Free Surface Axially Symmetric Flows and Radial Hydraulic Jumps

Abstract

Free surface, axially symmetric shallow flow is analyzed in both the centrifugal and centripetal directions. Referring to the inviscid steady flow over a flat plate characterized by a unique value of specific energy, the analytical sub- and supercritical solutions are determined. Furthermore, the sub- and supercritical steady solutions for the flow with friction over a flat plate are determined, provided that inertial terms are important compared with frictional terms. In the inviscid case, the sub- and supercritical solutions over a bottom topography are determined, provided that the bottom unevenness is compatible with a continuous solution. In the fundamental case of inviscid flow over a flat plate, the discontinuous solution also is analyzed for a direct hydraulic jump imposed by proper boundary conditions. In the simple scheme of an inviscid shock of zero length, the jump position and the sequent depths are analytically derived, thus indicating that all results are uniquely functions of one dimensionless number, i. e., the specific energy ratio between the sub- and supercritical flows.