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  • Hydrodynamics in a multivortex aquaculture tank: Effect of bafflesand water inlet characteristics

     Masalo Llora, Ingrid; Oca Baradad, Joan
    Aquacultural engineering
    Date of publication: 2014
    Journal article

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    The superior hydrodynamics of circular tanks over rectangular tanks are well known by aquaculturists; yet rectangular tanks are still widely used because of their easier handling. As a consequence, several studies have focused on the hydrodynamics of rectangular tanks, where rotating flow cells are generated by injecting water tangentially to the tank wall with the outlet placed in the center of the cell. In the present work, we evaluate the hydrodynamics in a rectangular tank with 4 rotating flow cells of 1m diameter, which is called multivortex tank. We also analyze baffle placement between two consecutive water inlets and the characteristics of the water inlet (flow rate and inlet velocity), which then allows us to determine the average velocities and the distribution uniformity of these velocities. The obtained results are compared with a circular tank having the same cell diameter and inlet configurations as the multivortex tank. Baffle placement between two consecutive water inlets in the multivortex tank helps increase the average velocity, the uniformity of velocities and the symmetry in the rotating flow cells. In configurations without baffles, the combination of low flow rate and high impulse force present the lowest symmetry. Differences between intermediate and extreme cells were observed. In all configurations tested, velocities and uniformities were higher in extreme cells than in intermediate cells. In the circular tank the average velocities achieved were higher than in the multivortex tank with the same impulse force, but the uniformity of velocities were higher in the multivortex tank. Finally, the proportionality between the average velocity and the square root of the impulse force for a specific tank geometry has been corroborated in commercial scale models.

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    Flow pattern in aquaculture circular tanks: Influence of flow rate, water depth, and water inlet & outlet features  Open access

     Oca Baradad, Joan; Masalo Llora, Ingrid
    Aquacultural engineering
    Date of publication: 2013-01
    Journal article

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  • Influence of substrate on growth and health of young sole (Solea senegalensis)

     Almansa, Clara; Oca Baradad, Joan; Reig Puig, Lourdes
    Aquaculture Conference
    Presentation's date: 2013-11-05
    Presentation of work at congresses

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  • Reliability of laser scanner to estimate sole (Solea senegalensis) biomass under intensive conditions

     Almansa, Clara; Reig Puig, Lourdes; Oca Baradad, Joan
    Aquaculture Conference
    Presentation's date: 2013-11-06
    Presentation of work at congresses

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  • Non aerated seaweed culture tank with rotating flow

     Flo, V.; Oca Baradad, Joan
    Aquaculture Conference
    Presentation's date: 2013-11-05
    Presentation of work at congresses

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  • Distribution of sole (Solea senegalensis) in a raceway tank with different environmental conditions

     Almansa, Clara; Reig Puig, Lourdes; Oca Baradad, Joan
    Aquaculture Conference
    Presentation's date: 2013-11-06
    Presentation of work at congresses

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    Effect of start-up conditions on nitrification rates: Ammonia concentrations and salinity  Open access

     Masalo Llora, Ingrid; Oca Baradad, Joan
    International conference on Recirculating Aquaculture
    Presentation's date: 2012-08-25
    Presentation of work at congresses

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    Rotating flow cell formation in a multivortex tank  Open access

     Masalo Llora, Ingrid; Oca Baradad, Joan
    Global Aquaculture, Securing our future
    Presentation's date: 2012-09-04
    Presentation of work at congresses

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  • Starting-up nitrifying biofilters under different environmental conditions

     Carroza, Carlos; Masalo Llora, Ingrid; Oca Baradad, Joan
    Global Aquaculture, Securing our future
    Presentation's date: 2012-09-03
    Presentation of work at congresses

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  • Effect of the presence of sole (Solea senegalensis) on the vertical gradient of oxygen as a function of water velocity

     Reig Puig, Lourdes; Almansa, Clara; Carretero, Francesc; Oca Baradad, Joan
    AQUA 2012 - Conference
    Presentation of work at congresses

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  • Analysis of night-time climate in plastic-covered grenhouses  Open access

     Piscia, Davide
    Defense's date: 2012-12-18
    Department of Heat Engines, Universitat Politècnica de Catalunya
    Theses

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    Este trabajo analiza el clima nocturno del invernadero. EL objeto del estudio es el invernadero de plástico sin calefacción, cuyo clima se estudia utilizando modelos CFD, modelos basados en los balance de energía (ES) y s datos experimentales. El fin es doble, por un lado se trata de analizar y comprender el clima nocturno del invernadero, y proponer soluciones a los problemas relacionados con las altas tasas de humedad. Por otro lado se investigan nuevos métodos de simulación del clima del invernadero, métodos basados en el uso conjunto o acoplamiento de modelos CFD y ES , y también basados en la técnica de optimización. El Capitulo 1 introduce el contexto general y los objetivos que plantea el trabajo. El Capitulo 2 estudia el clima nocturno en un invernadero de capa sencilla. Para ello desarrolla un modelo CFD que incluye una UDF (User Define Function) para calcular la tasa de condensación. Una vez validado el modelo se analiza el comportamiento del invernadero bajo distintas condiciones de contorno.. El Capitulo 3 analiza una solución para combatir las bajas temperaturas nocturnas, la pantalla térmica. Los efectos de la pantalla se analizan mediante el uso del CFD. Se lleva a cabo una comparación completa entre el invernadero de capa sencilla y el invernadero con pantalla. El capitulo proporciona información detallada sobre el clima del invernadero y presenta un estudio paramétrico del efecto de la temperatura equivalente del cielo y la cesión de calor desde el suelo en el clima del invernadero con pantalla térmica. EL Capitulo 4 presenta un nuevo método para optimizar el diseño del invernadero. El método se basa en el acoplamiento de dos algoritmos de optimización que operan con el modelo ES. A su vez el modelo ES está conectado con el modelo CFD. El objetivo es doble, por un lado introducir una nueva manera de optimizar el diseño del invernadero, y por el otro lado tratar de resolver uno de los problemas evidenciados en el capítulo 2. El resultado muestra que un material de cubierta de alto poder de reflexión del infrarrojo lejano aportaría mejorías relevantes al clima del invernadero. El Capitulo 5 presenta un modelo acoplado para el estudio del clima del invernadero. EL CFD se utiliza para proporcionar las tasas de ventilación y los coeficientes convectivos al modelo ES. Esta técnica se utiliza para estudiar los efectos de diferentes estrategias de ventilación sobre el régimen de humedad con diferentes condiciones externas. Finalmente, el Capitulo 6 resume las conclusiones y propone algunos temas para futuras investigaciones

    This work studied night-time greenhouse climate. The focus was on unheated plastic greenhouses and analyses were carried out using CFD models, Energy balance (ES) models and experimental data. The aims were twofold: on the one hand, it was intended to analyse and understand night-time greenhouse climate and propose solutions to the high-humidity issue. On the other hand, the aim was to investigate novel simulation approaches based on the coupling of CFD and ES models as well as the use of optimisation algorithms to study greenhouse climate. Chapter 1 is an introductory chapter which includes the general context and overall research objectives. Chapter 2 studies night-time climate in single-layer greenhouses by means of CFD. The model is validated and condensation User Defined Function (UDF) is introduced which accounted for the condensation rate found on the inner face of the greenhouse cover. Chapter 3 studies a commonly used solution to the issue of low night-time temperature. A thermal screen was analysed by means of CFD simulations. A thorough comparison was made between single-layer and screened greenhouses and detailed information was provided in order to build a framework for taking decisions as to whether to use a screen or not. Chapter 4 introduces a novel approach to optimizing greenhouse design; the approach relies on two optimization algorithms linked to an ES model which was coupled to a CFD model. The aim of the study was twofold: on the one hand to introduce a method offering a general approach for optimizing greenhouse design and on the other, to attempt to solve one of the issues highlighted in Chapter 2. It was shown that using a highly reflective covering material would have a theoretically significant impact on greenhouse performance. Chapter 5 introduces a coupled model for studying greenhouse climate. The CFD was used to provide the ventilation rate and convective coefficients for the ES model. This approach was applied to study the effects of different ventilation strategies on humidity under different outside air conditions. Finally Chapter 6 summarizes the conclusions and proposes themes for future research.

  • Use of laser scanning to evaluate turbot (Scophthalmus maximus) distribution in raceways with different water velocities

     Almansa Lagunas, Clara; Reig Puig, Lourdes; Oca Baradad, Joan
    Aquacultural engineering
    Date of publication: 2012-11
    Journal article

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    Evaluación hidrodinámica de un tanque acuícola tipo multivórtice  Open access

     Masalo Llora, Ingrid; Oca Baradad, Joan
    Congreso Nacional de Acuicultura
    Presentation's date: 2011-11-23
    Presentation of work at congresses

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  • Efecto de la presencia de lenguados (Solea senegalensis) sobre el gradiente vertical de oxígeno en función de la velocidad de agua

     Almansa Lagunas, Clara; Oca Baradad, Joan; Carretero, Francesc; Reig Puig, Lourdes
    XIII Congreso Nacional de Acuicultura
    Presentation's date: 2011-11-22
    Presentation of work at congresses

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  • Influencia de la estrategia de alimentación en la distribución del lenguado (Solea senegalensis)

     Almansa, Clara; Reig Puig, Lourdes; Oca Baradad, Joan
    XIII Congreso Nacional de Acuicultura
    Presentation of work at congresses

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  • Influence of tank geometry and flow pattern in fish distribution

     Duarte Ortega, Sonia; Reig Puig, Lourdes; Masalo Llora, Ingrid; Blanco Abellan, Monica; Oca Baradad, Joan
    Aquacultural engineering
    Date of publication: 2011
    Journal article

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  • XIII Congreso Nacional de Acuicultura

     Oca Baradad, Joan; Masalo Llora, Ingrid; Reig Puig, Lourdes
    Participation in a competitive project

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  • XIII Congreso Nacional de Acuicultura

     Oca Baradad, Joan; Masalo Llora, Ingrid; Reig Puig, Lourdes
    Participation in a competitive project

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  • J-09412

     Masalo Llora, Ingrid; Oca Baradad, Joan; Reig Puig, Lourdes
    Participation in a competitive project

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  • XIII Congreso Nacional de Acuicultura

     Oca Baradad, Joan; Masalo Llora, Ingrid; Reig Puig, Lourdes
    Participation in a competitive project

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  • Diseño de tanques en acuicultura intensiva

     Oca Baradad, Joan; Masalo Llora, Ingrid; Gutiérrez, Carmen
    ipac Acuicultura
    Date of publication: 2011-11-15
    Journal article

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  • Distribution of velocities in aquaculture circular tanks with rotating flow and evaluation of uniformity

     Masalo Llora, Ingrid; Oca Baradad, Joan
    Aquaculture Europe 2010. Seafarming tomorrow
    Presentation's date: 2010-10
    Presentation of work at congresses

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  • Preference of cultured sole (Solea senegalensis) for different substrates differing in material, texture and colour

     Reig Puig, Lourdes; Duarte Ortega, Sonia; Valero Baya, Jordi; Oca Baradad, Joan
    Aquacultural engineering
    Date of publication: 2010
    Journal article

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  • Clogging in Horizontal Subsurface Flow Constructed Wetlands. Mesures, design factors and prevention strategies  Open access  awarded activity

     Pedescoll Albacar, Anna
    Defense's date: 2010-11-04
    Department of Agri-Food Engineering and Biotechnology, Universitat Politècnica de Catalunya
    Theses

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    Constructed wetlands are alternative systems to conventional wastewater treatment for small communities (up to 2000 PE). This is mainly due to that operation and maintenance costs are reduced. Despite the advantages, the clogging of the bed is the most important trouble encountered by the managers of subsurface flow wetlands treatment systems. The solids accumulation in the interstitial spaces of the gravel over time causes the decrease of both, hydraulic conductivity and porosity. This leads in the development of preferential paths and short-circuiting of the water through the wetland, which converge in overland flow and contaminant removal efficiency decrease. Therefore, clogging is the main limiting factor of the life span of a subsurface flow constructed wetland. The strategies to reverse clogging imply important economic investments. Generally, the most widespread option is the replacement of gravel. Hence the need to measure realibly the degree of clogging of a system in order to identify the factors that influence this phenomenon and to search new configurations and strategies to delay its progress, thus operations needed to reverse it. Therefore, the aims of this thesis must contribute to establish new design criteria and operation of horizontal subsurface flow constructed wetlands to minimize clogging processes without reducing the contaminant removal efficiency. Then, the objectives were to compare a method to measure hydraulic conductivity in situ, based on falling head permeameter, in order to determine the state of clogging of wetlands and its horizontal distribution; to determine the most suitable indicator to assess clogging in horizontal subsurface flow wetlands; to identifie new design and operation parameters likely to cause or encourage the clogging of the filter medium; and to analyse two new configurations in a pilot scale system in terms of contaminant removal and clogging development. Among the different clogging indicators analysed (drenable porosity, hydraulic conductivity, accumulated solids and effective volume from a tracer test), hydraulic conductivity seems to be the best one. Firstly, because hydraulic conductivity provides information about the hydraulic behaviour inside the bed, and linked appropriately with the accumulated solids (a correlation of 74.5% was found between both indicators). Secondly, because its application in full-scale wetlands is more straightforward than other techniques.

    Los humedales construidos son una alternativa al tratamiento convencional de agua residual para pequeños municipios (hasta 2000 hab-eq) ya que son fáciles de operar y mantener y tienen un coste de explotación bajo. El mayor inconveniente a que se enfrentan los explotadores de sistemas de tratamiento con humedales subsuperficiales es la colmatación del lecho. Con el tiempo, la acumulación de sólidos de diversa naturaleza en los espacios intersticiales del medio filtrante, provoca la disminución de la conductividad hidráulica y la porosidad iniciales de la grava. Esto conduce al desarrollo de caminos preferenciales y cortocircuitos en el curso del agua que convergen en la aparición de agua en superficie. A la larga, esto puede comprometer la capacidad depurativa del sistema. Por ello, la colmatación supone el factor limitante de la vida útil de un humedal construido. Las estrategias para solventar la colmatación, una vez se ha producido, son costosas y pasan por realizar inversiones no despreciables. Generalmente la opción más extendida es el cambio del material granular. De ahí la necesidad de medir, de manera fiable, en qué grado un sistema está colmatado, identificar los factores que influyen en el fenómeno e indagar en nuevas configuraciones y estrategias que permitan retrasar el avance de la colmatación y consigo, aplazar las intervenciones necesarias para devolver al sistema un estado óptimo de funcionamiento. Los objetivos de esta tesis doctoral han de contribuir a establecer nuevos criterios de diseño y operación de humedales construidos de flujo subsuperficial horizontal para minimizar, o cuanto menos retrasar, la colmatación de estos sistemas, sin mermar la eficiencia de eliminación de contaminantes del agua residual. Por ello, los objetivos son cuantificar la precisión y exactitud de un método de medición in situ de la conductividad hidráulica, basado en el permeámetro de carga variable, para la determinación del grado de colmatación de un lecho y la distribución horizontal de la misma; estudiar la idoneidad de diferentes indicadores de la colmatación de un humedal de flujo subsuperficial horizontal; evaluar la incidencia de diferentes factores de diseño y operación de humedales de flujo subsuperficial horizontal en el proceso de la colmatación; y caracterizar (en términos de eficiencia de eliminación de contaminantes y de evolución de la colmatación) dos nuevas configuraciones de humedales construidos a escala piloto.

    Els aiguamolls construïts són una alternativa al tractament convencional d’aigua residual per a petits municipis (fins 2000 hab-eq) degut, principalment, a la facilitat en llur operació i manteniment y a les reduïdes despeses d’explotació. L’inconvenient més important amb què es troben els explotadors de sistemes de tractament amb aiguamolls subsuperficials és la colmatació del llit. Al llarg del temps, l’acumulació de sòlids de diversa natura en els espais intersticials de la grava, provoca la disminució de la conductivitat hidràulica i la porositat inicials. Això condueix al desenvolupament de camins preferencials i curtcircuits en el curs de l’aigua a través de l’aiguamoll, que convergeixen en l’aparició d’aigua en superfície, i que, a llarg termini pot comprometre la capacitat depurativa del sistema. Per això, la colmatació suposa el factor limitant de la vida útil d’un aiguamoll construït. Les estratègies per a fer front a la colmatació, un cop s’ha produït, passen per realitzar inversions econòmiques gens menyspreables. Generalment, l’opció més extesa és la reposició del material granular. D’aquí neix la necessitat de mesurar, de manera fiable, el grau de colmatació d’un sistema, d’identificar aquells factors que influeixen en el fenomen y qüestionar noves configuracions y estratègies que permetin retardar l’avenç de la colmatació, i per tant ajornar les intervencions necessàries per tornar al sistema a l’estat òptim de funcionament. Per tot això els objectius d’aquesta tesi doctoral han de contribuir a establir nous criteris de disseny i operació d’aiguamolls construïts de flux subsuperficial horitzontal per tal de minimitzar la colmatació d’aquests sistemes, sense minvar l’eficiència d’eliminació de contaminants de l’aigua residual. Els objectius específics són quantificar la precisió i exactitud d’un mètode de mesura in situ de la conductivitat hidràulica, basat en el permeàmetre de càrrega variable, per a la determinació de l’estat de colmatació d’un llit així com la distribució horitzontal d’aquesta; determinar l’indicador més adecuat per avaluar la colmatació d’un aiguamoll construït de flux subsuperficial horitzontal; identificar nous paràmetres de disseny y operación susceptibles de causar o afavorir la colmatación del medi filtrant; i caracteritzar (en termes d’eliminació de contaminants i d’evolució de la colmatación) dues noves configuracions d’aiguamolls construïts a escala pilot.

  • Aplicación de las técnicas de análisis digital de imágenes para el estudio del comportamiento de peces de cultivo

     Duarte Ortega, Sonia
    Defense's date: 2010-11-05
    Department of Agri-Food Engineering and Biotechnology, Universitat Politècnica de Catalunya
    Theses

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  • DESARROLLO DE LA TECNOLOGIA ACUICOLA EN TIERRA PARA LA PRODUCCION MARINA INTENSIVA EN EL MEDITERRANEO

     Reig Puig, Lourdes; Masalo Llora, Ingrid; Duarte Ortega, Sonia; Sanchez Fernandez, Pablo; Almansa Lagunas, Clara; Oca Baradad, Joan
    Participation in a competitive project

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  • 2010 Aquacultural Engineering Society Awards

     Masalo Llora, Ingrid; Guadayol, Oscar; Peters, Francesc; Oca Baradad, Joan
    Award or recognition

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  • Measurement of sole activity by digital image analysis

     Duarte Ortega, Sonia; Reig Puig, Lourdes; Oca Baradad, Joan
    Aquacultural engineering
    Date of publication: 2009-07
    Journal article

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    Evaluating flatfish activity can be a useful tool for studying fish behavior and welfare. The aim of this workwas to obtain a quantitative index for measuring flatfish activity using image analysis. Accordingly, motor activity of a sole population was recorded by digital video for three nights, bearing in mind the nocturnal lifestyle of the species. Subsequent image analysis was done by image subtraction of consecutive frames. The result was a ‘‘difference frame’’ showing the changes in the image area due to fish movement. Using these data, an image processing activity index (IPAI) was determined by measuring the percentage of area altered due to fish movement and by taking this percentage as an indicator of fish activity. Typical sole behavioral acts (take-off and surface swimming) were recorded by direct observation during the same intervals in order to calibrate the IPAI. A direct observation activity index (DOAI) was determined by weighting each kind of attitude according to its average duration. Results obtained from image analysis (IPAI) were compared with results obtained by direct observation (DOAI). A linear relationship between the two indexes was found with a correlation coefficient of r2 = 0.80 for 92% of coverage area tank and r2 = 0.90 for 210% of coverage area tank. Thus, this digital video-based index can be a highly reliable and accuratemethod for objectivelymeasuring activity levels in sole with a low consumption of labor and time. Nevertheless, the application to farm conditions would need further research and an accurate calibration for other species.

  • Metodologías para la definición de criterios de diseño de tanques para el cultivo de peces planos

     Oca Baradad, Joan; Masalo Llora, Ingrid; Duarte Ortega, Sonia; Almansa Lagunas, Clara; Reig Puig, Lourdes
    XII Congreso Nacional de Acuicultura
    Presentation's date: 2009-10-26
    Presentation of work at congresses

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  • Analysis of sedimentation and resuspension processes of aquaculture biosolids using an oscillating grid  awarded activity

     Masalo Llora, Ingrid; Guadayol, Oscar; Peters, Francesc; Oca Baradad, Joan
    Aquacultural engineering
    Date of publication: 2008-01
    Journal article

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    Sedimentation and resuspension processes of aquaculture biosolids (non-ingested feed and faeces) are analysed using vertically oscillating grids as a source of turbulence in fluid tanks. An oscillating grid system consists of a container in which a grid is stirred vertically generating a well-known turbulent field that is function of amplitude and frequency of oscillation, distance between grid and measurement point, and mesh spacing of the grid. The grid used in this study had a mesh spacing of 1.2 cm, and was calibrated using different amplitudes (1, 1.5 and 2 cm), frequencies (from 1 to 6 Hz) and distances (2.4, 2.7 and 3 cm). After calibration, the turbulence needed to resuspend biosolids and to maintain them in the water column following different times of consolidation, and with biosolids of different origin, was analysed. It was observed that the turbulence needed to resuspend aquaculture biosolids increased with the time of consolidation. When the turbulence was decreased after a resuspension process, the next sedimentation of biosolids showed a hysteretic behaviour: turbulence needed to resuspend a fixed percent of biosolids from the tank bottom is substantially higher than that needed to maintain the same percentage suspended in the water column. Differences in resuspension behaviour of biosolids originated in different tanks were also observed. The method provides useful information that can be compared with turbulence generated by fish swimming activity, in order to determine the culture conditions, which can promote self-cleaning conditions in a particular tank.

    Menció d'Honor 2010 que atorga l'Aquacultural Engineering Society

  • Hidrodynamic characterisation of aquaculture tanks and design criteria for improving self-cleaning properters  Open access

     Masalo Llora, Ingrid
    Defense's date: 2008-09-10
    Department of Agri-Food Engineering and Biotechnology, Universitat Politècnica de Catalunya
    Theses

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    El propòsit del treball es caracteritzar hidrodinàmicament els tancs més utilitzats en el sector aqüícola, i donar pautes de disseny per millorar-ne l'autoneteja, i optimitzar l'eficiència d'utilització tant de l'espai com de l'aigua. La tesis es presenta en forma de compendi d'articles. En els dos primers s'estudien les característiques hidrodinàmiques de diferents configuracions geomètriques i diferents dissenys d'entrada d'aigua. En els dos últims s'estudien els processos de sedimentació i resuspenció dels biosolids que es generen en els tanc aqüícoles, mesurant la turbulència necessària per la sedimentació i resuspenció, i posteriorment es varen comparar els valors obtinguts amb els de la turbulència generada per la pròpia activitat natatòria del peixos en els tancs de cultiu.L'estudi de les característiques hidrodinàmiques dels tancs, es va realitzar amb models a escala al laboratori, que es van evaluar mitjançant velocimetria de seguiment de partícules. La turbulència generada pels peixos al nedar es va estudiar mitjançant velocimetria acústica, utilitzat la mitja quadràtica de les velocitats (Root Mean Square RMS) com a paràmetre per quantificar la turbulència. Finalment, la turbulència necessària per la resuspenció de biosolids es va determinar amb una graella oscil·lant adaptada a les característiques dels biosolids aqüícoles (alt contingut orgànic, i alta cohesivitat); l'RMS també fou el paràmetre utilitzat per quantificar la turbulència necessària per la resuspenció de biosolids.Amb l'estudi de les característiques hidrodinàmiques dels models a escala, s'ha determinat que el patró de flux està fortament condicionat pel disseny de l'entrada d'aigua. S'ha observat que en les configuracions on l'aigua fluïa de d'un extrem del tanc a l'altre, el patró de flux era molt heterogeni amb presència freqüent de zones mortes i corrents de curt-circuit. Les velocitats aconseguides foren baixes. Es van aconseguir velocitats més altes i una major homogeneïtat quan es va introduïr l'aigua tangencialment a la paret del tanc per tal de crear cèl·lules de barreja. Les cèl·lules de barreja van presentar un flux típic de tancs circulars tot i la geometria rectangular dels tancs utilitzats. Es va definir el paràmetre coeficient de resistència de tanc (Ct), que ha demostrat ser vàlid per evaluar tancs tant circulars com rectangulars amb cèl·lules de barreja. Aquest coeficient ha estat útil per evaluar l'efecte de l'emplaçament de bafles i de les diferents ratios entre longitud i amplada de cèl·lula estudiades. S'ha comprovat que l'efecte dels bafles augmenta les velocitats a la sortida de l'aigua. L'augment d'aquestes velocitats permetrà eliminar els biosòlids del tanc i aconseguir una millor autoneteja.Referent a l'estudi de l'activitat natatòria dels peixos mitjançant velocimetria acústica, el mètode proposat ha permès determinar que la turbulència generada pels peixos al nedar augmenta amb la densitat, així com l'important efecte que té el fotoperíode en l'activitat natatòria dels llobarros.Per últim, la utilització de la graella oscil·lant per determinar el nivell de turbulència necessari per resuspendre els biosolids i el nivell necessari per mantenir-los a la columna d'aigua, ha permès determinar l'efecte del temps de consolidació en la turbulència necessària per la resuspenció. També s'ha observat que existeix histèresis quan després d'un procés de resuspenció, la turbulència es va disminuir per evaluar el procés de sedimentació. Finalment, s'han pogut determinar diferències en la turbulència necessària per la resuspenció quan es van evaluar biosolids procedents de diferents tancs, amb diferents densitats de cultiu i talla de peixos.

    El propósito del presente trabajo es caracterizar hidrodinámicamente los tanques más utilizados en acuicultura y dar pautas de diseño para mejorar su autolimpieza, y optimizar la eficiencia de utilización tanto del espacio como del agua. La tesis se presenta en forma de compendio de artículos. En los dos primeros se estudiaron las características hidrodinámicas de diferentes configuraciones geométricas y diferentes diseños de entrada de agua. En los dos últimos artículos se estudiaron los procesos de sedimentación y resuspensión de los biosólidos que se generan en los tanques acuícolas, midiendo la turbulencia necesaria tanto para la sedimentación como para la resuspensión, y se compararon los valores obtenidos con los de la turbulencia generada por la propia actividad natatoria de los peces en los tanques de cultivo.El estudio de las características hidrodinámicas de los tanques se realizó con modelos a escala en laboratorio, que se evaluaron mediante velocimetría de seguimiento de partículas. La turbulencia generada por los peces al nadar se estudió mediante velocimetría acústica, siendo la media cuadrática de las velocidades (Root Mean Square RMS) el parámetro utilizado para cuantificar la turbulencia. Finalmente, la turbulencia necesaria para la resuspensión de biosólidos se determinó mediante una parrilla oscilante adaptada a las características de dichos biosólidos (alto contenido orgánico y alta cohesividad); el RMS también fue el parámetro utilizado para cuantificar la turbulencia necesaria para la sedimentación y resuspensión de biosólidos.En el estudio de las características hidrodinámicas de los modelos a escala, se ha determinado que el patrón de flujo está fuertemente condicionado por el diseño de entrada del agua. Se ha observado que en las configuraciones en que el agua fluyó des de un extremo del tanque al otro, el patrón de flujo fue heterogéneo con presencia frecuente de zonas muertas y corrientes de corto circuito. Las velocidades alcanzadas fueron bajas. Se consiguieron velocidades más altas y una mayor homogeneidad cuando el agua se introdujo tangencialmente a la pared del tanque para crear células de mezcla. Las células de mezcla presentaron un flujo típico de tanques circulares a pesar de la geometría rectangular del tanque. Se definió el parámetro coeficiente de resistencia de tanque (Ct), que ha demostrado ser válido para evaluar tanques tanto circulares como rectangulares con células de mezcla. Dicho coeficiente ha sido útil para poder evaluar el efecto del emplazamiento de bafles y de las diferentes ratios entre longitud y ancho de célula estudiadas. Se ha comprobado que el efecto de los bafles aumenta las velocidades en la salida del agua. El aumento de estas velocidades permitirá eliminar los biosólidos del tanque y alcanzar una mejor autolimpieza.Referente al estudio de la actividad natatoria de los peces mediante velocimetría acústica, el método propuesto ha permitido determinar que la turbulencia generada por los peces al nadar aumenta con la densidad, así como el fuerte efecto que tiene el fotoperíodo en la actividad natatoria de las lubinas.Por último, el uso de la parrilla oscilante para determinar el nivel de turbulencia necesario para resuspender biosólidos y el nivel necesario para mantenerlos en la columna de agua, ha permitido determinar el efecto del tiempo de consolidación en la turbulencia necesaria para la resuspensión. También se ha observado la existencia de histéresis cuando después de un proceso de resuspensión, la turbulencia se disminuyó para evaluar el proceso de sedimentación. Finalmente, se han podido determinar diferencias en la turbulencia necesaria para la resuspensión cuando se evaluaron biosólidos procedentes de diferentes tanques, con diferentes densidades de cultivo y talla de peces.

    The purpose of this work is to characterise the hydrodynamics of the most commonly used aquaculture tanks and to define design criteria that will improve self-cleaning properties and optimise the use of space and water. The dissertation is submitted as a compilation of individual articles. Two of the articles focus on the hydrodynamic characteristics of various tank geometries with different water inlet designs. The remaining articles examine the turbulence required for sedimentation and resuspension of biosolids generated in aquaculture tanks. The turbulence values obtained are compared with the turbulence generated by fish swimming activity in aquaculture tanks.Hydrodynamic characteristics were studied in the laboratory by applying particle-tracking velocimetry techniques to scale models.The turbulence generated by fish swimming activity was studied using acoustic velocimetry techniques and quantified using the root mean square (RMS) of velocities. Finally, the turbulence needed to resuspend biosolids was determined using an oscillating grid adapted to the specific characteristics of the aquaculture biosolids (high organic content and high cohesiveness); RMS was also used to quantify the turbulence needed to resuspend biosolids.Analysis of the hydrodynamic characteristics of scale models revealed that the flow pattern is strongly affected by the water inlet design. The flow pattern was homogeneous in configurations in which water flowed along the tank from the upper to the lower end, and dead zones and bypass currents were frequently observed. Flow velocities were low. The homogeneous flow pattern and higher water velocities were observed when water was injected tangentially to create a rotating flow pattern. Rotating flow cells produced a circular flow pattern in rectangular tanks. We defined a tank resistance coefficient (Ct), which was found to be suitable for evaluating both circular and rectangular tanks with rotating flow patterns. The coefficient was used to assess the effect of baffles and various length/width cell ratios. We found that baffles increased the water velocity at the outlets, which is important in the removal of biosolids and for producing self-cleaning properties.Acoustic velocimetry was used to study fish swimming activity. We found that the turbulence generated by swimming activity increases with density and that the photoperiod has a strong effect on the swimming activity of sea bass.Finally, an oscillating grid was used to determine the turbulence needed to resuspend biosolids and the turbulence needed to keep them in the water column; these experiments illustrated the effect of consolidation time on the turbulence required for resuspension.Hysteresis was observed when turbulence was reduced to evaluate sedimentation following resuspension, and different levels of turbulence were required for resuspension in different tanks (with different densities and fish sizes).

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    Avaluació de la preferència del llenguado (Solea senegalensis) per substrats de diferents textures i colors  Open access

     Duarte Ortega, Sonia; Reig Puig, Lourdes; Oca Baradad, Joan
    I Simposi d'Aqüicultura de Catalunya. Societat Catalana de Biologia
    Presentation's date: 2008
    Presentation of work at congresses

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  • Cuantificación de los procesos de resuspensión y sedimentación de biosólidos acuícolas

     Masalo Llora, Ingrid; Reig Puig, Lourdes; Oca Baradad, Joan
    International Workshop on Anaerobic Digestion of Slaughterhouse Waste
    Presentation of work at congresses

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  • Spatial fish distribution (Danio rerio) in a rectangular tank with different water inlet characteristics

     Duarte Ortega, Sonia; Reig Puig, Lourdes; Masalo Llora, Ingrid; Oca Baradad, Joan
    V Jornada de Doctorat. Tecnologia Agroalimentària i Biotecnologia
    Presentation of work at congresses

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  • Avaluació de la preferència del llenguado (Solea senegalensis) per substrats de diferents textures i colors

     Oca Baradad, Joan
    I Simposi d'Aqüicultura de Catalunya. Societat Catalana de Biologia
    Presentation's date: 2008-02-06
    Presentation of work at congresses

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  • Study of fish swimming activity using acoustical Doppler velocimetry (ADV) techniques

     Masalo Llora, Ingrid; Reig Puig, Lourdes; Oca Baradad, Joan
    Aquacultural engineering
    Date of publication: 2008-01
    Journal article

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    Design criteria for rotating flow cells in rectangular aquaculture tanks  Open access

     Masalo Llora, Ingrid; Oca Baradad, Joan
    Aquacultural engineering
    Date of publication: 2007-01
    Journal article

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  • Influencia de la presencia de peces planos en las características hidrodinámicas de tanques rectangulares

     Masalo Llora, Ingrid; Reig Puig, Lourdes; Oca Baradad, Joan
    IV Jornada de Doctorat. Programa Biotecnologia Agroalimentària i Sostenibilitat
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  • Gestión del Agua y Desarrollo Rural

     Oca Baradad, Joan
    Date of publication: 2007-01
    Book chapter

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  • A laser scanning method to evaluate flatfish distribution in a shallow raceway tank

     Duarte Ortega, Sonia; Oca Baradad, Joan; Reig Puig, Lourdes
    IV Jornada de Doctorat. Programa Biotecnologia Agroalimentària i Sostenibilitat
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  • Evaluation of spatial distribution of flatfish by laser scanning

     Oca Baradad, Joan
    Aquaculture Europe 2007
    Presentation's date: 2007-05-01
    Presentation of work at congresses

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  • A laser scanning method to evaluate flatfish distribution in a shallow raceway tank

     Oca Baradad, Joan
    IV Jornada de Doctorat. Programa Biotecnologia Agroalimentària i Sostenibilitat
    Presentation's date: 2007-07-03
    Presentation of work at congresses

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  • Evaluation of sole (Solea senegalensis) preferences for different substrate textures and colours

     Duarte Ortega, Sonia; Oca Baradad, Joan; Reig Puig, Lourdes
    Aquaculture Europe 2007
    Presentation of work at congresses

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  • Use of the tank resistance coefficient to evaluate modifications of water inlet devices in rotating flowtanks

     Masalo Llora, Ingrid; Oca Baradad, Joan
    Aquaculture Europe 2007
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  • Study of consecutive resuspension and sedimentation processes in aquacultural biosolids using an oscillating grid

     Masalo Llora, Ingrid; Reig Puig, Lourdes; Oca Baradad, Joan
    Aquaculture Europe 2007
    Presentation of work at congresses

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  • Estudi dels processos de resuspensió i sedimentació de biosòlids procedents de l'aqüicultura mitjançant la utilització d'una graella oscil.lant

     Masalo Llora, Ingrid; Reig Puig, Lourdes; Duarte Ortega, Sonia; Oca Baradad, Joan
    I Jornada de Recerca a l'ESAB. Tractament biològic de residus orgànics i la seva valorització
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  • Hierarquic structures of an heterobeneous size sole population determined by direct observation and computerised image analysis

     Duarte Ortega, Sonia; Reig Puig, Lourdes; Oca Baradad, Joan; Sanchez Fernandez, Pablo; Ambrosio, P P; Flos, F
    III Jornada de Doctorado "Biotecnología Agroalimentaria y Sostenibilidad"
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  • Biosolids resuspension in aquaculture tank is affected by disaggregation and consolidation time

     Masalo Llora, Ingrid; Guadayol, O; Peters, F; Oca Baradad, Joan
    World Aquaculture 2006 "Highest quality for the consumer"
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  • A hyperintensive fish farming concept of lasting competitiveness and superior production (RACEWAYS) - CRAFT-016869

     Oca Baradad, Joan; Reig Puig, Lourdes; Masalo Llora, Ingrid; Duarte Ortega, Sonia
    Participation in a competitive project

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  • Técnicas cualitativas y cuantitativas para determinar la resuspensión de biosólidos en una parrilla oscilante

     Masalo Llora, Ingrid; Oca Baradad, Joan
    III Jornada de Doctorat. Biotecnologia Agroalimentària i Sostenibilitat
    Presentation of work at congresses

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