulence
    Presentation's date: 2010-08-05
    Presentation of work at congresses

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    Turbulence affects the dynamics of atmospheric processes by enhancing the transport of mass, heat, humidity and pollutants. The global objective of our work is to analyze some turbulent descriptors which reflect the mixing processes in the atmospheric boundary layer (ABL). In this paper we present results related to the Thorpe displacements dT, the maximum Thorpe displacement (dT)max, the Thorpe scale LT and the Ozmidov scale, LO, and their time evolution in the ABL during a day cycle. A tethered balloon was used to obtain vertical profiles of the atmospheric physical magnitudes up to 1000 m. We discuss their vertical and time variability, and also their relationships.

    Postprint (author’s final draft)

  • Flow percolation in non homogeneous Hele-Shaw flows

     Lopez Gonzalez-Nieto, Pilar; Redondo Apraiz, Jose Manuel; Hernández, David; Tarquis Alfonso, Ana Maria
    European Geosciences Union General Assembly
    Presentation's date: 2010-05-06
    Presentation of work at congresses

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  • Mixing in Richtmyer Meshkov and Rayleigh Taylor fronts

     Redondo Apraiz, Jose Manuel; Vila, Teresa; Garzon, G.; Rozanov, V.B.; Gushkov, S.
    European Geosciences Union General Assembly
    Presentation's date: 2010-05-05
    Presentation of work at congresses

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  • Hierarchy compensation of non-homogeneous intermittent atmospheric turbulence

     Redondo Apraiz, Jose Manuel; Ben Mahjoub Akalay, Otman; Rodriguez Cantalapiedra, Inmaculada
    European Geosciences Union General Assembly
    Presentation's date: 2010-05-04
    Presentation of work at congresses

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  • Multifractal analysis of SAR of the ocean surface, currents, eddy structure, oil slicks and diffusivity analysis

     Redondo Apraiz, Jose Manuel; Grau, J.; Matulka, Anna Magdalena; Platonov, Alexei
    European Conference on Computational Fluid Dynamics
    Presentation's date: 2010-06-17
    Presentation of work at congresses

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    Flow structure and resistance in flexible vegetated channels  Open access

     Velasco Montes, David; Bateman Pinzon, Allen; Redondo Apraiz, Jose Manuel
    Workshop on Advances in Turbulence
    Presentation's date: 2010-08-05
    Presentation of work at congresses

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    The present paper helps to understand the behaviour of the flow through plants, as a first approximation to the environmental interactions happening in natural rivers.

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  • Environmental geosciences lectures and transversal public workshops

     Redondo Apraiz, Jose Manuel; Redondo, A.; Babiano, Armando
    European Geosciences Union General Assembly
    Presentation's date: 2010-05-04
    Presentation of work at congresses

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  • Irregularity of wetting fronts in heterogeneous porous media

     Tarquis Alfonso, Ana Maria; Redondo Apraiz, Jose Manuel; Ryansantsev, Yury; Lopez Gonzalez-Nieto, Pilar
    Workshop on Advances in Turbulence
    Presentation's date: 2010-08
    Presentation of work at congresses

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  • Multifractality in the atmospheric boundary layer

     Vindel, Jose M.; Yagüe, C.; Redondo Apraiz, Jose Manuel
    Workshop on Advances in Turbulence
    Presentation's date: 2010-08-02
    Presentation of work at congresses

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  • Richmyer-Meshkov and Rayleigh-Taylor turbulent mixing fronts and instabilities

     Redondo Apraiz, Jose Manuel; GARZON BEDOYA, GERMAN; Rozanov, V.B.; Gushkov, S.
    Workshop on Advances in Turbulence
    Presentation's date: 2010-08
    Presentation of work at congresses

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    ROFI structure in the gulf of Lions and the NW Mediterranean Sea: field and remote sensing observations of surface coherent structures  Open access

     Fraunie, Philippe; Redondo Apraiz, Jose Manuel; Platonov, Alexei; Diez Rilova, Margarita; Matulka, Anna Magdalena
    Workshop on Advances in Turbulence
    Presentation's date: 2010-08-04
    Presentation of work at congresses

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    The advances in radar sensors may be applied to study the flow in the region of fresh water influence (ROFI) region of the ocean. The Synthetic Aperture Radar (SAR) is a useful tool that may be used to study both marine water dynamics and its pollution. Oil spills and natural slicks may be detected and processed with advanced computer techniques to reveal vortex dynamics and turbulence spectral characteristics of the complex eddy and current interaction in the ocean surface. In the framework of the European Union contract Clean Seas, more than 300 SAR images of the North-west Mediterranean Sea area taken between December 1996 and December 1998 were analyzed. 255 eddies can be detected under certain conditions and we analyzed statistically the appearance, size and position of vortices in the test area. It is shown that the maximum size of the eddies detected near the coast is limited by the Rossby deformation radius To be discussed and that there is a decrease in size in the coastal waters in the direction of the Liguro-Provenzal current with the largest eddies occurring near the cape of Rosas. The role of submarine canyons in the vortex generation is indicated by the asymmetry of their distribution with respect to the thalwegs. It is demonstrated that useful information of a geometrical nature obtained by SAR satellite images may be used to estimate relevant dynamical parameters of coastal flows

    Postprint (author’s final draft)

  • Numerical LES models of Richtmyer-Meshkov and Rayleigh-Taylor instabilities

     GARZON BEDOYA, GERMAN; Redondo Apraiz, Jose Manuel; Rozanov, V.B.; Gushkov, S.
    Workshop on Advances in Turbulence
    Presentation's date: 2010-08-03
    Presentation of work at congresses

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  • Scaling and isotropy in the inertial range of atmospheric turbulence

     Marino, Rafaelle; Sorriso, Luca; Redondo Apraiz, Jose Manuel; Yague, Carlos
    European Geosciences Union General Assembly
    Presentation's date: 2010-05-05
    Presentation of work at congresses

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  • Direct numerical simulation of internal waves formation in highly stratified wake flow

     Houcine, H.; Chaschechkin, Yuli; Fraunie, Philippe; Redondo Apraiz, Jose Manuel; Gharbi, Abdel
    European Conference on Computational Fluid Dynamics
    Presentation's date: 2010-06-16
    Presentation of work at congresses

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  • Gravity and turbidity currents

     Bolster, Diogo; Bateman Pinzon, Allen; Redondo Apraiz, Jose Manuel; Bezerra Menezes, Maria Ozilea
    European Geosciences Union General Assembly
    Presentation's date: 2010-05-02
    Presentation of work at congresses

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  • Summer Course and workshop on Environmental Turbulence (2-7 August 2010)

     Lopez Gonzalez-Nieto, Pilar; Tarquis Alfonso, Ana Maria; Redondo Apraiz, Jose Manuel
    Date: 2010-08-02
    Report

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  • Diffusion and scaling in the ocean surface

     Diez, Margarita; Bezerra, Maria Ozilea; Vila, Teresa; Castilla Lopez, Roberto; Redondo Apraiz, Jose Manuel
    Topical Problems of Fluid Mechanics
    Presentation's date: 2010-02-10
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  • Turbulent structure in environmental flows: effects of stratification and rotation  Open access

     Matulka, Anna Magdalena
    Defense's date: 2010-03-19
    Department of Engineering Design, Universitat Politècnica de Catalunya
    Theses

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    Several series of experiments in stratified and in rotating/stratified decaying flows after a grid is used to stir the two layer stable fluid brine and fresh water set up. We measure by comparing the gained potential energy with the available kinetic energy AKE, the relative efficiency of mixing. The experiments in stratified rotating flows with grid driven turbulence were both periodic (quasi stationary) and non-monotonic (decaying) forcing. This thesis compares experimental, numerical and field observations on the structure and Topology of the Stratified Rotating Flows as well as their decay, the horizontal spectra changes appreciable with slopes from 1.1 to 5, but vorticity and local circulation, and also the initial topology and forcing of the flow. A detailed study of the vorticity decay and vortex and energy structure has been performed, the new results show that neither stratified nor rotating flows exhibit pure 2D structures. The work parameterizes the role of the Richardson number and the Rossby number, both in the experiments and in the ocean visualizations is very important. The conditions of vortex decay show the effects of the internal waves in the decay turbulent conditions both for stratified and rotating flows. The parameter space (Re,Ri,Ro) has been used to interpret many previously disconnected explanations of the 2D-3D turbulent behaviour. The comparison of numerical simulations with experiments has allowed implementing new theoretical aspects of the interaction between waves and vortices finding the surprising and very interesting result that these interactions depend on the level of enstrophy. This also leads to new ways of using multifractal analysis ad intermittency in ocean environmental observations. A large collection of SAR images obtained from three European coastal areas were used for routine satellite analysis by SAR and other sensors, which seem very important to build seasonal databases of the dynamic conditions of ocean mixing. The topology of the basic flow is very important and in particular the topology of the vortices and their decay which depends on ambient factors such as wave activity, wind and currents. We find more realistic estimates of the spatial/temporal non-homogeneities (and intermittency obtained as spatial correlations of the turbulent dissipation); these values are used to parameterize the sea surface turbulence, as well as a laboratory experiments at a variety of scales. Using multi-fractal geometry as well, we can establish now a theoretical pattern for the turbulence behaviour that is reflected in the different descriptors. Vorticity evolution is smoother and different than that of scalar or tracer density. The correlation between the local Ri and the fractal dimension detected from energy or entropy is good. Using multi-fractal geometry we can also establish certain regions of higher local activity used to establish the geometry of the turbulence mixing that needs to be studied in detail when interpreting the complex balance between the direct 3D Kolmogorov type cascade and the Inverse 2D Kraichnan type cascade.

  • Relationship between intermittency and stratification

     Vindel, Jose M.; Yague, Carlos; Redondo Apraiz, Jose Manuel
    Nuovo cimento della Società Italiana di Fisica C. Geophysics and space physics
    Date of publication: 2009-04-09
    Journal article

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    A formal analogy exists between 2D turbulence and 3D turbulence with stratification and rotation. Although the effect of the rotation, to the scale typical of the turbulence, is negligible in the atmosphere, we have found a relationship between the behavior of the intermittency and that of the atmospheric stratification. In order to do that, the intermittency has been characterized through the flatness of the PDFs of velocity increments, for the smallest possible scale, present in our measurements.

  • Filtered deterministic waves and analysis of the fractal dimension of the components of the wind velocity

     Tijera, Manuel; Cano Marchante, Jose Leandro; Cano, D.; Bolster, Diogo; Redondo Apraiz, Jose Manuel
    Nuovo cimento della Società Italiana di Fisica C. Geophysics and space physics
    Date of publication: 2009-03-29
    Journal article

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    The difficulty in developing models for waves in turbulent flows is a key problem in the analysis of the complexity of turbulence. We present a method to find and filter perturbations that are generated by the flow of deterministic waves from the power spectrum in the atmospheric boundary layer (ABL). The perturbation model proposed assumes that the amplitude and frequency of such waves decay with time exponentially. For illustrative purposes, we apply the technique to three time series of wind velocities obtained with a sonic anemometer. This analytical procedure allows us to filter waves of the proposed structure with a 99% significance level in the power spectrum. We have applied the same method to 540 such wind series, all painting similar results. We then compare the fractal dimension of the original series to those from which the waves have been removed. We find that the fractal dimension of the filtered waves is slightly less than that of the original series. Finally, we consider the fractal dimension of the studied series as a function of the length-scales and dissipation rate of kinetic energy per unit mass. Our results suggest an increase of fractal dimension with both length-scale and dissipation rate of kinetic energy.

  • Application of aerial video images for Lagrangian tracer studies in maritime and estuarine port zones

     Bezerra, MO; Akel, AR; Araujo, TRC; Krelling, APM; Redondo Apraiz, Jose Manuel
    Journal of coastal research
    Date of publication: 2009-01
    Journal article

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  • Fractal aggregates evolution of methyl red in liquid crystal

     Ciuchi, F; Sorriso-Valvo, L; Mazzulla, A; Redondo Apraiz, Jose Manuel
    European physical journal E
    Date of publication: 2009-06
    Journal article

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  • Induced structures under seasonal flow conditions in the Ebro delta shelf: Laboratory and numerical models

     Carrillo Cortes, Jose Alejandro; Redondo Apraiz, Jose Manuel; Fraunie, Philippe; Durand, Nathalie
    Nuovo cimento della Società Italiana di Fisica B. General physics relativity
    Date of publication: 2009-07-28
    Journal article

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    The characteristic induced length scale produced by a river flow in its outlet is studied. Two experimental methods are compared: a) Physical modeling in laboratory and b) numerical mesoscale diffusion model; under low tidal and realistic seasonal flow conditions from Spring, Summer, Fall and Winter field data from the Ebro delta shelf. The physical laboratory experiences were performed on a five-meter diameter turntable, using the Froude-Rossby similarity. This paper shows complementary results from both methods investigating the vortex characteristic and the dynamics of the flow. The experimental results under rotating conditions show coherent vortex dynamics in the large-meso scale coastal boundary. The numerical model, on the other hand, lacks the mesoscale vortex dynamics and its induced diffusion but gives reasonable flow conditions in the close region (15–20 km) around the river mouth. Both the experiments and numerical simulations show river plume diffusion smaller than D2 α t3.

  • Experimental measurements and diffusion in harbor and coastal zones

     Diez Rilova, Margarita; Bezerra Menezes, Maria Ozilea; Mösso Aranda, Octavio Cesar; Castilla Lopez, Roberto; Redondo Apraiz, Jose Manuel
    Nuovo cimento della Società Italiana di Fisica C. Geophysics and space physics
    Date of publication: 2009-07-17
    Journal article

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    Experimental results of turbulent flows in the sea surface near the coastline have been performed using both Lagrangian and Eulerian methods, field tests are presented using video recordings and velocity sensors. The spatial and temporal resolution is limited by the measuring instruments, which results in “filtering” out the very small scales. The experimental field-results obtained during the large-scale surf zone experiments carried out in the Ebro Delta, (Spain), under spilling/plunging breaking waves are compared with experiments performed at the Barcelona harbour. The field-measurements include several tests across the surf zone with high vertical resolution. The measured turbulent properties are compared with macroturbulence characteristics and length parameterisations. Diffusion is measured and related to the local velocity spectra so that a generalized Richardson law may be used.