MEAN FLOW AND SEDIMENT TRANSPORT ON SEDIMENT LAYER IN A HORIZONTAL PIPE

摘要

Mean flow structures in pipe with sediment deposition were calculated by means of an algebraic stress model (ASM) and they are examined with respect to cross-sectional distributions of streamwise mean velocity, Reynolds stress and energy gradient. The calculated results were used for estimation of sediment discharge, bed shear stress and hydraulic energy gradient which is compared with experimental results and also compared with methods using hydraulic radius division. The energy gradient calculated by ASM shows good agreement with experimental and hydraulic radius division in conditions where relative roughness is 2 times mean sand diameter (k_s=2d_m) on the surface of the sediment deposition. Also, the bed shear stress and sediment discharge calculated by the ASM results, are discussed as a function of energy gradient.