A PHENOMENOLOGICAL THEORY OF QUASI-PARALLEL TURBULENT SHEAR FLOWS.
Interim technical rept.,
JOHNS HOPKINS UNIV BALTIMORE MD DEPT OF MECHANICS
Pagination or Media Count:
Mean velocity and mean shear stress distributions of two-dimensional quasi-parallel turbulent shear flows are calculated using the assumption that the effective turbulent viscosity obeys a rate equation. The effects of generation, convection, diffusion and decay are each represented by the appropriate terms in that rate equation. Thus, together with the equation of motion, they form a closed system for the two dependent variables the effective viscosity and the mean velocity. For a newly homogeneous domain, Prandtls mixing length theory can be shown to be a limiting case. Solutions were obtained for the case of the turbulent non-turbulent interface at the outer edge of the boundary layer. Finally, similarity solutions for the incompressible turbulent boundary layers with zero pressure gradient were calculated, assuming the linear growth of the turbulent boundary layer thickness with an additional simple assumption concerning the approximation of the convection terms. The resulting system of non-linear ordinary differential equations were integrated by the use of an analogue computer. The calculated distributions of the mean velocity, total shear stress and turbulent viscosity were compared with experiments. Author
- Fluid Mechanics