The proposed project aims to investigate the fluid dynamics of yacht sails. Sails have unique flow features, which allow the generation of very high lift and high lift/drag ratio compared to wings and blades commonly used in other fields such as aeronautics and turbomachinery. The project aims to understand the underlying mechanisms of these flow features in order to further enhance the performance of sails and, importantly, to allow the cross-fertilisation of ideas in research fields where there is a need for fluid dynamic efficiency.

The flow field around sails has several uncommon characteristics. The sharp leading edge leads to laminar separation, followed by a laminar-to-turbulent transition and then turbulent reattachment, forming a leading edge vortex (LEV). LEVs are known on flat plates with a sharp leading edge and on delta wings, while on rounded-nose foils used for low-pressure turbines, a similar feature known as the laminar separation bubble (LSB) occurs.

In the present project, it is proposed to test large-scale flexible sails in a wind tunnel to measure forces and the flying shape of sails and then to build a rigid small-scale model to be tested in a water tunnel to perform flow measurements with particle image velocimetry. Experimental measurements will be complemented with computational fluid dynamics simulations to test a wide range of conditions, which are tested with difficulty experimentally. 

There is no closing date for this position, which will remain open until filled.