Flow Uniformalizing Effect of Damping Screen in Pipe Flow : The Case of S-Shape Velocity Distribution

Abstract

As part of a serial study of the effect of a damping screen on the velocity distribution of pipe flow, the case of a flow with S-shape velocity distribution is analysed theoretically. The analyses are performed for the case of a single isotropic damping screen and for three other combinations of (1) an isotropic damping screen and an isotropic lattice, (2) the screen and an anular lattice and (3) the screen and a radial lattice. Theoretical results show that, for a single isotropic screen, the final damping ratio is the same as in the case of an axi-symmetric axial velocity distribution, but the flow uniformalizing process is more gradual than the axi-symmetric case. It is also made clear, for cases of combined damping devices, that the damping process vanishes downstream of an isotropic lattice, and a secondary flow is generated downstream of an annular or radial lattice.