Modelling leading edge separation on a flat plate and yacht sails using LES

Recent Advances in Numerical and Experimental Downwind Sail Aerodynamics

“…As noted by Flay et al (2017), this observation is supported by evidence of an LSB farther downstream along the chord. For example, Martin (2015), Flay et al (2017) and Nava et al (2017) have shown a clear LSB towards the rear of a circular arc, especially for a low AoA (lesser than the ideal one), and low Reynolds number. The sudden change occurring below and above a specific critical Reynolds number was discussed by Flay et al (2017).…”

“…The grid and time resolution required to apply an LES model is significantly higher to that of DES, and is unachievable even by very large supercomputers. However, some under-resolved simulations have been performed with some degree of success both for upwind (Nava et al, 2017) and downwind (Nava et al, 2018) sails. Nava et al (2017) undertook LES of upwind sails and flat plates, where the latter investigation is based on the low-Reynolds number experimental work of Crompton & Barrett (2000) that has often been used as a benchmark for low-camber sails (Collie, 2006;Collie et al, 2008).…”

“…However, some under-resolved simulations have been performed with some degree of success both for upwind (Nava et al, 2017) and downwind (Nava et al, 2018) sails. Nava et al (2017) undertook LES of upwind sails and flat plates, where the latter investigation is based on the low-Reynolds number experimental work of Crompton & Barrett (2000) that has often been used as a benchmark for low-camber sails (Collie, 2006;Collie et al, 2008). A key advantage of LES over RANS was originally shown by Sampaio et al (2014) and confirmed by Nava et al (2017) on upwind sails: the ability to predict the second recirculation bubble typical of long leading-edge bubbles.…”

Aerodynamic interference of yachts sailing upwind on opposite tacks

“…In this study yachts sailing upwind are modelled using the RANS CFD code ANSYS CFX. The model is validated against published experimental data for a rigid sail model of the yacht( [4,13]) which has previously been used to validate RANS ( [12], [7]) models. The apparent motion between two yachts on opposite tacks is reproduced by having the yachts modelled in two separate meshes that move with respect to each other.…”

Large Eddy Simulation of an asymmetric spinnaker

“…Sampaio's investigation is particularly relevant to modelling sailing yacht aerodynamics, since the flat plate leading edge separation bubble is similar to the separation bubble forming at the leading edge (or luff) of sails. Nava et al [12] applied LES to the modelling of an experiment of upwind sailing, showing the superior ability of LES compared to RANS in predicting the leading edge structures formed at the luff of the sails, and reproducing the experimental pressure distribution, particularly at the head of the mainsail.…”