Flow of the Entrance Region in a Porous Pipe : 2nd Report, Uniform Inlet Velocity Profile

The entrance region for laminar flow in porous pipes with small injection or suction is theoretically analyzed. In this paper, a modified momentum integral method in the first report is applied to the entrance flow with a uniform inlet profile, and the following conclusions are obtained. (1) The velocity and pressure distributions, and the wall frictions in porous pipes are obtained by this modified method, and the results are in good agreement with those of Hornbeck's numerical analysis. (2) When the suction velocity is large, the pressure rises and the wall friction is small in the downstream region. (3) The larger the injection velocity is, the shorter the entrance region in porous pipes is. (4) When this method is applied to the entrance flow in rigid pipes, the results are also in very good agreement with the results obtained by Nikuradse et al.