A METHOD OF ANALYSIS FOR TURBULENT FLOWS USING THE STREAMLINE COORDINATE SYSTEM

A procedure is described for analysing the transport equations for Rey nolds stresses written in a streamline coordinate system, starting fro m the fields of first- and second-order moments of wind velocity measu red in a terrain-following system over topography. In the analysis, th e equations are split into two parts: the first contains the terms tha t can be calculated directly from measurements; the second contains th ird-order moments that are parameterized using suitable models. To eva luate the error associated with both parts, a Monte-Carlo technique th at takes into account the experimental errors is proposed. An example of the application of this method for the Reynolds shear stress equati on, using wind-tunnel data for non-separating flow over a two-dimensio nal valley, is reported. The comparison between the measured and model led parts is fair near the surface, while at higher levels, the modell ed part can be shown to miss a correct treatment of the third-order mo ments. In the frame of this analysis, the use of the correct derivativ e transformation has been found to be significant even for moderately sloping topography.