Abstract：The backward-facing step flow is a classic research topic of separation flow. To investigate the flow structure of backward-facing step and discuss the step flow hydraulic characteristics, three-dimensional k-ε turbulence model was built by FLUENT software to simulate the backward-facing step flow in wide Reynolds number range from 50 to 50 000. Comparing the simulation results with PIV test results, the recirculation zone features and the recirculation zone length changes were analyzed. The results show that analog value agrees well with test value with stable recirculation zone. The consistent trend of recirculation zone length illuminates that the model results are reliable. The hydraulic features of backward-facing step flow are affected greatly by recirculation zone, particularly in the separation point of minimum pressure with vorticity diffusion along the edge of recirculation zone. The velocity is minimum in the recirculation center zone with great turbulent energy.
2014, Vol. 35 
