High Froude Number Experimental Investigation of the 2DOF Behavior of a Multihull Float in Head Waves
Communication avec acte
Dynamic Velocity Prediction Programs are taking an increasingly prominent role in high performance yacht design, as they allow to deal with seakeeping abilities and stability issues. Their validation is however often neglected for lack of time and data. This paper presents an experimental campaign carried out in the towing tank of the Ecole Centrale de Nantes, France, to validate the hull modeling in use in a previously presented Dynamic Velocity Prediction Program. Even though with foils, hulls are less frequently immersed, a reliable hull modeling is necessary to properly simulate the critical transient phases such as touchdowns and takeoffs. The model is a multihull float with a waterline length of 2:5 m. Measurements were made in head waves in both captive and semi-captive conditions (free to heave and pitch), with the model towed at constant yaw and speed. To get as close as possible to real sailing conditions, experiments were made at both zero and non-zero leeway angles, sweeping a wide range of speed values, with Froude numbers up to 1:2. Both linear and nonlinear wave conditions were studied in order to test the limits of the modeling approach, with wave steepness reaching up to 7% in captive conditions and 3:5% in semicaptive ones. The paper presents the design and methodology of the experiments, as well as comparisons of measured loads and motions with simulations. Loads are shown to be consistent, with a good representation of the sustained non-linearities. Pitch and heave motions depict an encouraging correlation which confirms that the modeling approach is valid.
Showing items related by title, author, creator and subject.
High Froude Number Experimental Investigation of the 2 DOF Behavior of a Multihull Float in Head Waves Article dans une revue avec comité de lectureKERDRAON, Paul; HOREL, Boris; BOT, Patrick; LETOURNEUR, Adrien; DAVID LE TOUZÉ, David (The Society of Naval Architects and Marine Engineers, 2021)Dynamic Velocity Prediction Programs are taking an increasingly prominent role in high performance yacht design, as they allow to deal with seakeeping abilities and stability issues. Their validation is however often ...
Article dans une revue avec comité de lectureKERDRAON, Paul; HOREL, Boris; BOT, Patrick; LETOURNEUR, Adrien; LE TOUZÉ, David (Elsevier, 2020)Thanks to high lift-to-drag ratios, hydrofoils are of great interest for high-speed vessels. Modern sailing yachts fitted with foils have thus reached impressively high speeds on the water. But this hydrodynamic efficiency ...
Communication avec acteKERDRAON, Paul; HOREL, Boris; BOT, Patrick; LETOURNEUR, Adrien; LE TOUZÉ, David (SNAME, 2019-03)While in recent years the use of hydrofoils has experienced a substantial growth, traditional design tools such as Velocity Prediction Programs (VPP) have proven inadequate to help architects and engineers with performance ...
Communication avec acteDEPARDAY, Julien; BOT, Patrick; HAUVILLE, Frédéric; AUGIER, Benoit; RABAUD, Marc; MOTTA, Dario; LE PELLEY, David (2016)While sailing offwind, the trimmer typically adjusts the downwind sail "on the verge of luffing", letting occasionally the luff of the sail flapping. Due to the unsteadiness of the spinnaker itself, maintaining the luff ...
Experimental Investigation of Asymmetric Spinnaker Aerodynamics Using Pressure and Sail Shape Measurements Article dans une revue avec comité de lectureMOTTA, Dario; FLAY, Richard G.J.; RICHARDS, P.J.; LE PELLEY, David; DEPARDAY, Julien; BOT, Patrick (Elsevier, 2014)An innovative method combining simultaneous on-water pressure and sail shape measurements for determining aerodynamic forces produced by sails is described and used on Stewart 34 and J80 Class yachts flying asymmetric ...