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The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Fri, 23 Aug 2019 07:00:18 GMT2019-08-23T07:00:18ZFSI investigation on stability of downwind sails with an automatic dynamic trimming
http://hdl.handle.net/10985/9497
FSI investigation on stability of downwind sails with an automatic dynamic trimming
DURAND, Mathieu; LEROYER, Alban; LOTHODÉ, Corentin; HAUVILLE, Frédéric; VISONNEAU, MICHEL; FLOCH, Ronan; GUILLAUME, Laurent
Gennakers are lightweight and flexible sails, used for downwind sailing configurations. Qualities sought for this kind of sail are propulsive force and dynamic stability. To simulate accurately the flow surrounding a sail, several problems need to be solved. Firstly, the structural code has to take into account cloth behavior, orientation and reinforcements. Moreover, wrinkles need to be taken into account through modeling or fine enough discretization. Secondly, the fluid solver needs to reproduce the atmospheric boundary layer as an input boundary condition, and be able to simulate separation. Thirdly, the fluid-structure interaction (FSI) is strongly coupled due to the lightness and the flexibility of the structure. The added mass is three orders of magnitude greater than the mass of the sail, and large structural displacement occur, which makes the coupling between the two solvers difficult to achieve. Finally, the problem is unsteady, and dynamic trimming is important to the simulation of gennakers (Graf and Renzsch, 2006). As the FSI procedure is detailed in Durand (2012), the present work is rather focused on its application to downwind sail stability. The main objective of this paper is to use numerical simulations to model gennakers, in order to predict both propulsive force and sail dynamic stability. Recent developments from Durand (2012) are used to solve these problems mentioned earlier, using a finite element structural analysis program dedicated to sails and rig simulations coupled with an unsteady Reynolds averaged Navier–Stokes equations (URANSE) solver. The FSI coupling is done through a partitioned approach with quasi-monolithic properties. An arbitrary Lagrangian Eulerian (ALE) formulation is used, hence the fluid mesh follows the structural deformation while keeping the same topology. The fluid mesh deformation is carried out with a fast, robust and parallelized method based on the propagation of the deformation state of the sail boundary fluid faces (Durand et al., 2010). Tests were realized on a complete production chain: a sail designer from Incidences-Sails has designed two different shapes of an IMOCA60 gennaker with the SailPack software. An automatic procedure was developed to transfer data from Sailpack to a structure input file taking into account the orientation of sailcloth and reinforcements. The same automatic procedure is used for both gennakers, in order to compare dynamic stability and propulsion forces. A new method is then developed to quantify the practical stability of a downwind sail.
Wed, 01 Jan 2014 00:00:00 GMThttp://hdl.handle.net/10985/94972014-01-01T00:00:00ZDURAND, MathieuLEROYER, AlbanLOTHODÉ, CorentinHAUVILLE, FrédéricVISONNEAU, MICHELFLOCH, RonanGUILLAUME, LaurentGennakers are lightweight and flexible sails, used for downwind sailing configurations. Qualities sought for this kind of sail are propulsive force and dynamic stability. To simulate accurately the flow surrounding a sail, several problems need to be solved. Firstly, the structural code has to take into account cloth behavior, orientation and reinforcements. Moreover, wrinkles need to be taken into account through modeling or fine enough discretization. Secondly, the fluid solver needs to reproduce the atmospheric boundary layer as an input boundary condition, and be able to simulate separation. Thirdly, the fluid-structure interaction (FSI) is strongly coupled due to the lightness and the flexibility of the structure. The added mass is three orders of magnitude greater than the mass of the sail, and large structural displacement occur, which makes the coupling between the two solvers difficult to achieve. Finally, the problem is unsteady, and dynamic trimming is important to the simulation of gennakers (Graf and Renzsch, 2006). As the FSI procedure is detailed in Durand (2012), the present work is rather focused on its application to downwind sail stability. The main objective of this paper is to use numerical simulations to model gennakers, in order to predict both propulsive force and sail dynamic stability. Recent developments from Durand (2012) are used to solve these problems mentioned earlier, using a finite element structural analysis program dedicated to sails and rig simulations coupled with an unsteady Reynolds averaged Navier–Stokes equations (URANSE) solver. The FSI coupling is done through a partitioned approach with quasi-monolithic properties. An arbitrary Lagrangian Eulerian (ALE) formulation is used, hence the fluid mesh follows the structural deformation while keeping the same topology. The fluid mesh deformation is carried out with a fast, robust and parallelized method based on the propagation of the deformation state of the sail boundary fluid faces (Durand et al., 2010). Tests were realized on a complete production chain: a sail designer from Incidences-Sails has designed two different shapes of an IMOCA60 gennaker with the SailPack software. An automatic procedure was developed to transfer data from Sailpack to a structure input file taking into account the orientation of sailcloth and reinforcements. The same automatic procedure is used for both gennakers, in order to compare dynamic stability and propulsion forces. A new method is then developed to quantify the practical stability of a downwind sail.Unsteady numerical simulations of downwind sails
http://hdl.handle.net/10985/14896
Unsteady numerical simulations of downwind sails
DURAND, Mathieu; HAUVILLE, Frédéric; BOT, Patrick; AUGIER, Benoit; ROUX, Y; LEROYER, Alban; VISONNEAU, Michel
Modelling the wind, sail and rig interactions on a sailing yacht is a complex subject, because the quality of simulation depends on the accuracy of both structural and fluid simulations which strongly interact. Moreover, the sails are submitted to highly unsteady sollicitations due to waves, wind variations, course changes or trimming for example, but sometimes also due to the unsteadiness of the flow itself (vortex shedding,…). The problem for downwind sails is even more complex because the flow is often detached from the sails, and the sails are subject to large shape changes. A specific dynamic coupling has been developed between a RANSE code from Ecole Centrale de Nantes for the aerodynamics (ISIS-CFD) and a FEM code from K-Epsilon for the structure (ARA) specialized to simulate the aeroelastic problem of yacht sails and rig. In this paper, the particular issues of coupling, remeshing and transfer of forces from one code to the other are detailed. An experimental comparison is made on a well controlled test case with an original experiment developed by IRENav Ecole Navale, consisting in a square of spinnaker fabric mounted on two carbon battens which are moved in a forced oscillation. The good agreement of numerical results with experimentals results permits to be confident to go ahead and investigate a full example of application on a racing yacht spinnaker.
Fri, 01 Jan 2010 00:00:00 GMThttp://hdl.handle.net/10985/148962010-01-01T00:00:00ZDURAND, MathieuHAUVILLE, FrédéricBOT, PatrickAUGIER, BenoitROUX, YLEROYER, AlbanVISONNEAU, MichelModelling the wind, sail and rig interactions on a sailing yacht is a complex subject, because the quality of simulation depends on the accuracy of both structural and fluid simulations which strongly interact. Moreover, the sails are submitted to highly unsteady sollicitations due to waves, wind variations, course changes or trimming for example, but sometimes also due to the unsteadiness of the flow itself (vortex shedding,…). The problem for downwind sails is even more complex because the flow is often detached from the sails, and the sails are subject to large shape changes. A specific dynamic coupling has been developed between a RANSE code from Ecole Centrale de Nantes for the aerodynamics (ISIS-CFD) and a FEM code from K-Epsilon for the structure (ARA) specialized to simulate the aeroelastic problem of yacht sails and rig. In this paper, the particular issues of coupling, remeshing and transfer of forces from one code to the other are detailed. An experimental comparison is made on a well controlled test case with an original experiment developed by IRENav Ecole Navale, consisting in a square of spinnaker fabric mounted on two carbon battens which are moved in a forced oscillation. The good agreement of numerical results with experimentals results permits to be confident to go ahead and investigate a full example of application on a racing yacht spinnaker.FSI Investigation on Stability of Downwind Sails with an Automatic Dynamic Trimming
http://hdl.handle.net/10985/14917
FSI Investigation on Stability of Downwind Sails with an Automatic Dynamic Trimming
DURAND, Mathieu; LOTHODE, Corentin; HAUVILLE, Frédéric; LEROYER, Alban; VISONNEAU, Michel; FLOCH, Ronan; GUILLAUME, L
Gennakers are lightweight and flexible sails, used for downwind sailing configurations. Qualities sought for this kind of sail are propulsive force and dynamic stability. To simulate accurately the flow around such a sail, several problems need to be solved. Firstly, the structural code has to take into account cloth behavior, orientation and reinforcements. Flexibility is obtained by modeling wrinkles. Secondly, the fluid code needs to reproduce the atmospheric boundary layer as an input boundary condition, and be able to simulate separation. Thirdly, fluid-structure interaction (FSI) is strong due to the lightness and the flexibility of the structure. The added mass is three orders of magnitude greater than the mass of the sail, and large structural displacement occurs, which makes the coupling between the two solvers difficult to achieve. Finally, the problem is unsteady, and dynamic trimming is important to the simulation of spinnakers [4]. The main objective is to use numerical simulations to model spinnakers, in order to predict both propulsive force and sail dynamic stability. Recent developments [2] are used to solve these problems, using a finite element program dedicated to sails and rig simulations coupled with a RANSE solver. The FSI coupling is done through a quasi-monolithic method. An ALE formulation is used, hence the fluid mesh follows the structural deformation while keeping the same topology. The fluid mesh deformation is carried out with a fast, robust and parallelized method based on the propagation of the deformation state of the sail boundary fluid faces [3]. Tests are realized on a complete production chain: a sail designer from Incidences has designed two different shapes of an IMOCA60 spinnaker with the SailPack software. An automatic procedure was developed to transfer data from Sailpack to a structure input file taking into account the orientation of sailcloth and reinforcements. The same automatic procedure is used for both spinnakers, in order to compare dynamic stability and propulsion forces. Then a new method is developed to quantify the stability of a downwind sail.
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/10985/149172013-01-01T00:00:00ZDURAND, MathieuLOTHODE, CorentinHAUVILLE, FrédéricLEROYER, AlbanVISONNEAU, MichelFLOCH, RonanGUILLAUME, LGennakers are lightweight and flexible sails, used for downwind sailing configurations. Qualities sought for this kind of sail are propulsive force and dynamic stability. To simulate accurately the flow around such a sail, several problems need to be solved. Firstly, the structural code has to take into account cloth behavior, orientation and reinforcements. Flexibility is obtained by modeling wrinkles. Secondly, the fluid code needs to reproduce the atmospheric boundary layer as an input boundary condition, and be able to simulate separation. Thirdly, fluid-structure interaction (FSI) is strong due to the lightness and the flexibility of the structure. The added mass is three orders of magnitude greater than the mass of the sail, and large structural displacement occurs, which makes the coupling between the two solvers difficult to achieve. Finally, the problem is unsteady, and dynamic trimming is important to the simulation of spinnakers [4]. The main objective is to use numerical simulations to model spinnakers, in order to predict both propulsive force and sail dynamic stability. Recent developments [2] are used to solve these problems, using a finite element program dedicated to sails and rig simulations coupled with a RANSE solver. The FSI coupling is done through a quasi-monolithic method. An ALE formulation is used, hence the fluid mesh follows the structural deformation while keeping the same topology. The fluid mesh deformation is carried out with a fast, robust and parallelized method based on the propagation of the deformation state of the sail boundary fluid faces [3]. Tests are realized on a complete production chain: a sail designer from Incidences has designed two different shapes of an IMOCA60 spinnaker with the SailPack software. An automatic procedure was developed to transfer data from Sailpack to a structure input file taking into account the orientation of sailcloth and reinforcements. The same automatic procedure is used for both spinnakers, in order to compare dynamic stability and propulsion forces. Then a new method is developed to quantify the stability of a downwind sail.