Experimental Investigation And Numerical Simulation Of Influence Of Aeration On Scour

The existing results about scour hole was summarized. Experiments was made about the influence of aeration on scour,the dynamic pressure on the original riverbed and the scouring hole bottom,and the influence of aeration on the dynamic pressure and the velocity of submerged jet. Scour was simulated by numerical model. The main contents and conclusions are as follows:1. The dynamic pressure on the original riverbed and the scour hole are measured. The results show that the characteristics of dynamic pressure in the scour hole are the same as that on the original riverbed.2. Experiments about the influence of aeration on the dynamic pressure on the original riverbed show,aeration will obviously increase the fluctuating pressure on the original riverbed.3. Experiments about the influence of aeration on the dynamic pressure on the bottom of scour hole show,the influence of aeration on the dynamic pressure on the bottom of scour hole is ruleless.4. Experiments about the influence of aeration on scour hole show,aeration decrease the scour depth. The relationship between the air concentration and the scour depth can be expressed as an exponential function. Aeration does not affect the shape of scour hole. The ratio of the length to the depth of scour hole decreases with the increasing scour depth,in spite of the reason is the increase of the air concentration,the decrease of the jet velocity or the decrease of the jet thickness.5. Governing equations of the aerated jet flow are established. Experimentsabout the influence of aeration on the velocity of the submerged jet was made. It has been proved that the main reason of the influence of aeration on scour is the more rapid decrease of the velocity of the submerged velocity.6. A set of mathematical model was developed and the scouring was simulated. The calculated results accords with the experimental data very well.