Nonlinear shallow fluid flow over an isolated ridge

The shallow water theory is applied to the study of one dimensional fluid flows over an isolated ridge. The work was motivated by the desire to investigate the phenomenon called the chinook which occurs on the eastern side of the Rockies and is characterized by extremely strong winds which blow from the mountains. The motion that arises from an initially uniform flow involves the formation of hydraulic jumps both on the windward and leeward sides of a ridge. Special emphasis is put on determining analytically the asymptotic structure of such flows with jumps by solving the appropriate "steady" state equations. The presence of the hydraulic jumps and a rarefaction wave was revealed by preliminary numerical solutions of the time dependent problems. These numerical results demonstrate the evolution in time of the various features of the flow found in the asymptotic solutions.