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February 15, 2018, 17:23 |
6DOF - 1DOF translation large forces
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#1 |
New Member
Emil Pedersen
Join Date: Feb 2018
Posts: 1
Rep Power: 0 |
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. |
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February 18, 2018, 08:19 |
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#2 | |
Member
ram
Join Date: Apr 2013
Posts: 37
Rep Power: 13 |
Quote:
show boundary conditions on the picture when you used air, have you seen the valve seat moves? |
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March 5, 2022, 10:40 |
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#3 |
New Member
mohammad
Join Date: Dec 2021
Posts: 10
Rep Power: 4 |
Hi
I have the same problem. In every time steps force value going to infinity. I'm so glad if someone help me. Thanks |
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March 5, 2022, 19:16 |
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#4 |
Member
Marcin
Join Date: Jun 2016
Posts: 98
Rep Power: 10 |
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 |
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May 15, 2024, 07:02 |
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#5 |
New Member
CFD
Join Date: May 2022
Posts: 15
Rep Power: 4 |
How to use damping in the 1DOF spring case??
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Tags |
6dof, check valve, large force |
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