Investigation of the law-of-the-wall for a turbulent boundary layer flow at adverse pressure gradient at Reθ up to 10000 using large-scale PIV

Kurzfassung

We present an experimental investigation and data analysis of a turbulent boundary layer flow at a significant adverse pressure gradient at Reynolds number Reθ = 10000 using large field PIV. The aim is to find a wall-law for the mean-velocity in the inner layer. We consider scaling law diagnostic functions together with the Millikan argument. The inner part can be fitted by the log-law, but is progressively reduced. In the outer part, the overlap layer, the loglaw ceases to be valid. Instead, a modified log-law gives a good fit, which needs as parameters the pressure gradient parameter and the mean inertial effects. We then attempt to find a quantitative description which is local in wall-normal direction without streamwise history effects.