Lift forces on axial symmetry particles rotating in a linear shear flow of a rarefied gas

Abstract

We theoretically investigate the lift forces (including shear lift and rotational lift) experienced by nonspherical convex particles rotating in a linear shear flow of a rarefied gas, based on the gas kinetic theory. In our model, the interactions between the gas molecules and the particle surface are assumed to be the Maxwell combined specular-diffuse scattering. By integrating the general expressions for several simple axisymmetric bodies, including spheres, cylinders, disks, and spheroids, the specific expressions for the lift forces acting on these bodies are obtained. The pitching effect of the nonspherical particles results in a transverse force for the shear lift, but there is no transverse force for the rotational lift. The expressions for the orientation-averaged shear lift forces are obtained under a uniform distribution of the particle orientation.