425 Turbulent Structure near the Wall for the Precise Equilibrium Boundary Layer Developing over Rough Surface
Details
Measurements have been performed in the vicinity of the roughness element for the equilibrium boundary layer developing over the rough wall, proposed by J.C. Rotta. Pressure and velocity distributions were measured in the range of the a roughness pitch length between roughness elements at x≒2180 and 2800mm. Pressure drag coefficient is almost constant to roughness Reynolds number k^+. Mean velocity profiles have an inflectional point at y_T/k≒0 and reverse flow exists for y_T/k<0. Then, in the cavity larger eddy having a scale of cavity width was confirmed from the flow pattern described with mean streamline. The frequency f of the reverse flow is proportional to u_τ/b.
