CORRELATION OF MEAN VELOCITY-MEASUREMENTS DOWNSTREAM OF A SWEPT BACKWARD-FACING STEP

The effect of backward-facing step sweep angle on the mean turbulent velocity field has been measured at subsonic speeds. A single component hot-film anemometer was used in a wind tunnel to measure the velocity normal and parallel to three 1.27-cm-high, backward-facing steps with sweep angles of 0, 15, and 30 deg. A swept step flowfield provides a useful and special test case for modelers of three-dimensional turbulent flows. This is illustrated here by testing the ability of Coles' wall-wake model and the Baldwin-Lomax viscosity model's ability to describe the measured profiles. The Coles profiles are applied to regions of attached flow. The effects of sweep angle on the wake parameter PI downstream of reattachment is strong. The experimental outer-flow velocities were used to evaluate the constants in a modified form of the Baldwin-Lomax model. The resulting constants were in fair to good agreement with the recommended values except downstream of reattachment.