Investigations of Rough Surface Effects on Friction Factors in Turbulent Pipe Flow

The results of an experimental investigation of the effects of surface roughness on turbulent pipe flow friction factors are presented and compared with predictions from a discrete element roughness model which had been developed previously. Friction factor data were acquired over a pipe Reynolds number range from 10,000 to 600,000 for eleven different rough surfaces, nine of which had uniform roughness elements and two of which were roughened nonuniformly. These surfaces covered a range of roughness element sizes, spacings and shapes. Predictions from the discrete element roughness model were in very good agreement with the data for both the uniform and nonuniform roughness cases.