Still standing water expand strongly
I had a 2D case in which a non-Newtonian fluid slides into a stationary Newtonian fluid.But I noticed a strong expansion in still water.At first I thought the expansion was caused by the sliding body crashing into the still water.However, when I tried to fill only the static Newtonian fluid without setting the non-Newtonian fluid sliding body in the calculation example,
I found that the static water still showed strong expansion phenomenon. I am not understanding why it happens.
Has anyone ever had a similar problem in the simulation？