Statistical Charactaristics of a Turbulent Boundary Layer over a d-type Rough Surface

Measurments have been made to study the statistical charactaristics of a turbulent boundary layer over a d-type rough surface at a momentum thickness Reynolds number of R_θ≒5000 at which the skin friction coefficient took a constant value. Results showed that both the skewness and flatness factors of the three components of the fluctuating velocity for the outer layer in the present rough boundary layer were significantly different from those of smooth surface turbulent boundary layer. The spectra of u, v, w and uv show the inertial subrange relation (&acd