NUMERICAL-SIMULATION OF 3-DIMENSIONAL SELF-GRAVITATING FLOW

The three-dimensional flow of a self-gravitating fluid is numerically simulated using a Fourier pseudospectral method with a logarithmic var iable formulation. Two cases with zero total angular momentum are stud ied in detail, a 32(3) simulation (Run A) and a 64(3) simulation (Run B). Other than the grid size, the primary differences between the two cases are that Run A modelled atomic hydrogen and had considerably mor e compressible motion initially than Run B, which modelled molecular h ydrogen. ('Compressible motion' is that part of the velocity which has zero curl, but non-zero divergence.) The numerical results indicate t hat gravitational collapse can proceed in a variety of ways. In Run A, collapse led to an elongated tube-like structure, while in Run B, col lapse led to a flatter, disk-like structure.