Numerical Simulation On The Backwater Of Piers

At the design of the bridge, the calculation of bridge opening, the arrangement of diversion structures and the general scheme comparison are all based on hydraulic computation. The hydraulic computation of bridge, except for natural stream and unregulated bed, is based on the height of backwater. This is because of the aperture of piers compresses water, so the velocity of water increases and where close the flooding earth bank produce the backwater that is higher than the normal level. And the downriver water surface is lower than the normal level, so between the earth bank there will be coming huge pressure difference, which will cause dangerous at the period of flooding. And the backwater will strongly affect the height of earth bank and the bridge clearance. So the height of backwater has very important significance, and this thesis makes some research at the backwater.The thesis firstly reviews briefly the mechanism of backwater and the effect factors, and then analyses the factors that are relevant with the backwater in the formulae used usually at home and abroad, and makes a summary of domains and conditions of the adoption of the formulae. Because there is not a uniform formula can be accepted at the present time, so it is necessary to analyze the backwater of piers using a numerical method. As the following, the thesis simulates the situation of flow field and backwater at piers with plane 2D numerical module.The thesis utilizes the FLUENT software that is used to calculate liquid equations to establish two dimensional horizontal numerical simulation at piers and chooses a set of laboratory data to demonstrate the reliability and rationality of the simulation .The result indicates that the module can simulate the situation of flow and calculate the backwater at the piers. Consequently, with the change of different factors affecting the height of backwater, the thesis analyses the reasons of the height nearby the piers. The result concludes that the modules can simulate the atmosphere of water flow and backwater at piers well and have certain utilization, and the same time, instruct the design of the bridge in some facets. It is significative to the calculation of the backwater of piers.