Research And Application Of Flow Visualization Technique In The Seabuuckthorn Plant Flexible Dam Outdoor Fluid Measurment

Flow visualization and the quantitative measurement of flow velocity field is one of the major projects faced by most fluid researchers. In order to solve this problem, there have been a variety of fluid measurement techniques emerged as the times require. Began with the Hot Wire Film Anemometer(HWFA) human beings invented in the beginning of last century, to Particle Image Velocimetry (PIV) shaped by combining computer with optics technique, developing for about 70 years, the fluid field measurement has gradually got over the disfigurement of the single-point esculent measurement. However, the major researches of many domestic scholars are the PIV applications for the indoor mini-type experimental bed, which experimental conditions are very rigorous. In order to impose and extend this advanced fluid field measurement technique better, and to explore the effect for using in outdoor large-scale experimental field, this research, supported by the Yellow river Seabuckthorn Plant Flexible Dam zoology project in grit area (The National Natural Science Fund), use PIV technique to observe the configuration changes of fluid field in Seabuckthorn Plant Flexible Dam, The work accomplished are as follows:(1) Based with the principium of PIV technique, this paper designed a suit of experimental equipment for collecting images, which adapts to observe the outdoor fluid field;(2) The PIV technique has been studied. It includes the pretreatment of digital images, the particle image velocimetry arithmetic and the data post processing. Combined with the PIV technique, this paper compiles process by using computer language to reconstruct the water flow movement characters of the Seabuckthorn Plant Flexible Dam, which includes its fluid field calculation;(3)Based with the experimental data, it analyzes and studies the function of the Seabuckthorn Plant Flexible Dam in holding up and fixing up the sand rocks, which provides the sustentation in both theoretically and technically for plant flexible dam in holding up and fixing up the sand rocks, in the angle of water flow dynamics; and in the meanwhile, it explores the feasibility for applying PIV in measuring the fluid field of outdoor large-scale irrigation project models or crude water body.The main conclusions can be draw from paper as follows:(1) This paper make the use of PIV technique to measure the instantaneous velocity of the whole bed, then intercept the average velocity of each monitoring cross section. By drawing the velocity graph, it is found that the water flow which from inflowing the bed to outflow has experienced a process described as follows: increasing firstly and later decreasing, and then slake increasing until becoming stabilization.(2) In applying PIV technique to outdoor large-scale irrigation project model, its experimental setup and the character of experimental equipment have grate influence to test results, and sometimes even can determine weather the test is successful or not. However, based with the parallel analysis of fluid field measurement result in the Seabuckthorn Plant Flexible Dam, and the test results of Sichuan University and Sin kiang Agricultural University, this study believe that it is feasible to extend the PIV technique to outdoor flow velocity field observation.