FSI Investigation on Stability of Downwind Sails with an Automatic Dynamic Trimming
TypeCommunications avec actes
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 . The main objective is to use numerical simulations to model spinnakers, in order to predict both propulsive force and sail dynamic stability. Recent developments  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 . 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.
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DURAND, Mathieu; LEROYER, Alban; LOTHODÉ, Corentin; HAUVILLE, Frédéric; VISONNEAU, MICHEL; FLOCH, Ronan; GUILLAUME, Laurent (ELSEVIER, 2014)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, ...
DURAND, Mathieu; HAUVILLE, Frédéric; BOT, Patrick; AUGIER, Benoit; ROUX, Y; LEROYER, Alban; VISONNEAU, Michel (Royal Institution of Naval Architects, 2010)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, ...
AUBIN, Nicolas; AUGIER, Benoit; BOT, Patrick; HAUVILLE, Frédéric; FLOCH, Ronan (Elsevier, 2016)This work presents a full-scale experimental study of a yacht rig and sails in real upwind sailing conditions and a comparison with Fluid Structure Interaction (FSI) simulations with the ARAVANTI model (Finite Element ...
AUGIER, Benoit; BOT, Patrick; HAUVILLE, Frédéric; DURAND, Mathieu (Editions de l'Ecole Polytechnique, 2013)The dynamic Fluid Structure Interaction (FSI) of yacht sails submitted to a harmonic pitching motion is numerically investigated to address both issues of aerodynamic unsteadiness and structural deformation. The model ...
Numerical study of a Flexible Sail Plan submitted to pitching : Hysteresis phenomenon and effect of rig Adjustments AUGIER, Benoit; HAUVILLE, Frédéric; BOT, Patrick; AUBIN, Nicolas; DURAND, Mathieu (Elsevier, 2014)A numerical investigation of the dynamic Fluid Structure Interaction (FSI) of a yacht sail plan submitted to harmonic pitching is presented to analyse the system's dynamic behaviour and the effects of motion simplifications ...