my problem is about two phases flow:in a extenal circulate reactor,the reactor is filled with some water,then the air spray into the reactor from the bottom,the water is moved follow the air. now i use the eulerian-eulerian model to simulate the experiment.but the result is not fit the fact:in the experiment,the water can circulat at a low air velocity( 4m/s ),but in the simulation,the water won't circulat until the air velocity reach 19m/s. now i cound't find what's wrong with me ,i am so anxious for your help!!!

I am not an expert on the multiphase field, but if you say that you inject air into water, you would expect the air to form bubbles of various sizes, and the momentum exchange between the phases would to a large extent be because of drag forces of the bubbles. Now, with a standard Euler-Euler approach I am not sure if you get other forces than pure shear stresses produced in the fluid field, and those are assumeably smaller, and you will need a larger air mass flow to make things rumble. How about VOF model?

Regards Anders

thank you

as you have said that the water will move follow the air by the momentum exchange,as the air is sprayed into the reactor continuously,it can produce bigger momentum,so it should stimulate the water to move,but i don't know why i can't get the result.

the vof model i have tryed,but it will disconverge soon,i think the vof model can use in the free surface trace not the mix multiphase

sincere zhaofei