Compressible Flow in Front of an Axisymmetric Blunt Object: Analytic Approximation and Astrophysical Implications

摘要: Compressible flows around blunt objects have diverse applications, but current analytic treatments are inaccurate and limited to narrow parameter regimes. We show that the gas-dynamic flow in front of an axisymmetric body is accurately derived analytically using a low order expansion perpendicular gradients terms parallel velocity. This reproduces both subsonic supersonic measured simulated for sphere, including transonic regime bow shock properties. Some astrophysical implications outlined, particular planets solar wind clumps bubbles intergalactic medium. The standoff distance normalized by obstacle curvature $\sim 2/(3g)$ strong limit, where $g$ compression ratio. For Mach number $M$ approaching unity, thickness $\delta$ initially weak, draped magnetic layer few times larger than incompressible with amplification ({1+1.3M^{2.6}})/({3\delta})$.