The Study On The Tiny Water Wave Digital Image Testing System

The change of tunnel air pressure wave (TAPW) is the very important factor that should be considered when designing tunnel and maxim speed of high-speed train. Then, it is necessary to research the change when high-speed train running in tunnel.Currently, for the problem, it has almost three methods to deal with it. Theory calculation model test and plot test. Because of the complexity of plot, it has more difficult in testing pressure wave in plot, basically, the third method shouldn't be considered. But with good direct observation and operation property, and with high compare and good superiority, model test method is accepted. There are two methods when using model test method. Test in wind hole and test in shallow water groove (SWG). The second method is discussed in the thesis. According to fluid mechanics relative theory, shallow water wave (SWW) has properties similar to TAPW. Then we can use SWG to simulate tunnel, use SWW to simulate TAPW, when dynamic SWW height is measured, and with some proportional calculation, the change of TAPW is test and measuring. In the test system the thesis discussed, SWW is the test object, by gathering change of SWW digital image with CCD and using computer to analyze and process the digital image, the SWW height can be worked out, then the change of TAPW can be also come out with some proportional function calculation.The difficulties to model test are as fellows: Real-Time test of SWW and differential rate of SWW height. They are two key aspects in model test system. For them, some different test projects and theory methods and their merit and weaknesses and feasibilities has been discussed in the thesis in details, finally, the real-time test system has been developed successfully and good test result got. With practical test, the system runs stably, it not only meets real-time test request, but also can get wave height differential rate of 0.01 mm, it reaches the initial expectation made in the thesis. The experiment results have good practical values to model test research of TAPW.