Calculations of Free Turbulent Shear Flow with a Three Equation Turbulence Model by J. C. Rotta

摘要

Calculations were made using a system of partial differential equations which describe plane and axisymmetric turbulent flows at high Reynolds numbers. This system includes three equations to describe turbulent field quantities in addition to the two equations for the longitudinal and cross flow component of the mean flow. These are the equation for the kinetic energy of fluctuations, the equation for a characteristic length scale, and the transport equation for the Reynolds shear stress. After the necessary closure assumptions, which contain only empirically determinable coefficients, the equations form Rotta's turbulent model. The equations were numerically solved for three cases of free shear flow and the influence of the coefficients of the shear stress transport equation on the solution was studied. A single set of coefficients is given, for which the calculated flow cases are found in satisfactory agreement with experimental results.