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Figure 2: Flow over 180 degree turn in flocculation tank
We compared the back step flow using K-e, K-W SST, K-e realizable, K-e RNG, RSM turbulence models. We need to pinpoint the reattachment points of all the turbulence models so that we can compare the reattachment ration with the experimental data.
Plotting the derivative du/dy, the change in direction of velocity in x direction with respect to y at the wall, we will be able to accurately pinpoint the reattachment point. At the wall, separation flow will give negative du/dy and and the flow reattaches, the du/dy will reach zero and becomes positive. Figure 3 shows the derivative of du/dy vs x direction for different turbulence model.
Table 1 shows the comparison results of different turbulence models.
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