On the numerical computation of laminar and turbulent boundary layers at gas-liquid interface

A finite difference scheme is developed for solving laminar and turbulent boundary layer problems which simulate two dimensional, steady state flows coupled across a density interface. The scheme is an extension of the differential mean flow procedure. Turbulent mixing in rough wall flows is discussed and a diffusion layer model is extended to include effects of roughness on momentum transport in boundary layers. Calculations of flows adjacent to rough, solid walls and an air water interface roughened by wind waves are compared to available data. Parameterization of the effective roughness of surface wave spectra is examined. Wave breaking and wave turbulent interactions are considered, and a simple length scale model is provided to simulate the augmented mixing observed in flows beneath laboratory wind waves. The computation of gas liquid flows by additional methods is discussed. An algorithm for obtaining self similar solutions to laminar boundary layer problems by Runge-Kutta integration is provided. The applicability of integral techniques to coupled flows is investigated and an analytic similarity solution for laminar problems with a plane, phase changing interfacial boundary is presented.