1997 Volume 1997 Issue 73 Pages 3-14
The turbulence flow over a circular hill, having a cosine-squared cross-section and a maximum slope of about 32°, was investigated using split-fiber probes designed for measuring flows with a high turbulence and separation. Profiles of the means and variances for the three velocity components are presented and compared with those in the undisturbed (no- hill) boundary layer. The turbulent boundary layer separated behind the crest and reattached just at the lee foot of hill. The pronounced speed- up of flow occurs not only at the hilltop but also at the midway slope on its side. The maximum perturbations in the longitudinal and vertical velocity variances were observed at the height of hill (z/h=1), corresponding to the separated recirculating flow on the lee slope of the hill, while the maximum in the lateral velocity variance appeared at the height of z/h=0.125 beyond the hill, corresponding to the low-frequency motion in the wall layer.