[vinz]

Dear all

Here is what I am doing.
I did a first computation using simpleFoam on a "empty" shape that you can see in the picture below.


Up to that point everything is fine and results look good.
My goal is to place a valve on the right part of the shape with an overpressure inside. To do that I created a new mesh, I chose a pressure of 500 Pa in all the field and then I used mapFields with the precedent result. This way, the pressure is equal to 500 inside the shape and is equal to the previous result everywhere else. (See picture below).



Then I want to start my computation with pimpleFoam with still the same wind coming from the right (4m/s) in order to see if my over pressure actually decreases through the valve and what the flow looks like in this part.

My problem here is that at the first time step the pressure in the shape becomes quickly equal to the "stagnation" pressure I found in my previous computation. Without really creating any flow through the valve. Even for low timeSteps, the behavior does not look correct.

I already ran some computations with non uniform initial flow field using rhoPimpleFoam with quite good results but with this case I don't manage to get what I want.
I have to add that my computation is axisymmetric.

Does anyone have an idea on this ?

Vincent

[vinz]

any idea on what's going on?

[michielm]

The images are not visible. Could you post them through the image include of the forum?!

[vinz]

Thank you for pointing that out.

It is actually very strange since I can see the image on linux but not on my Mac.

Here are the links toward images, and as you can see I have use the forum attachment tool since they are hosted on CFD-online:
http://www.cfd-online.com/Forums/att...1&d=1353921281


http://www.cfd-online.com/Forums/att...1&d=1353921472


http://www.cfd-online.com/Forums/att...1&d=1353921481

[michielm]

Originally Posted by vinz

Thank you for pointing that out.

It is actually very strange since I can see the image on linux but not on my Mac.

Here are the links toward images, and as you can see I have use the forum attachment tool since they are hosted on CFD-online:
http://www.cfd-online.com/Forums/att...1&d=1353921281


http://www.cfd-online.com/Forums/att...1&d=1353921472


http://www.cfd-online.com/Forums/att...1&d=1353921481

Still can't see them. I get this message: 'Invalid Attachment specified. If you followed a valid link, please notify the administrator'

Do you have any external place to put them so I can look at them there?

[vinz]

let's try it for the last time.

Now normally it should be even visible on the first message.

[michielm]

Yes, now I can see the images.

I'm not sure why this would happen. What boundary conditions do you have on the valve walls?!

[vinz]

I treat them as no slip walls.

[vinz]

I am really stuck with this.

Does anyone have any idea?

[vut]

Dear VINZ,

Your post interested me.

I am new Foamer with little experience and I am searching for initializing a LES simulation using pimpleFoam from a solution of simpleFoam.

That's would be great if you can give me some details and steps to follow.

Thank you in advance,

VUT

Originally Posted by vinz

Dear all

Here is what I am doing.
I did a first computation using simpleFoam on a "empty" shape that you can see in the picture below.


Up to that point everything is fine and results look good.
My goal is to place a valve on the right part of the shape with an overpressure inside. To do that I created a new mesh, I chose a pressure of 500 Pa in all the field and then I used mapFields with the precedent result. This way, the pressure is equal to 500 inside the shape and is equal to the previous result everywhere else. (See picture below).



Then I want to start my computation with pimpleFoam with still the same wind coming from the right (4m/s) in order to see if my over pressure actually decreases through the valve and what the flow looks like in this part.

My problem here is that at the first time step the pressure in the shape becomes quickly equal to the "stagnation" pressure I found in my previous computation. Without really creating any flow through the valve. Even for low timeSteps, the behavior does not look correct.

I already ran some computations with non uniform initial flow field using rhoPimpleFoam with quite good results but with this case I don't manage to get what I want.
I have to add that my computation is axisymmetric.

Does anyone have an idea on this ?

Vincent