Protostellar Hydrodynamics: Constructing and Testing a Spatially and Temporally Second-Order--accurate Method. I. Spherical Coordinates

摘要: In Boss & Myhill (1992) we described the derivation and testing of a spherical coordinate-based scheme for solving hydrodynamic equations governing gravitational collapse nonisothermal, nonmagnetic, inviscid, radiative, three-dimensional protostellar clouds. Here discuss Cartesian based on same set equations. As with coorrdinate-based code, employs explicit Eulerian methods which are both spatially temporally second-order accurate. We begin by describing in coordinates numerical used this particular code. Following Finn Hawley (1989), pay special attention to proper implementations high-order accuracy, finite difference methods. evaluate ability handle shock propagation problems, through convergence testing, show that code is indeed To compare discussed here (1992), two codes calculate standard isothermal test case Bodenheimer (1981). find improved codes, intermediate bar-configuration found previously disappears, cloud fragments directly into binary system. Finally, present results from new nonisothermal collapse.