Abstract
In order to improve water quality in stagnant stream, we invented consecutive slit walls. As to the parameter of slit wall, slit width, slit location and streamwise interval of walls were changed. The flow structures in a slit-wall region were measured by using PIV method and the effects of flow structures on the concentration of dissolved oxygen was investigated numerically. By setting the slit walls, fast meandering flow and accompanying recirculating vortices were generated. The average velocity in the slit-wall region increases with a decrease of the slit width and as the slit location approaches to the side wall. When the slit walls are submerged, the average velocity in the slit-wall region becomes significantly small, the flow structure becomes three-dimensional and the vertical velocity increases. The depth-averaged 2d numerical model can reproduce the flow structures in the slit-wall region. It is demonstrated that the dissolved oxygen increases in the center region of recirculating vortices and the total concentration increases as the recirculating area becomes larger.
