Pressure Outlet setting
Hello everyone,
I have a problem about simulating a filter with a pressure loss boundary condition (use pressure outlet as my boundary condition), a expectable pressure loss is about 8 to 14 psi. My model having 4.45E+6 cells is meshed by Patran. I can simulate it with 10 psi pressure loss (inlet 10 psi , outlet 0 psi), but get a floating point exception: [overflow] at first few iterations with 11 psi pressure loss (inlet 11psi, outlet 0psi). However, i get the same result when i set inlet and outlet for 11psi and 5psi. It seems that i can not set a pressure more than 11psi. With another model having 9.94E+6 cells meshed with STAR-CCM+ 5.02, I get the same problem as i set a pressure over than 0.2 psi. :-( All settings are default values, is there any setting i can try to simulate with a higher pressure ? Thank you, all!! CoG |
Ramp the pressure...
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Thank you for your answer!!
It works now. |
hello,
I set under-relaxaiton factors of pressure & velocity small during first several iterations , then set them for default value. The simulation ran expectably about 320 iteration and all residuals were belows 1E-4, but residuals went up after 350 iterations. All residuals were between 1E+1 and 1E-2 at 6xx iteration. I have another problem about floating point exception [Invalid operation] now. :-( I try to ramp the factor, but it doesn't work. It there another way? CoG |
hello,
I have a question about initial condition of velocity and pressure outlet boundary conditions. I simulate a steady pipe flow through a filter with pressure outlet and notice that the pressure contains velocity energy. If I set a velocity initial condition, would it help the simulation converge ? thanks, CoG. |
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