Study On Improving Measures For Supercritical Flow Bend

In actual hydraulic project arrangement, because of restrict condition of topographic, project structure and the whole collocation of hinge, the rushing current bend channel usually are hardly avoided. The water current will do curve movement after getting into the bend channel, under the together function of centrifugal inertial force and gravity, and the fluid state becomes exceptionally complex. These mainly behave at that the water flow losses it's instability and generates the transverse gradient that the water surface of concave bank is higher than convex bank, and that the big diamond impact wave even occurs on the water surface. All of these existing terrible flow conditions lead to that it needs increase peripheral wall height, and add the whole project amount and that after operating, in bends channel it represent that unit discharge, longitudinal current velocity , water depth are non-uniform in transverse distribution, even occur sediment deposition. Therefore the improvement of supercritical flow bend is the concrete problem which needs to be resolved in the actual projects.On the basic of understanding the essential principle of bend flow, according to the hydraulic model experiment of the emptying tunnel in Ma Jiayan reservoir, this paper proposed two kinds of project measures, one is to install diversion bank on the bended channel base, the other is to set guide wing on the side of wall. And then the experiment has been carried out to analyze and compare the effects. For reducing the curve water surface horizontal gradient and improving the fluid state, the both measures have good effect. Especially they improved the thickness of curved way water tongue and the uniformity of current velocity which distribute in a cross section, promise the stability and the safety of the end jet flow.With further studying on supercritical flow bend, according to the usual conducting thoughts in river improvement, this paper gives a new method which are named 'inverse extra-high on bended channel base'. And according to this method, we can take measures that raise the board height of convex bank and debase concave bank's, then shaping a horizontal gradient bended channel board. Based on the principle of volume constancy and the reflection theory of rapid flow shock wave, it gives the hydraulic design method...