Turbulence characteristics in flow over large roughness elements
Abstract
Measurements with a hotfilm anemometer were performed in free surface flow over a bed composed of hemispheres. The meanvelocitytoshearvelocity ratio at a certain distance from the theoretical wall was found to decrease when the flow depth was reduced. Coefficients in the logarithmic law of velocity distribution were determined as functions of relative roughness. Relative turbulence intensity outside separation pockets also decreased with the increase of relative roughness. The probability density function of velocity fluctuations near the bed was found to be skewed and more peaked than is normally the case.
 Publication:

DISA Information
 Pub Date:
 March 1976
 Bibcode:
 1976DISA........26B
 Keywords:

 Flow Velocity;
 Free Flow;
 HotFilm Anemometers;
 Surface Roughness Effects;
 Turbulent Flow;
 Velocity Distribution;
 Boundary Layer Flow;
 Data Reduction;
 Flow Measurement;
 Probability Density Functions;
 Shear Flow;
 Fluid Mechanics and Heat Transfer