Mean Velocity and Turbulence Measurements of Flow Around a 6:1 Prolate Spheroid

摘要

Investigations of three-dimensional flow around a 6:1 prolate spheroid model wereconducted in the separation and near wake regions along the leeward side. Mean velocity flow field measurements, at alpha = 10 C and 15 deg and at Re=1,300,000 were obtained at four axial locations along the afterbody. Boundary layer profiles and Reynolds shear stress measurements were obtained at two axial location, with alpha = 10 deg and Re=4,000,000. Results indicate vortical flow along the surface of the body, growing a strength with increasing Reynolds number and increasing angle of attack. Skewing of the three-dimensional boundary layer is seen in the profiles, with surface shear stress direction lagging the local free-stream velocity direction. Turbulence measurements show that distribution of Reynolds stress quantities is different than two-dimensional flow over a flat plate. Estimates show that eddy viscosity is not isotropic. The flow model predicts high values for the mixing length. Keywords: Aerodynamics; Turbulent flow; Boundary layer transition; Turbulent boundary layer; Flow separation; Wind tunnel models; Test evaluation; Aerodynamic drag; Flow rate/velocity. (mm)