Calculation methods

The stress-increment, entity, kinetic, Brownian motion, and classical theories for turbulent shear flow are reviewed and the basic principles for calculating this type flow are examined. The use of differential equations, instead of algebraic formulas, for the Reynolds stresses gives or promises greater accuracy in predicting shear stress in boundary layers or other thin shear layers, and are the first to be suitable for complex turbulent flows such as interacting shear layers and shear layers that are perturbed by deflection or acceleration in addition to mean shear. Numerical experiments in determining the effects of small and large secondary strain rates on turbulent shear layers, and streamline curvature in the plane of the mean shear stress are reported.