EXTENSION OF THE MIXING LENGTH THEORY TO A POROUS TUBE FLOW WITH INJECTION OR SUCTION

[摘要] References(14)Cited-By(1)Effects of mass injection or suction on mixing length was investigated for the case where a hydrodynamically fully developed impermeable tube flow entered a porous tube. Mixing length near the wall is increased by injection and decreased by suction, being well correlated with a dimensionless distance y++ based on the local friction velocity. The mixing length in the core region is decreased by injection and increased by suction. The mixing length theory was extended so as to express the upstream effect on momentum exchange by introducing a memory function with a parameter of longitudinal traveling distance LMX of fluid lump. The relation LMX=8R was obtained by applying the extended theory to the mixing length variation in the core region.