Slightly rarefied gas flow over a specularly reflecting body

The asymptotic behavior (for small Knudsen number) of the steady flow of a rarefied gas over a specularly reflecting body with arbitrary but smooth shape is investigated on the basis of the linearized Boltzmann–Krook–Welander equation. As applications of the theory, a sphere in a uniform flow of gas and that in a gas at rest with a uniform temperature gradient are considered. The velocity and temperature fields around the spheres and the drag and thermal forces acting on the sphere are obtained. The formulae of the forces are compared with those given by various approximate methods and those for other types of boundary conditions.