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Posted:
1 decade ago
2010年8月9日 GMT-4 上午2:30

The inlet flowrate is too steep for the start I would assume. The workaround is to start from very low and then ramp it up to your desired velocity, or run a steady-state simulation with your initial target velocity and use it as initial condition.

The inlet flowrate is too steep for the start I would assume. The workaround is to start from very low and then ramp it up to your desired velocity, or run a steady-state simulation with your initial target velocity and use it as initial condition.

Rinaldo Gonzalez Galdamez
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Posted:
1 decade ago
2010年8月9日 GMT-4 下午2:01

Hello,

I am having a similar problem with my model. The difference is that it is a multiphase flow. I am using the level-set method. All the subdomain settings and boundary conditions seem to be fine. I initialize the level-set function as it is recommended in the user guide and use that initial value for the transient solution. I keep getting the same error: " Failed to find consistent initial values. Last time step not converged". Could it be that the inlet pressure is too big? Could it be the solver? the mesh?

Thanks in advance.

Hello,
I am having a similar problem with my model. The difference is that it is a multiphase flow. I am using the level-set method. All the subdomain settings and boundary conditions seem to be fine. I initialize the level-set function as it is recommended in the user guide and use that initial value for the transient solution. I keep getting the same error: " Failed to find consistent initial values. Last time step not converged". Could it be that the inlet pressure is too big? Could it be the solver? the mesh?
Thanks in advance.

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Posted:
1 decade ago
2010年8月9日 GMT-4 下午9:53

I am not sure exactly what I done but I am trying to explain what happend.

The result looks fine and maybe I solved this problem. However I am not sure the procedure.

What I done for this problem is that I set up stationary solver 1 and transient solver1 under study 1 and

right click the study 1 and click show basic configuration for the study 1. And I changed the method from iterative to direct.

And I run and get the result without any error. And the result looks fine.

I think this may be the procedure to setup for initial value for transient solver.

But unitl now I am not sure that this setting make the stationary solver run with the initial value from transient case at t=0.

Is there anyone can confirm this?

Thanks in advance.

I am not sure exactly what I done but I am trying to explain what happend.
The result looks fine and maybe I solved this problem. However I am not sure the procedure.
What I done for this problem is that I set up stationary solver 1 and transient solver1 under study 1 and
right click the study 1 and click show basic configuration for the study 1. And I changed the method from iterative to direct.
And I run and get the result without any error. And the result looks fine.
I think this may be the procedure to setup for initial value for transient solver.
But unitl now I am not sure that this setting make the stationary solver run with the initial value from transient case at t=0.
Is there anyone can confirm this?
Thanks in advance.

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Posted:
1 decade ago
2010年8月10日 GMT-4 上午2:16

You use usually the steady-state case as an initial value for the transient case (I think you meant the other way around?).

So first setup your st.st solver, initial values set to 0. Then your transient solver has the initial values set to solution, and the sol is from the st st solver. You can also have a "store solution" on the st.st solver to keep the results and refer to it later.

You use usually the steady-state case as an initial value for the transient case (I think you meant the other way around?).
So first setup your st.st solver, initial values set to 0. Then your transient solver has the initial values set to solution, and the sol is from the st st solver. You can also have a "store solution" on the st.st solver to keep the results and refer to it later.

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Posted:
10 years ago
2010年10月5日 GMT-4 下午11:28

Hi,

I'm heading down the same road, but am stuck on something even simpler. In the attached, I solve first for purely stationary "p0" and then want to use that as the initial value for subsequent transient value "p".

If you look at "Line Graph 1", you can see that the limit solution for large time is correct, but it has picked up some seemingly random function for t=0.

Any suggestions appreciated,

Thanks, John

p.s. Duh. Apparently all it took was me posting here. This is working now. I changed the selections for the initial values in dependent variables 2. Initial values now set to "initial expresion" .... second attached file is the good one.

Hi,
I'm heading down the same road, but am stuck on something even simpler. In the attached, I solve first for purely stationary "p0" and then want to use that as the initial value for subsequent transient value "p".
If you look at "Line Graph 1", you can see that the limit solution for large time is correct, but it has picked up some seemingly random function for t=0.
Any suggestions appreciated,
Thanks, John
p.s. Duh. Apparently all it took was me posting here. This is working now. I changed the selections for the initial values in dependent variables 2. Initial values now set to "initial expresion" .... second attached file is the good one.

Ivar Kjelberg
CSEM SA (CH)
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Posted:
10 years ago
2010年10月6日 GMT-4 上午2:45

Hi

have you niticed that you have two different pressure values for Pressure 2 in the two Darcy dl1 and dl2. I would expect them to be equal no ?

--

Good luck

Ivar

Hi
have you niticed that you have two different pressure values for Pressure 2 in the two Darcy dl1 and dl2. I would expect them to be equal no ?
--
Good luck
Ivar