A Numerical Computation of Air Flow over a Sudden Change of Surface Roughness

摘要: Abstract This paper deals with a numerical study of the influence changes in surface roughness on turbulent boundary layer lower atmosphere under neutral conditions. The whole set equations governing flow is solved by finite-difference method. energy equation included to provide better understanding mechanisms. pressure gradient treated implicitly. Computational results agree well Bradley's observations. A local minimum stress found at short distance from edge (dividing line) case smooth-to-rough transition. Two layers, velocity and layer, are found. height about one-half that layer. Both layers follow 4/5 power law. height-to-fetch ratio for internal be 1/10 1/20 velocity. new nearly equilibrium 1/100 sm...