Fluid Dynamics

, Volume 44, Issue 1, pp 141–157

Aerodynamic coefficients of a spinning sphere in a rarefied-gas flow

  • Authors
  • A. N. Volkov
Article

DOI: 10.1134/S0015462809010153

Cite this article as:
Volkov, A.N. Fluid Dyn (2009) 44: 141. doi:10.1134/S0015462809010153

Abstract

A three-dimensional rarefied-gas flow past a spinning sphere in the transitional and near-continuum flow regimes is studied numerically. The rarefaction and compressibility effects on the lateral (Magnus) force and the aerodynamic torque exerted on the sphere are investigated for the first time. The coefficients of the drag force, the Magnus force, and the aerodynamic torque are found for Mach numbers ranging from 0.1 to 2 and Knudsen numbers ranging from 0.05 to 20. In the transitional regime, at a certain Knudsen number depending on the Mach number the Magnus force direction changes. This change is attributable to the increase in the role of normal stresses and the decrease in the contribution of the shear stresses to the Magnus force with decrease in the Knudsen number. A semi-empirical formula for the calculation of the Magnus force coefficient in the transitional flow regime is proposed.

Keywords

spinning spheretransitional flow regimedrag force coefficientMagnus forceaerodynamic torque coefficient

Copyright information

© Pleiades Publishing, Ltd. 2009