https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Thu, 12 Mar 2026 13:48:09 GMT 2026-03-12T13:48:09Z http://hdl.handle.net/10985/6724 Numerical study of cavitating flow inside a flush valve DUTHEIL, Daniel; CAIGNAERT, Guy; SIMONET, Sophie; BAYEUL-LAINÉ, Annie-Claude In water supply installations, noise pollution often occurs. As a basic component of a system, a flush valve may frequently be a source of noise and vibration generated by cavitation or high turbulence levels. During valve closing or valve opening, cavitation can be a problem. In order to decrease the noise and to improve the design inside a flush valve, some experimental and numerical analyses were carried out in our laboratories. These analyses led to some improvements in the design of the valves. Cavitation occurrence was more specifically addressed, using numerical simulation, and this is the main aim of the present paper. Particularly, the use of a simplified numerical test without cavitation model is compared with one using a cavitation model. In order to define potential cavitation risks in some parts of the valve, it has been found that a simplified approach provides an accurate overview. Computational Fluid Dynamics (CFD) simulations of cavitating flow of water through an industrial flush valve were performed using the Reynolds averaged Navier-Stokes (RANS) equations with a near-wall turbulence model. The flow was assumed turbulent, incompressible and steady. Two commercial CFD codes (Fluent 6.3 and Star CCM+ 3.04.009) were used to analyse the effects of inlet pressure as well as mesh size and mesh type on cavitation intensity in the flush valve. Sat, 01 Jan 2011 00:00:00 GMT http://hdl.handle.net/10985/6724 2011-01-01T00:00:00Z DUTHEIL, Daniel CAIGNAERT, Guy SIMONET, Sophie BAYEUL-LAINÉ, Annie-Claude In water supply installations, noise pollution often occurs. As a basic component of a system, a flush valve may frequently be a source of noise and vibration generated by cavitation or high turbulence levels. During valve closing or valve opening, cavitation can be a problem. In order to decrease the noise and to improve the design inside a flush valve, some experimental and numerical analyses were carried out in our laboratories. These analyses led to some improvements in the design of the valves. Cavitation occurrence was more specifically addressed, using numerical simulation, and this is the main aim of the present paper. Particularly, the use of a simplified numerical test without cavitation model is compared with one using a cavitation model. In order to define potential cavitation risks in some parts of the valve, it has been found that a simplified approach provides an accurate overview. Computational Fluid Dynamics (CFD) simulations of cavitating flow of water through an industrial flush valve were performed using the Reynolds averaged Navier-Stokes (RANS) equations with a near-wall turbulence model. The flow was assumed turbulent, incompressible and steady. Two commercial CFD codes (Fluent 6.3 and Star CCM+ 3.04.009) were used to analyse the effects of inlet pressure as well as mesh size and mesh type on cavitation intensity in the flush valve. http://hdl.handle.net/10985/6726 Numerical simulation in vertical wind axis turbine with pitch controlled blades DOCKTER, Aurore; BOIS, Gérard; SIMONET, Sophie; BAYEUL-LAINÉ, Annie-Claude Wind energy is more and more used as a renewable energy source character. The present wind turbine is a small one which allows to be used on roofs or in gardens to light small areas like publicity boards, parking, roads or for water pumping, heating... The present turbine has a vertical axis. Each turbine blade combines a rotating movement around its own axis and around the main rotor axis. Due to this combination of movements, flow around this turbine is highly unsteady and needs to be modeled by unsteady calculation. One of the main problems of such geometry is to simulate the two combined movements. The present work is an extended study of one’s made in 2009. In the previous study, some results like contours of pressure and velocity fields were presented for elliptic blades for one specific constant rotational speed and benefits of combined rotating blades was shown. The present paper points up the influence of two different blades geometries for different rotational speeds, different blade stagger angles and different Reynolds numbers related to a wider range of wind speeds. Sun, 01 Jan 2012 00:00:00 GMT http://hdl.handle.net/10985/6726 2012-01-01T00:00:00Z DOCKTER, Aurore BOIS, Gérard SIMONET, Sophie BAYEUL-LAINÉ, Annie-Claude Wind energy is more and more used as a renewable energy source character. The present wind turbine is a small one which allows to be used on roofs or in gardens to light small areas like publicity boards, parking, roads or for water pumping, heating... The present turbine has a vertical axis. Each turbine blade combines a rotating movement around its own axis and around the main rotor axis. Due to this combination of movements, flow around this turbine is highly unsteady and needs to be modeled by unsteady calculation. One of the main problems of such geometry is to simulate the two combined movements. The present work is an extended study of one’s made in 2009. In the previous study, some results like contours of pressure and velocity fields were presented for elliptic blades for one specific constant rotational speed and benefits of combined rotating blades was shown. The present paper points up the influence of two different blades geometries for different rotational speeds, different blade stagger angles and different Reynolds numbers related to a wider range of wind speeds. http://hdl.handle.net/10985/6731 Spectral analysis of unsteady flow simulation in a small VAWT BOIS, Gérard; SIMONET, Sophie; BAYEUL-LAINÉ, Annie-Claude The vertical axis wind turbine studied in this paper combine two rotations: one rotating movement of each blade around its own axis and one rotating movement around turbine’s axis. The aim of this paper is to analyse the effect of this two combine movements on fields of pressure and on global forces on each blade with time. Preliminary calculations showed, for some initial blade stagger angles (angle between blade 1 and x axis), that flow is highly unsteady and sometimes hardly periodic. The main goal here is to present spectral analysis of unsteady results like temporal pressure on specific points in the domain and temporal forces on blades and to show the influence of the two combine movements for two different blade stagger angles for elliptic blades. Sun, 01 Jan 2012 00:00:00 GMT http://hdl.handle.net/10985/6731 2012-01-01T00:00:00Z BOIS, Gérard SIMONET, Sophie BAYEUL-LAINÉ, Annie-Claude The vertical axis wind turbine studied in this paper combine two rotations: one rotating movement of each blade around its own axis and one rotating movement around turbine’s axis. The aim of this paper is to analyse the effect of this two combine movements on fields of pressure and on global forces on each blade with time. Preliminary calculations showed, for some initial blade stagger angles (angle between blade 1 and x axis), that flow is highly unsteady and sometimes hardly periodic. The main goal here is to present spectral analysis of unsteady results like temporal pressure on specific points in the domain and temporal forces on blades and to show the influence of the two combine movements for two different blade stagger angles for elliptic blades. http://hdl.handle.net/10985/6725 Etude numérique instationnaire d'une micro-éolienne à axe vertical BAYEUL-LAINÉ, Annie-Claude; BOIS, Gérard; SIMONET, Sophie Bien que les éoliennes soient une forme très ancienne d’exploitation du vent, ces dernières quarante dernières années ont vu leur évolution et un développement important de leur conception dans le cadre du développement durable. Le présent article propose de présenter le résultat d’une collaboration entre le Laboratoire de Mécanique de Lille et une entreprise en cours de développement Windisplay. Cette entreprise est à l’origine de la création d’une éolienne, support d’affichage publicitaire original. L’intérêt de ce type de support est de fournir un éclairage d’origine éolienne au support publicitaire. L’originalité de cette turbine est la rotation de chaque pale autour de son propre axe qui permet une surface d’affichage deux fois plus grande, mais qui améliore également les performances d’une telle éolienne. De par cette combinaison de mouvements, l’écoulement autour de cette éolienne est fortement instationnaire et nécessite une modélisation adaptée, en particulier pour tenir compte des positions initiales des pales. Le but est de présenter cette modélisation et de donner un certain nombre de résultats tels que des cartes instantanées de vecteurs vitesse ou des contours de pression, mais aussi des résultats plus globaux tels que des couples ou des coefficients de performance. Fri, 01 Jan 2010 00:00:00 GMT http://hdl.handle.net/10985/6725 2010-01-01T00:00:00Z BAYEUL-LAINÉ, Annie-Claude BOIS, Gérard SIMONET, Sophie Bien que les éoliennes soient une forme très ancienne d’exploitation du vent, ces dernières quarante dernières années ont vu leur évolution et un développement important de leur conception dans le cadre du développement durable. Le présent article propose de présenter le résultat d’une collaboration entre le Laboratoire de Mécanique de Lille et une entreprise en cours de développement Windisplay. Cette entreprise est à l’origine de la création d’une éolienne, support d’affichage publicitaire original. L’intérêt de ce type de support est de fournir un éclairage d’origine éolienne au support publicitaire. L’originalité de cette turbine est la rotation de chaque pale autour de son propre axe qui permet une surface d’affichage deux fois plus grande, mais qui améliore également les performances d’une telle éolienne. De par cette combinaison de mouvements, l’écoulement autour de cette éolienne est fortement instationnaire et nécessite une modélisation adaptée, en particulier pour tenir compte des positions initiales des pales. Le but est de présenter cette modélisation et de donner un certain nombre de résultats tels que des cartes instantanées de vecteurs vitesse ou des contours de pression, mais aussi des résultats plus globaux tels que des couples ou des coefficients de performance. http://hdl.handle.net/10985/6727 Numerical study of flow stream in a mini VAWT with relative rotating blades DOCKTER, Aurore; BOIS, Gérard; SIMONET, Sophie; BAYEUL-LAINÉ, Annie-Claude Today, wind energy is mainly used to generate electricity and more and more with a renewable energy source character. Power production from wind turbines is affected by several conditions like wind speed, turbine speed, turbine design, turbulence and changes of wind direction. These conditions are not always optimal and have negative effects on most turbines. The present turbine is supposed to be less affected by these conditions because the blades combine a rotating movement around each own axis and around the main turbine’s one. Due to this combination of movements, flow around this turbine can be more optimized than classical Darrieus turbines. The turbine has a rotor with three straight blades of symmetrical aerofoil. Paper presents unsteady simulations that have been performed for one wind velocity and different blades stagger angles. The influence of two different blades geometry is studied for four different constant rotational speeds. Sat, 01 Jan 2011 00:00:00 GMT http://hdl.handle.net/10985/6727 2011-01-01T00:00:00Z DOCKTER, Aurore BOIS, Gérard SIMONET, Sophie BAYEUL-LAINÉ, Annie-Claude Today, wind energy is mainly used to generate electricity and more and more with a renewable energy source character. Power production from wind turbines is affected by several conditions like wind speed, turbine speed, turbine design, turbulence and changes of wind direction. These conditions are not always optimal and have negative effects on most turbines. The present turbine is supposed to be less affected by these conditions because the blades combine a rotating movement around each own axis and around the main turbine’s one. Due to this combination of movements, flow around this turbine can be more optimized than classical Darrieus turbines. The turbine has a rotor with three straight blades of symmetrical aerofoil. Paper presents unsteady simulations that have been performed for one wind velocity and different blades stagger angles. The influence of two different blades geometry is studied for four different constant rotational speeds. http://hdl.handle.net/10985/15495 Ventilation rates and thermal comfort assessment in a naturally ventilated classroom ALLAB, Yacine; KINDINIS, Andrea; CAUSONE, Francesco; TATTI, Anita; SIMONET, Sophie; BAYEUL-LAINÉ, Annie-Claude Ventilation systems are meant (i) to guarantee good indoor air quality (IAQ) by providing and distributing fresh air to the occupied/breathing zone and (ii) to dilute and remove pollutants emitted by indoor sources. On the other hand, inadequate ventilation rates can induce discomfort issues and excessive energy consumption. This study focuses on the performance assessment of natural ventilation strategies in university classrooms, which are characterized by a high occupancy level and the necessity to provide high levels of comfort to perform intellectual work. The high occupancy level creates challenging conditions both in terms of internal gains and CO2 concentration. This paper presents an experimental performance assessment of four natural ventilation strategies applied to a university classroom: single side ventilation, cross ventilation, stack ventilation with and without window supply. Each strategy is evaluated in terms of thermal comfort and air change rate measurements. Thermal comfort assessment were performed during occupancy period (physical parameter measurements and questionnaires) whereas air change rate measurements, based on tracer gas techniques, were performed during unoccupied periods. Fri, 01 Jan 2016 00:00:00 GMT http://hdl.handle.net/10985/15495 2016-01-01T00:00:00Z ALLAB, Yacine KINDINIS, Andrea CAUSONE, Francesco TATTI, Anita SIMONET, Sophie BAYEUL-LAINÉ, Annie-Claude Ventilation systems are meant (i) to guarantee good indoor air quality (IAQ) by providing and distributing fresh air to the occupied/breathing zone and (ii) to dilute and remove pollutants emitted by indoor sources. On the other hand, inadequate ventilation rates can induce discomfort issues and excessive energy consumption. This study focuses on the performance assessment of natural ventilation strategies in university classrooms, which are characterized by a high occupancy level and the necessity to provide high levels of comfort to perform intellectual work. The high occupancy level creates challenging conditions both in terms of internal gains and CO2 concentration. This paper presents an experimental performance assessment of four natural ventilation strategies applied to a university classroom: single side ventilation, cross ventilation, stack ventilation with and without window supply. Each strategy is evaluated in terms of thermal comfort and air change rate measurements. Thermal comfort assessment were performed during occupancy period (physical parameter measurements and questionnaires) whereas air change rate measurements, based on tracer gas techniques, were performed during unoccupied periods. http://hdl.handle.net/10985/22617 Numerical investigation of hemolysis phenomena in the FDA nozzle benchmark : mind the extensional stresses MAGHOULI, Ali; BAYEUL-LAINÉ, Annie-Claude; SIMONET, Sophie; HADDADI, Mohammad; COUTIER-DELGOSHA, Olivier In recent years, the idea of using a pump as a left ventricle assist device is being well developed by several groups. Meanwhile, one of the challenges in this field is the occurrence of biological phenomena such as hemolysis. From an engineering point of view, a solution to this problem is to provide an accurate and efficient numerical method to predict the phenomenon. Hemolysis models are typically based on equivalent scalar stress and exposure time. This paper aims to study the impact of considering extensional stresses as the main reason for hemolysis in the FDA Nozzle benchmark. The idea comes from an experimental article. First of all, flow’s hemodynamic was validated by comparing the results of normalized axial velocity in several sections with the experimental data. In this case, three different RANS models k− , k−ω and k−ω SST were employed. As expected, it is clear that the k−ω SST is the most accurate model. In the next step, hemolysis simulations performed for different equivalent stresses. In this case, the impact of scaling up the extensional stresses on predicted hemolysis is studied by adding a coefficient Cn to equivalent stress. It is concluded that by applying these new modifications the hemolysis index would be in a reliable range. Wed, 01 Jun 2022 00:00:00 GMT http://hdl.handle.net/10985/22617 2022-06-01T00:00:00Z MAGHOULI, Ali BAYEUL-LAINÉ, Annie-Claude SIMONET, Sophie HADDADI, Mohammad COUTIER-DELGOSHA, Olivier In recent years, the idea of using a pump as a left ventricle assist device is being well developed by several groups. Meanwhile, one of the challenges in this field is the occurrence of biological phenomena such as hemolysis. From an engineering point of view, a solution to this problem is to provide an accurate and efficient numerical method to predict the phenomenon. Hemolysis models are typically based on equivalent scalar stress and exposure time. This paper aims to study the impact of considering extensional stresses as the main reason for hemolysis in the FDA Nozzle benchmark. The idea comes from an experimental article. First of all, flow’s hemodynamic was validated by comparing the results of normalized axial velocity in several sections with the experimental data. In this case, three different RANS models k− , k−ω and k−ω SST were employed. As expected, it is clear that the k−ω SST is the most accurate model. In the next step, hemolysis simulations performed for different equivalent stresses. In this case, the impact of scaling up the extensional stresses on predicted hemolysis is studied by adding a coefficient Cn to equivalent stress. It is concluded that by applying these new modifications the hemolysis index would be in a reliable range. http://hdl.handle.net/10985/7254 VAWT with controlled blades : influence of wake of one turbine on power coefficient on the next turbine BOIS, Gérard; SIMONET, Sophie; BAYEUL-LAINÉ, Annie-Claude Power production from wind turbines is affected by several conditions like wind speed, turbine speed, turbine design, turbulence, changes of wind direct ion, wake of previous turbines. These conditions are not always optimal and have negative effects on most turbines. The present wind turbine is a small one which allows to be used on roofs or in gardens to light small areas like publicity boards, parkings, roads or for water pumping, heating... This turbine is less affected by these conditions because the blades combine a rotating movement around each own axis and around the main turbine’ s one. Due to this combination of movements, flow around this turbine is more optimized than classical Darrieus turbines. It has been shown in previous studies that the best configuration was obtained with straight blades, a blade stager angle comprised between 0 and 8 degrees and a range of non-dimensional velocity from 0.4 to 0.6 for a very good power coefficient of about 0.4 in case of one VAWT. The present study points up the influence of the position of each VAWT in a group of three turbines and of the distances between turbines. It deals on global and local performances of these turbines. Tue, 01 Jan 2013 00:00:00 GMT http://hdl.handle.net/10985/7254 2013-01-01T00:00:00Z BOIS, Gérard SIMONET, Sophie BAYEUL-LAINÉ, Annie-Claude Power production from wind turbines is affected by several conditions like wind speed, turbine speed, turbine design, turbulence, changes of wind direct ion, wake of previous turbines. These conditions are not always optimal and have negative effects on most turbines. The present wind turbine is a small one which allows to be used on roofs or in gardens to light small areas like publicity boards, parkings, roads or for water pumping, heating... This turbine is less affected by these conditions because the blades combine a rotating movement around each own axis and around the main turbine’ s one. Due to this combination of movements, flow around this turbine is more optimized than classical Darrieus turbines. It has been shown in previous studies that the best configuration was obtained with straight blades, a blade stager angle comprised between 0 and 8 degrees and a range of non-dimensional velocity from 0.4 to 0.6 for a very good power coefficient of about 0.4 in case of one VAWT. The present study points up the influence of the position of each VAWT in a group of three turbines and of the distances between turbines. It deals on global and local performances of these turbines. http://hdl.handle.net/10985/7624 The importance of the knowledge of flow stream in water sump pump ISSA, Abir; BOIS, Gérard; SIMONET, Sophie; BAYEUL-LAINÉ, Annie-Claude Numerous different experimental and numerical methods have been developed and are already improved in order to get rather good flow descriptions inside pump components. These calculations are generally realized assuming uniform and steady flow conditions, in particular for the inlet conditions. However, few studies are devoted to non-uniform upstream conditions, especially in case of water pump sump before entering the pump inlet tube. Free air-core vortex occurring at the water-intake pipe is an important problem encountered in hydraulic engineering because they reduce pump performances and may have large effects on the operating conditions. The paper deals with flow pattern inside sump pump. Experiments were conducted in order to select best positions of the suction pipe of water-intake specific configurations. The numerical studies try to reproduce the flow pattern of these experiments and confirm the influence of geometrical parameters on the flow structure in such a sump. These numerical studies points out the need of unsteady calculation in order to get a better understanding of flow behaviour including two-phases flow models. Tue, 01 Jan 2013 00:00:00 GMT http://hdl.handle.net/10985/7624 2013-01-01T00:00:00Z ISSA, Abir BOIS, Gérard SIMONET, Sophie BAYEUL-LAINÉ, Annie-Claude Numerous different experimental and numerical methods have been developed and are already improved in order to get rather good flow descriptions inside pump components. These calculations are generally realized assuming uniform and steady flow conditions, in particular for the inlet conditions. However, few studies are devoted to non-uniform upstream conditions, especially in case of water pump sump before entering the pump inlet tube. Free air-core vortex occurring at the water-intake pipe is an important problem encountered in hydraulic engineering because they reduce pump performances and may have large effects on the operating conditions. The paper deals with flow pattern inside sump pump. Experiments were conducted in order to select best positions of the suction pipe of water-intake specific configurations. The numerical studies try to reproduce the flow pattern of these experiments and confirm the influence of geometrical parameters on the flow structure in such a sump. These numerical studies points out the need of unsteady calculation in order to get a better understanding of flow behaviour including two-phases flow models. http://hdl.handle.net/10985/9565 URANS flow stream in a small VAWT SIMONET, Sophie; BAYEUL-LAINÉ, Annie-Claude Wind energy is mainly used to generate electricity and more and more with a renewable energy source character. Power production from wind turbines is affected by several conditions like wind speed, turbine speed, turbine design, turbulence, changes of wind direction, wake of previous turbines. These conditions are not always optimal and have negative effects on most turbines. The present wind turbine is a small one which allows to be used on roofs or in gardens to light small areas like publicity boards, parking, roads or for water pumping, heating... This turbine is less affected by these conditions because the blades combine a rotating movement around each own axis and around the main turbine’s one. Due to this combination of movements, flow around this turbine is more optimized than classical VAWT turbines. The turbine has a rotor with three straight blades of symmetrical aerofoil. The paper presents unsteady simulations that have been performed with this turbine .It points up the influence of two different blades geometries for different rotational speeds, different blade stagger angles and different Reynolds numbers related to a wider range of wind speeds. Thu, 01 Jan 2015 00:00:00 GMT http://hdl.handle.net/10985/9565 2015-01-01T00:00:00Z SIMONET, Sophie BAYEUL-LAINÉ, Annie-Claude Wind energy is mainly used to generate electricity and more and more with a renewable energy source character. Power production from wind turbines is affected by several conditions like wind speed, turbine speed, turbine design, turbulence, changes of wind direction, wake of previous turbines. These conditions are not always optimal and have negative effects on most turbines. The present wind turbine is a small one which allows to be used on roofs or in gardens to light small areas like publicity boards, parking, roads or for water pumping, heating... This turbine is less affected by these conditions because the blades combine a rotating movement around each own axis and around the main turbine’s one. Due to this combination of movements, flow around this turbine is more optimized than classical VAWT turbines. The turbine has a rotor with three straight blades of symmetrical aerofoil. The paper presents unsteady simulations that have been performed with this turbine .It points up the influence of two different blades geometries for different rotational speeds, different blade stagger angles and different Reynolds numbers related to a wider range of wind speeds.