Abstract
Part I of this study presented experimental measurements of the primary and secondary boundary-layers over a flat plate with coupons containing obliquely aligned control elements. The flow control elements used in the study were right-angle, truncated cones of elliptical cross-section. The boundary-layer measurements were performed for test coupons with arrays of elements aligned at 0°, -5°, -10°, and -15° to the free stream flow direction under free stream velocities of 2, 5, and 10 m/s. The resulting turbulent boundary-layer measurements demonstrated the ability of obliquely aligned elements to produce tailored secondary flows. Since the test coupons used were of a finite span, the results also demonstrated that tailored longitudinal vortical structures can also be generated using the arrays. In Part II, CFD simulations are presented that were performed using ANSYS FLUENT 12.0 with grids resolving the flow control element features. For each of the simulations, the realizable k-e turbulence model was used, and solutions were allowed to converge to residuals near 1×10 -5 for flow and turbulence quantities. Grid independence was evaluated by comparing the flow angles predicted at the downstream measurement plane. The simulation results compare well with experimental measurements of spanwise flow, yet because of a lack of grid resolution at the leading edge of the plate, the simulation results do not agree with experimental measurements in the streamwise flow. The difference in the levels of agreement for the velocity components implies that the production of the transverse flows using oblique element distributions is an artifact of inviscid-flow or pressure-based effects.
Published Version
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