6DOF - 1DOF translation large forces
 

Hi all,

So im new to fluent, and i want to simulate the opening of a check valve by simulating a spring force on one face of the valve and the fluid pressure on the other. I want to do this in 2D
I have set this up with the 6DOF solver and set it to 1DOF translation with a small spring constant of 20N/m. The fluid is water, and i've set a velocity inlet based on a UDF where the flow is = 10*current_time, up until 0.02s when the flow is 0.2m/s. The outlet is a pressure outlet with 0pa static pressure.

My problem is that unless i use very very small time steps of 1e-10 s, even at very small flow rates, the solver spits out huge resulting forces on the face of the valve. This only happens for fluids with high densities, if i use air for example, i am able to simulate the valve movement just fine.

What could the issue be?

i have uploaded a pic of the pressure contour. The inlet is to the left. This is at a time step in the order of 1e-09 seconds.

hi
show boundary conditions on the picture
when you used air, have you seen the valve seat moves?

Hi
I have the same problem. In every time steps force value going to infinity.
I'm so glad if someone help me.
Thanks

Try solution stabilization.
In dynamic mesh panel, for the selected zone (I guess, wall absorbing the pressure forces), you will have a panel called Solution stabilization, try the volume based, starting from small Scale factor values

How to use damping in the 1DOF spring case??