Assessment of S-76 rotor aerodynamic performance in hover on unstructured mixed meshes

Abstract

In the present study, numerical prediction of the aerodynamic performance of the S-76 rotor in hover was conducted by using an unstructured mixed mesh flow solver. In the present mixed mesh methodology, the near-body flow domain is modeled by using bodyfitted prismatic/tetrahedral cells, while Cartesian mesh cells are filled in the off-body region. To better resolve the flow characteristics in the off-body flow region, high-order accurate weighted essentially non-oscillatory (WENO) scheme is employed. An overset mesh technique is adopted to transfer the flow variables between the two different mesh regions. The calculations were made for three different blade configurations, including swept-taper, rectangular, and swept-taper-anhedral tip shapes, and the results were compared with experimental data. The calculations were also made to investigate the effect of blade tip Mach number. The detailed flow characteristics, such as tip-vortex trajectory, vortex core size, and first-passing tip vortex position depending on the tip shape, were also examined.