Department of Aerospace and Ocean Engineering
Structure of Vortical Separations
Perspective topview of an
oil-flow on the bump
Abstract
Surface mean pressures, oil flow visualizations, and 3-velocity-component laser-Doppler velocimeter measurements are presented for a turbulent boundary layer of thickness d over 2 axisymmetric bumps of height H = d, 2d and one symmetric bump of H = 2d. LDV data were obtained at one plane x/H > 3.26 for each case. Complex vortical separations occur on the leeside and merge into large stream-wise mean vortices downstream for the 2 axisymmetric cases. The near-wall flow (y+ < 90) is dominated by the wall. For the axisymmetric cases, the vortices in the outer region produce large turbulence levels near the centerline and appear to have low frequency motions that contribute to turbulent diffusion. For the case with a narrower spanwise shape, there are sharper separation lines and lower turbulence intensities in the vortical downstream flow.
Publication
Gwibo Byun, Roger L. Simpson and C.H. Long, “A STUDY OF VORTICAL SEPARATION FROM THREE-DIMENSIONAL SYMMETRIC BUMPS”, AIAA-2003-0641, 41st Aerospace Science Meeting and Exhibit, Reno, NV. (Accepted to AIAA Journal)
Roger L. Simpson, C.H. Long and G. Byun, “STUDY OF VORTICAL SEPARATION FROM AN AXISYMMETRY HILL”, International Journal of Heat and Fluid Flow, Volume 23, Issue 5, October 2002, Pages 582-591
Data available for download
§ Pressure data
Pressure
coefficient (CP) : Large
Bump3_Cp.dat (36KB), Small Bump3_Cp.dat(36KB),
Bump1_Cp.dat(2KB)