CONTRIBUTION OF PECULIAR SHEAR MOTIONS TO LARGE-SCALE STRUCTURE

Self-gravitating shear flow instability simulations in a cold dark mat ter-dominated expanding Einstein-de Sitter universe have been performe d. When the shear flow speed exceeds a certain threshold, self-gravita ting Kelvin-Helmholtz instability occurs, forming density voids and ex cesses along the shear flow layer which serve as seeds for large-scale structure formation. A possible mechanism for generating shear peculi ar motions are velocity fluctuations induced by the density perturbati ons of the postinflation era. In this scenario, short scales grow earl ier than large scales. A model of this kind may contribute to the cell ular structure of the luminous mass distribution in the universe.