Direct simulation Monte Carlo analysis of subsonic flow over a rotating circular cylinder in rarefied conditions

Abstract

When a rotating circular cylinder is subjected to a uniform flow, a transverse force is generated which is known as the Magnus lift force. The present study investigates the flow past a rotating circular cylinder under highly rarefied conditions, ranging from the mid-transition to the free molecular regime. The flow condition in the present study was subsonic and the cylinder tangential velocity was kept a fixed fraction of that in the freestream. The variation in flow rarefaction was achieved by varying the Knudsen number, Kn. The coefficients of pressure, skin friction and heat transfer along with the aerodynamic coefficients such as lift and drag have been investigated as a function of the Knudsen number. The present study uses the monatomic gas Argon (Ar) as the flowing fluid. For the numerical solution, the stochastic molecular approach known as the direct simulation Monte Carlo (DSMC) method was employed. Results showed that both the lift and drag coefficients increase with flow rarefaction, and there was a subtle interplay between the pressure and viscous components of these coefficients.