Dynamical friction for supersonic motion in a homogeneous gaseous medium

摘要: The supersonic motion of gravitating objects through a gaseous medium constitutes classical problem in theoretical astrophysics. Its application covers broad range and scales from planets up to galaxies. Especially the dynamical friction, caused by forming wake behind object, plays an important role for dynamics system. To calculate standard formulae, based on linear theory are often used. It is our goal check general validity these formulae provide suitable expressions friction acting moving basic physical parameters problem. We perform sequences high resolution numerical studies rigid bodies supersonically homogeneous medium, total drag which sum gravitational hydro drag. study cases without gravity with purely hydrodynamical drag, as well objects. From final equilibrium state simulations, we compute direct integration pull embedded object. experiments confirm known scaling laws dependence derived earlier semi-analytical studies. As new result find that shock's stand-off distance revealed minimum spatial interaction scale friction. Below this radius, gas settles into hydrostatic state, causes no net onto body. Finally, derive analytic estimate can be used force.