Evaluation of Wind Shear Coefficients, Surface Roughness and Energy Yields over Inland Locations in Namibia

Wind shear coefficients and roughness lengths over inland locations in southern Namibia were evaluated. Ten-minute average wind data collected at Korabib and Warmbad over a one year period were utilized. Mean values of wind shear coefficients are 0.197 and 0.132 and the roughness lengths are 0.187 and 0.017 m at Korabib and Warmbad respectively. Extrapolated hub height speeds and energy yield were found to depend on the wind shear coefficients. Both parameters recorded maximum and minimum values during winter and summer months, and maximum and minimum values during night stable hours and daylight hours respectively. Significant influence of local topographical features on WSCs variation with direction was evident.