The Experimental Investigation of Turbulent Boundary Layer Separation

In order to in vestigate the turbulent boundary layer separation, the flow field which was similar to that of Spangenberg-flow maintained in a nearly separating condition was made. Effects due to adverse pressure gradient were investigated by measuring the boundary layer characteristics. Especially measurements of the spanwise velocity distribution were made to examine how the flow field varied in the spanwise direction under the strong adverse pressure gradient accompanied with the separation. From the results of experiments, it was found that the boundary layer characteristics were different from those in the turbulent boundary layer with zero pressure gradient, for example, dp/dy≠0 and wall law was not valid in the region near the separation point, and that the spatial variations of turbulent boundary layer were caused by the strong adverse pressure gradient and the irregular three-dimensional flow fields were obtained.