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Search took 0.00 seconds. Search: Posts Made By: ghorrocks
Forum: CFX August 3, 2013, 08:48
Replies: 38
Views: 5,009
Posted By ghorrocks
No, you should not source terms to model what I...

No, you should not source terms to model what I understand you are trying to model.

As the porous model is not working on a simpler model I would concentrate on getting it working on the simple...
Forum: CFX August 2, 2013, 08:25
Replies: 38
Views: 5,009
Posted By ghorrocks
I have already said my suggestion two times - so...

I have already said my suggestion two times - so here it is for a third time. Have you simplified your model (ie just use a newtonian fluid, and a simple geometry) to test that the porous material...
Forum: CFX August 1, 2013, 20:42
Replies: 38
Views: 5,009
Posted By ghorrocks
OK - so with a permability so low, will you get...

OK - so with a permability so low, will you get any flow?

In post #27 I recommended you simplify the model to get the components working. Have you done this?
Forum: CFX August 1, 2013, 18:04
Replies: 38
Views: 5,009
Posted By ghorrocks
Rather than randomly trying permabilities, how...

Rather than randomly trying permabilities, how about working out what the permability actually is?
Forum: CFX August 1, 2013, 02:28
Replies: 38
Views: 5,009
Posted By ghorrocks
Slip or no slip should not matter on the porous...

Slip or no slip should not matter on the porous interface. If you are getting no flow in the porous region you have a more fundamental problem with your simulation.

I note your permeability is...
Forum: CFX July 29, 2013, 21:57
Replies: 38
Views: 5,009
Posted By ghorrocks
Time Step: Do not guess, invariably you will get...

Time Step: Do not guess, invariably you will get it wrong. Use adaptive time stepping, with 3-5 coeff loops per iteration. Then the solver will find the correct time step size.

Free slip: sure,...
Forum: CFX July 29, 2013, 08:04
Replies: 38
Views: 5,009
Posted By ghorrocks
Where do you get the time step size from? Did you...

Where do you get the time step size from? Did you actually do something to show that time step was required or did you just guess?

You have your artery wall set to solid morphology. You probably...
Forum: CFX July 29, 2013, 00:13
Replies: 38
Views: 5,009
Posted By ghorrocks
So it looks like it is not solving the fluid...

So it looks like it is not solving the fluid equations in the porous region. Can you post your CCL?
Forum: CFX July 28, 2013, 19:43
Replies: 38
Views: 5,009
Posted By ghorrocks
What is momentum and mass -2? Is that fluid flow...

What is momentum and mass -2? Is that fluid flow in the porous domain?
Forum: CFX July 19, 2013, 06:13
Replies: 38
Views: 5,009
Posted By ghorrocks
That has to start with you - you say fluid goes...

That has to start with you - you say fluid goes through the porous wall all over. So what controls it? You need some function to drive it. A defined flux? Maybe a concentration gradient? Maybe a...
Forum: CFX July 18, 2013, 08:57
Replies: 38
Views: 5,009
Posted By ghorrocks
The the inlet should be 0.2m/s (or a time...

The the inlet should be 0.2m/s (or a time function with an average of 0.2m/s), the outlet a pressure boundary at 0Pa and the other wall of the vessel has some function to control the amount of fluid...
Forum: CFX July 17, 2013, 18:49
Replies: 38
Views: 5,009
Posted By ghorrocks
The fluid flow path is important. How much flow...

The fluid flow path is important. How much flow goes through the walls? And what is the source of the fluid coming through the walls (ie everywhere, or a specific location)? How much through the...
Forum: CFX July 17, 2013, 06:22
Replies: 38
Views: 5,009
Posted By ghorrocks
Your last post seems to suggest you have no idea...

Your last post seems to suggest you have no idea how to model this at all. In this case can you post an image of what you intend to model - all of it, not just one little bit - and show what the flow...
Forum: CFX July 17, 2013, 03:00
Replies: 38
Views: 5,009
Posted By ghorrocks
If the inlet is 0m/s there is no flow, so of...

If the inlet is 0m/s there is no flow, so of course the pressure is 0Pa.
Forum: CFX July 16, 2013, 18:53
Replies: 38
Views: 5,009
Posted By ghorrocks
You are using a wall as your outlet boundary !!??...

You are using a wall as your outlet boundary !!?? This is obviously a bad idea.
Forum: CFX July 15, 2013, 20:29
Replies: 38
Views: 5,009
Posted By ghorrocks
Why have you set the outlet pressure to be the...

Why have you set the outlet pressure to be the average of the outlet pressure? This sounds wrong to me - you should set it to the known fixed outlet pressure value (probably 0Pa).
Forum: CFX July 14, 2013, 22:53
Replies: 38
Views: 5,009
Posted By ghorrocks
Can you successfully run simulations with no FSI...

Can you successfully run simulations with no FSI or mesh motion? Simplify your simulation down to what does run, then add the complexity one bit at a time - checking it works every time you add...
Forum: CFX July 13, 2013, 18:42
Replies: 38
Views: 5,009
Posted By ghorrocks
If you only want to know the pressure drop (and...

If you only want to know the pressure drop (and the flow is incompressible) then pressure is relative. This means you can specify any pressure you like so it might as well be zero.

There are many...
Forum: CFX July 13, 2013, 07:27
Replies: 38
Views: 5,009
Posted By ghorrocks
If you do not know the conditions at the exit...

If you do not know the conditions at the exit boundary then you cannot perform a simulation. You MUST know the conditions at the exit to perform a simulation. So if you do not know the conditions...
Showing results 1 to 19 of 19

 
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