The Decay of Highly Skewed Flows in Ducts

Abstract

The development of a very nonuniform or skewed velocity profile in passing through a diffuser has been examined from the point of view of velocity components induced by line vortices. Account is taken of the effect of dissipation and straining on the strengths of the vortices and the intensities of the induced velocities. Changes with the integrated momentum of the perturbation velocities contribute to the local pressure in the duct, or diffuser, along with friction forces and area changes. An expression is derived for the pressure coefficient of a highly skewed profile flowing through a duct of arbitrary section. The results of experiments with an ejector apparatus are presented and found to support the analytical conclusions. In contrast with slightly skewed flows, diffusion will not inhibit the decay of highly skewed profiles.