Channels, Fall 2020

Channels • 2 020 • Volume 5 • Number 1 Page 11 presence of vortices, which then leads to the “bearing” effect around the surface as discussed previously. Figs 14 and 15 show an increase in the magnitude of reversed flow in the grooves as air moves downstream. It was not until after the separation point of the smooth cylinder that reversed flow appeared in the boundary layer as seen in Fig. 16. This contrasts the vortices found in the grooves of Model A before the separation point and appears to be directly related to the reduction of drag found in Table V. Fig. 13 Velocity distribution in boundary layer (X = -0.0243m) Fig. 14 Velocity distribution in boundary layer (X = -0.01741m) Fig. 15 Velocity distribution in boundary layer (X = -0.00368m)