Similarity solutions for density currents
Mitchell, James Presley
Plapp, John E.
Master of Science
In this thesis, a steady-state hydrodynamic analysis of density currents, or flows of silt-laden sea water adjacent to the bottom of the ocean, is presented. The density current is considered to be analogous to the turbulent free-convection boundary layer encountered in heat transfer. A similarity solution in which the maximum velocity, the depth of flow and the sediment content at the bottom are taken to be proportional to a power of the distance measured along the bottom, is used to solve the integrated form of the momentum equation and a sediment transport equation which is derived in the thesis. The resulting equations from the hydrodynamic analysis are applied to the density current considered to have occurred after the 1929 earthquake in the Grand Banks region off Newfoundland. Values of the sediment content, depth of flow, and predicted velocities corresponding to the observed velocities for this current are obtained. The author has concluded that since the results obtained for the Grand Banks earthquake seem reasonable, the treatment of density currents as turbulent boundary layer flows is justified.