Flow past a yawed cylinder of finite length using a fictitious domain method

Abstract

In this work, the flow past a finite-end yawed cylinder is studied. This constitute a first step to understand the motion of freely moving particles. To this aim the Finite Volume / Fictitious Domain (FV/FD) method developed in the PeliGRIFF code (Wachs et al., 2015) is intensively used. This method is validated using numerical results of the literature for a cylinder of finite length whose direction is parallel to the flow (Auguste, 2010). Efforts and vortex shedding frequencies are carefully analysed giving strong confidence in the numerical methodology. A detail study of the flow past a cylinder of aspect ratio L/D = 3 (where D is the diameter and L the length) at moderate Reynolds numbers (Re = rUD/μ = 200) is also carried out. The influence of the yaw angle (ranging from 0◦ to 90◦) is identified both on the wake and on the hydrodynamic efforts. Three different regimes are successively encountered including standing-eddy pattern as unsteady vortex shedding. Otherwise the independence principle which states that the normal force on the cylinder only depends on the normal component of the velocity (Sears, 1948), is compared to the numerical simulations. Results indicate that the independence principle is inaccurate in this flow regime. A linear law obtained in the Stokes regime should be preferred