Flow around Three-Dimensional Rectangular Cavity.

In this paper we describe the flow associated with three-dimensional surface-mounted rectangular cavities. The experiment was carried out in two types wind tunnel and water channel. A significant aspect of the study has been an examination of the effects of changing the flow incidence angle from 0 degree to the normal from the cavity major axis to 90 degrees. The cavities investigated have had sectional geometries with width/depth of 1.0 and planform aspect ratio of length/width equal to 9.5. The time mean surface pressure distributions, mean velocity inside cavities, and mean velocity and turbulent intensity in the immediate wake of the cut-out were measured as the flow incidence angle was varied. The flow pattern inside cavities was observed by flow-visualization. Consequently it was found that (i) the greatest disturbance to the cavity flow occurs when the flow incidence angle is approximately 75 degrees to the longest cavity axis, and (ii) this is reflected in a large asymmetric wake associated with an increase in cavity drag.