Study On Numerical Simulation Of Seepage Characteristics Of Permeable Submerged Dam

The numerical simulation of permeable submerged dam is studied in this paper.Because it is not Darcy seepage that is inside the permeable submerged dam,but non-Darcy seepage.It is necessary to simulate the velocity,pressure and saturation line in order to study the seepage situation inside permeable submerged dam.The CFD FLUENT is used to simulate the permeable submerged dam in which the velocity nephogram,pressure nephogram,the saturation line in non-overflow state,the internal pressure and velocity changes,as well as the water level and velocity changes in the upstream and downstream can be obtained,which provides a reference for the design of permeable submerged dam.CFD FLUENT is used to simulate the permeable submerged dam in this paper,and by using VOF method to simulate the saturation line,the following conclusions are obtained:(1)As for the saturation line,the water level difference decreases with the decrease of the aperture.The shape of the saturation line curve is basically the same,but with the increase of the average aperture,the rate of descent of the infiltration line decreases.(2)In terms of flow velocity,when the water flows into the permeable subsurface dam,the effective velocity of water resistance is almost zero.The outflow velocity from the permeable subsurface dam increases gradually,but decreases gradually with the increase of pore diameter.The velocity trend in the interior of the submerged dam is roughly consistent with the different height from the bottom..In the longitudinal,the closer the velocity gradient is to the outlet of the permeable submerged dam,the larger the velocity gradient is.In the transversen,the velocity is basically same on the same vertical plane,while the closer it reached the exit of rockfill dam,the faster it gets.In practical engineering,a more suitable diameter of permeable submerged dam can be selected by the required downstream flow velocity.(3)In terms of pressure,the initial pressure is 120 Pa when the aperture is 7.13 mm,and the initial height of pressure at the entrance of the permeable submerged dam decreases with the increase of the aperture.The larger the aperture of permeable submerged dam,the greater the impact on internal pressure.Under the same aperture,the pressure decreases with the increase of height,but with the increase of aperture,the pressure decreases with the increase of height;In the longitudinal,the speed of pressure gradient increasing along the flow direction increases with the decrease of water level.In the same water level,the pressure gradient increases along the flow direction.The rock-fill submerged dam can be built by choosing different materials at different positions and pressures.(4)When the flow submerges the permeable submerged dam,the internal seepage isdivided into the seepage at entrance and the seepage at upper surface.Because of the high velocity above,the internal seepage is affected by 10% of the height of the submerged dam,which has a greater impact on its velocity and a smaller impact on its pressure.Therefore,in practical engineering,it is necessary to reinforce the submerged dam with a height of about10% above the submerged dam in order to prevent the damage caused by overflow.