I simulate the bubble's movement in the water and the bubbles are regard as discrete elements. At the start of calculation, the bubble velocity is not equal to 0, and the liquid velocity is equal to 0, the pressure gradient of the liquid flow field is 0, therefore the buoyancy of air bubbles is 0, but the drag force is not 0, So if the bubbles inject into the flow field in the horizontal direction ,they will be move downward under the drag effect, which is obviously not realistic. How to solve this problem?
Can I add a control to make the drag force works when the simulation time reach a fixed value to fix this problem? How to realize it?
Yours
Zhao