Force contributions in the equilibrium state according to Eq. (17) for the non-gravitating, rigid sphere in air, given as a function of the Mach number. denotes the pressure force measured at the surface of the sphere, the pressure force measured at the outer boundary of the computational domain, and the momentum transport through the outer boundary. The sum of these three forces is denoted by F_tot. The curve describes a parabola with F ∝ ℳ².