Experimental study on flow field and turbulence characteristics of street inlet

Based on the urban flood experiment platform, the three-dimensional acoustic doppler velocimetry (ADV) was used to measure the distribution of flow velocity and turbulence intensity near the street inlet under the condition of large water depth. The experimental results show that a vortex appears in the center of the street inlet when the inflow depth is large enough. Due to the interaction of inflow and vortex, the velocity in the center of the vortex is greater than that in the edge, the longitudinal velocity of the vortex points to the downstream side is greater than to the upstream side and the maximum velocity of each layer is located near the downstream edge of the street inlet. At the same time, the vortex caused by the street inlet greatly increases the turbulence intensity of flow. In case 2. the depth-averaged turbulent kinetic energy of flow increases form 0.004m2/s2 at the upstream of the flume to 0.145 m2/s2 at the downstream edge of the street inlet. The effect of intense turbulence relatively weakens the influence of bottom friction, thus the vertical distribution of velocity follows the constant and linear law, which does not conform to the logarithmic distribution characteristics of the open channel flow. The above test results can fully reflect the flow field and turbulence characteristics around the street inlet, and provide a reference for the design optimization and numerical simulation. © 2020, Editorial Board of Journal of Huazhong University of Science and Technology. All right reserved.