A procedure for determining the importance of basic events to systems undergoing phased missions

The region of separation in a turbulent boundary layer flow is considered. The complexity of the flow and its corresponding equations is noted. A model, valid for a slowly separating region, with constant mean velocities and relatively small fluctuation intensities is developed. This model is expressed as a set of four linear partial differential equations.

An approximation for the Reynolds stress tensor is derived. It is found by first solving for the fluctuating velocities and then forming the appropriate correlations. . This is accomplished by uncoupling the four governing equations via the vorticity components. The fluctuating velocities are then determined from the vorticity components.

Approximations to the fluctuating velocities are made and then correlations are constructed to form the Reynolds stresses. It is found that the Reynolds stresses can be represented by a polynomial in y. Recent experimental work may be used to define the coefficients of the polynomial approximations and thus allow Reynolds stress evaluations throughout the separated region.