Theoretical Analysis And Experimental Research Of Vertical Two-dimensional Diffusionconcentration Distribution From Complex Bank

First the paper presents the theory formula of two-dimensional diffusion concentration distribution caused by the instantaneous surface pollutant source whenβ is an odd number. The contaminants concentration of water surface pollutant source of gradient bank takes orderliness of a periodicity that is multiple of the corner field mapping coefficient β=4 combined with concentration distribution formula of even number mapping coefficient of an angular field. The article compared the water surface pollutant source with the shore line source. The results show that contaminants are advantageous to diffuse and spread more widly in the condition of water surface pollutant source while contaminants are easy to get together in the nearshore area range and distribute smaller range and coastal zone pollutant is serious in the condition of line source.Second, on the basis of theoretical and experimental research on pollutant concentration distribution discharged from the vertex of angular area for sloped-bank and facade flume experiment system, the complex bank vertical 2-D changing slope pollutant diffusion experiment device was done. The paper carry on the experiment of concentration distribution of sloped wave bank and sloped wave ladder bank and sloped ladder bank. There are following the results:(1) In the area of sloped wave bank, the speed of concentration distribution become fast as the grid vibration frequency become high. The pollutant range is becoming larger as the time goes on. The water surface pollutant concentration is smaller with the abscissa farther, the concentration distribution of vertical direction with the depth of water monotonic decrease. The speed of transverse diffusion is faster than vertical diffusion. The result shows the distribution characteristics that the distribution of water surface is faster. The pollutant concentration of θ=30° sloped wave bank area is higher than the pollutant concentration which is in θ=45° sloped wave bank area in the same conditions. There is big whirlpool in the area of θ=45°sloped wave bank around, the concentration of pollutant decrease and then increase along the bank while there is not whirlpool in the area of θ=30° sloped wave bankaround, the concentration of pollutant monotonic decrease along the bank.(2) In the area of sloped wave ladder bank, the speed of concentration distribution become fast as the grid vibration frequency become high. The pollutant range is becoming larger as the time goes on. The water surface pollutant concentration is smaller with the abscissa farther, the concentration distribution of vertical direction with the depth of water monotonic decrease. The form of distribution ladder above area is similar to the form in the area of sloped wave bank when the water depth of ladder above h=0.5m; The transverse diffusion is obvious while the vertical diffusion is not. In the same condition, the concentration along the water surface of slope wave ladder bank is nearer than the slope wave bank. There is a big difference between the different water depth. There in no obvious distribution characteristics in the right area of ladder when h=0.5m while is obvious when h=0.2m and h=0.3m. It is resulted from the size and effect coverage of whirlpool. The whirlpool play an important role in concentration distribution. The size of whirlpool largen with increasing of water depth and grid vibration frequency.(3) In the area of sloped ladder bank, the speed of concentration distribution become fast as the grid vibration frequency become high. The pollutant range is becoming larger as the time goes on. There is not much difference between the speed of transverse diffusion and vertical diffusion when the water depth of ladder above h=0.5m; The speed of transverse diffusion is fast and the vertical diffusion is not obvious while in the right area of ladder. There is obvious vertical obvious distribution characteristics when h=0.2m and h=0.3m. Comparing with the distribution speed of sloped wave ladder bank area, the distribution speed of sloped wave ladder bank area is slower. There is also whirlpool in the right ladder area, but the size of whirlpool is smaller than that in the area of sloped wave ladder bank.The paper makes a study of pollutant concentration distribution of complex bank,which promotes the development of environmental hydraulics. It is useful for the calculation of mixing zone and water environmental carrying capacity and water environment function zone. It has a wildly application prospect to promote carrying out the license system water pollutant mixing zone.