Turbulent flow in a rectangular recess in the wall of a plane duct

Turbulent flow of an incompressible fluid in a plane duct with a rectangular recess is investigated for relative recess depths of 1-3 and Reynolds numbers of the incoming flow ranging from 10 to the 4th to 3.5 x 10 to the 5th. Measurements of the mean and fluctuation velocities are presented, and calculations are carried out using a two-parameter turbulence model. A comparison between the predictions of the model and experimental data shows that it is important that the model allow for the effect of the curvature of the lines of flow on the three-dimensional scale of turbulence.