MODERN HIGH-RESOLUTION SHOCK-CAPTURING METHODS FOR STRUCTURE EVOLUTION IN COSMOLOGY

Cosmological one-dimensional structures with pressure are considered. Their nonlinear evolution is studied. The partial differential equatio ns for this evolution are numerically solved. The code is based on a m odern high-resolution shock-capturing algorithm. The main goal of this paper is to prove that this algorithm can be applied in Cosmology. Ba ryon matter is considered as an ideal gas. In pressureless cases, our code is severely tested by comparing numerical results with Zel'dovich 's solution. Pressure effects are discussed; in the case of a pure bar yon fluid, the shell crossing phenomenon predicted by Zel'dovich's sol ution is either retarded or prevented by pressure. In the case of a mi xing of baryons and collisionless particles, the total gravitational f ield plus pressure produce shocks. Possible extensions and improvement s of the code are discussed.