Research On Hydraulic Characteristics Of Flood Discharge Strucures Of Sanhekou Water Conservancy Hub

In recent years,a serious of high dam projects with high water head,high discharged volume and high discharging power have been build at high mountain valley region in south west of China.There out,a series of problems are exposed,for example,Geologic landslide on two shores caused by store water on the upstream of hub,slope stability problems on downstream river slope caused by the serious atomization on the downstream of the tub,and severe local erosion and alongshore erosion of river channel.Therefore,it have very important research significance that arrange structures of flood discharge energy dissipation reasonable according to the engineering characteristics is one of a key technology to ensure the safety of hydraulic structure and make the hub perform the expected benefitsThe centre building of regulation and storage in Hanjiang-to-Weihe River Water Transfers Project--Sanhekou Water conservancy hub is studied in this paper.The shape of outlet works determined in original scheme are modified through physical modeling experiment;The RNG k-? turbulent model and VOF method are used to do 3-D numerical simulation about the hydraulic characteristics of the slit-type bucket in the bottom holes and the fluctuating pressure,which given by the aerial drainage from the surface and bottom holes,suffered by bottom plate of the water cushion.The results are as follow:(1)The discharge capacity of surface and bottom hole in original scheme can meet design requirement;water tongue flow from bottom holes disperse longitudinal well;water tongue of middle hole has farthest droppoint,which diffuse unilaminarly and horizontally;the throw distance of water tongue of left and right surface holes are a little short,which are deviled into upper and lower two layers to disperse.There are three questions existed in original scheme: the distance between two droppoints of water tongues flow from two bottom holes is relatively close,not totally separate;water tongues flow from the left and middle surface holes often hit the side slope of the water cushion;when reservoir reaches calibration water level,partial water cushion plate suffered surge pressure is more that required 15×9.8k Pa;on the moment of opening and closing of the gate,the right side of the edge of discharge tooth dikes of the left surface holes sometimes have water fall to hit the lock room of the bottom hole.(2)The proposed scheme solves the problem of the original scheme,but fluctuating pressure intensity of partial back plate is relatively big cause the droppoints of left and right surface hole have cross.The suggestion that increase the depth of the water cushion downstream to reduce the fluctuation pressure strength of the bottom plate of the water cushion and relevant solution are put forward in this paper.(3)Simulated results about the length of vertically into the water,highest elevation of slit-type bucket and hole figure pressure value are measured fit well with physical modeling experiment.(4)Simulated results about the intensity of fluctuating pressure,probability density distribution and power spectral density are fit well with the results come from physical modeling experiment.It is available that use numerical simulation to study pulsating pressure at the bottom plate of the water cushion.