BUOYANCY EFFECTS ON UNSTEADY LAMINAR AND ROTATIONALLY SYMMETRICAL BOUNDARY LAYER

Abstract

Initiai development of the laminar boundary-layer flow over an impulsively started translating and spinning isothermal body of revolution in the case of mixed convection is investigated. Velocity components and temperature are expanded in series in powers of time. Leading and first order functions are obtained analytically and second order functions are determined numerically. The general results are applied to a sphere to investigate the effects of density variations on velocity field and on the onset of separation. The buoyancy force is more effective for small rotational speeds and facilitates the onset of separation for opposing flow and retards it for aiding flow.