Experimental validation of unsteady models for fluid structure interaction: Application to yacht sails and rigs

Abstract

This work presents a full scale experimental study on the aero-elastic wind/sails/rig interaction in real navigation conditions with the aim to give an experimental validation of unsteady Fluid Structure Interaction (FSI) models applied to yacht sails. An inboard instrumentation system has been developed on a J80 yacht to simultaneously and dynamically measure the navigation parameters, yacht's motion, and sails flying shape and loads in the standing and running rigging. The first results recorded while sailing upwind in head waves are shown. Variations of the measured parameters are characterized and related to the yacht motion (trim mainly). Correlations between the different parameters are examined. In the system's response to the dynamic forcing (pitching motion) we attempt to distinguish between the aerodynamic effect of varying apparent wind induced by the motion and the structural effect of varying stresses and strains due to the motion and inertia. The dynamic full scale measurements presented underline the necessity of considering the unsteadiness of phenomena to correctly simulate a yacht's behavior in actual sailing conditions. The simulation results from the FSI model compare very well with the experimental data for steady sailing conditions. For the unsteady conditions obtained in head waves, the first results show a good agreement between measurements and simulation.

Experimental investigation of asymmetric spinnaker aerodynamics using pressure and sail shape measurements

“…Full-scale testing is usually required to validate results from these methods. Moreover, fullscale testing allows the investigation of yacht performance in real sailing conditions, quantification of the actual forces at work (Le Pelley et al, 2012;Lozej et al, 2012;Augier et al, 2012) and, for example, studies of the effects of the rigging on yacht performance (Augier et al, 2012;Bergsma et al, 2012aBergsma et al, , 2012b. Several fullscale sail pressure measurements have been carried out in recent years (Lozej et al, 2012;Viola andFlay, 2010b, 2011;Graves et al, 2008;Puddu et al, 2006).…”

Inviscid approach for upwind sails aerodynamics. How far can we go?

“…A specific instrumentation described in Augier et al (2012) is used to measure the loads in 16 points of the rig, the yacht motion and attitudes, the sails flying shape and navigation parameters. Mainsail and jib luffs are hanked on, foots and leeches are loose.…”

“…More details about the coupling scheme can be found in Roux et al (2008). The ability of ARAVANTI to accurately predict aerodynamic loads and the flying shape of the sails in both steady and unsteady situations has been shown in Augier et al (2012).…”

“…For instance Yoo and Kim (2006) compared CFD results and experimental measurements on yacht sails. IRENav has validated a numerical FSI model with full-scale results achieved on an instrumented J80-class yacht (Augier, 2012;Augier et al, 2012) in both steady and unsteady situations. The model was then used to predict the aerodynamic forces and rig loads of a sailing yacht in dynamic conditions (Augier et al, 2014) and can be used for performance studies.…”

A Parallel Fully Coupled Approach for Large-Scale Fluid-Structure Interaction Problems

“…The FSI problem is mainly characterized by the mutual interaction between a movable or deformable structure with an internal or surrounding fluid flow. Typical examples in engineering applications involve aeroelastic phenomena like flutter of aircraft wings [1,2] or turbine blades [3] and tail buffeting [4], inflation of parachutes [5] or airbags [6], design of sails [7] or tent structures [8], structural effect of strong wind on bridges [9] and tall buildings [10], and many others. On the other hand, much of the work in biomedical applications include blood flow in the veins and arteries [11], dynamics of heart valves [12,13], deformations and aggregations of blood cells [14,15].…”