Physical Model Experimental Study on Flow and Sediment in Warping Area in the Middle Yellow River

摘要

According to the water and sediment condition designed, a physical scale model was built to simulate the warping process which arrived at some important conclusions, some of which are given as follows: (1) In the initial warping stage, sediment loaded flow begins to scatter all over the warping area, sediment tends to fall just near the inlet, flow surface becomes steeper, the flow velocity sees bigger extremes, due to the influence of the initial topography , sediment concentration decreases rapidly, the suspended sediment tends to become fine. (2) In the middle and final stages, with the deposition extending downstream and the bed at the return flow gate rising, a mainstream gully is gradually formed in the warping area, the area undergoes accretion mainly due to overflowing over floodplains. The flow surface becomes mildly sloped, and the flow in the mainstream gully goes faster, along the cofferdam and longitudinal dike in most cases. The sediment concentration decreases downstream without obvious changes in the particle sizes. The experimental result has provided a sound technical support for the design and the operation of the prototype warping project.