[cbrian]

Hello,
I have a total pressure outlet profile that I'd like to use as the inlet boundary condition for another case. The issue is that the meshes are completely different. Ideally I'd like to use a circumferentially-averaged PT profile as the inlet BC but it seems this isn't possible in CFX.
What is the best way of going about this?
Thanks for any help you can give me.

[diamondx]

In CFD-post, you can export a boundary profile, then use it as inlet boundary profile in CFX. Basically you will use, the "file - > export" function in cfd-post, then "tools -> initialize profile data" in CFX. For a mass flow for examples, the variable is dependent on x,y,z. I SUPPOSE even if your mesh changes but its position did not change, it can work... Hope it can help

[Opaque]

Complementing diamondx response, if your case is a turbo machine you can use TurboPost do compute the circumferentially averaged profile. Such profile is radial only now, correct ?

You can then export as diamondx explained your radial profile, and use it in CFX-Pre as usual.

[cbrian]

Originally Posted by diamondx

In CFD-post, you can export a boundary profile, then use it as inlet boundary profile in CFX. Basically you will use, the "file - > export" function in cfd-post, then "tools -> initialize profile data" in CFX. For a mass flow for examples, the variable is dependent on x,y,z. I SUPPOSE even if your mesh changes but its position did not change, it can work... Hope it can help

Unfortunately both the mesh and the position changed. I've tried using the profile anyway, but CFX diverged pretty quickly.

Originally Posted by Opaque

Complementing diamondx response, if your case is a turbo machine you can use TurboPost do compute the circumferentially averaged profile. Such profile is radial only now, correct ?

You can then export as diamondx explained your radial profile, and use it in CFX-Pre as usual.

This is indeed a turbomachine, I'm trying to use the output from a centrifugal impeller case as the input to the diffuser. I'll try using TurboPost, I wasn't even aware it existed but it probably came with our CFX package.

[cbrian]

Originally Posted by Opaque

Complementing diamondx response, if your case is a turbo machine you can use TurboPost do compute the circumferentially averaged profile. Such profile is radial only now, correct ?

You can then export as diamondx explained your radial profile, and use it in CFX-Pre as usual.

I am able to pull a radial profile using TurboPost by generating a Circumferential Turbo Chart with a streamwise location of 0.99. However, I need the profile to be averaged over the span, which I do not see a way to do. Is this possible?

[Opaque]

Not sure what your goal of using the profile of the outlet as the inlet profile for the next simulation is ? If you average the profile on both directions: circumferential and span, you may as well put a uniform value that ballpark the average you want. Then, there is no need for exporting/importing.

The idea of using profile from one simulation to another is to keep as much information as possible from the "real distribution upstream" instead of guessing a distribution downstream.

[Thomas MADELEINE]

Hi all,
just to add some little thing to the discussion
when you import a profile for a boundary it is read as a function (XxYxZ -> value) so it is interpolated betwen each point you give (your ancient mesh) and read to your new mesh

moreover if you know the change you have done in your geometry you can adjust your profile quite easily in the BC setup: just replace X,Y,Z by the value you want
or create new variable to match the old profile with the new BC, exemple: X0 = X*cos(theta) + Y*sin(theta)

I suppose it works the same in the Turbo module

[cbrian]

Originally Posted by Opaque

Not sure what your goal of using the profile of the outlet as the inlet profile for the next simulation is ? If you average the profile on both directions: circumferential and span, you may as well put a uniform value that ballpark the average you want. Then, there is no need for exporting/importing.

The idea of using profile from one simulation to another is to keep as much information as possible from the "real distribution upstream" instead of guessing a distribution downstream.

I got a little confused in my description of what I was looking for - what I wanted was a spanwise profile of total pressure, averaged circumferentially.
For future reference of anyone who finds this thread: this was possible to do using the Hub to Shroud Turbo Chart using the streamwise location mode.

[cbrian]

Originally Posted by Thomas MADELEINE

Hi all,
just to add some little thing to the discussion
when you import a profile for a boundary it is read as a function (XxYxZ -> value) so it is interpolated betwen each point you give (your ancient mesh) and read to your new mesh

moreover if you know the change you have done in your geometry you can adjust your profile quite easily in the BC setup: just replace X,Y,Z by the value you want
or create new variable to match the old profile with the new BC, exemple: X0 = X*cos(theta) + Y*sin(theta)

I suppose it works the same in the Turbo module

Thanks - I think specifying the surface I'm applying the new inlet BC to would be fairly easy as it's at a constant radius from the axis of rotation. However, what I have now is a spanwise profile of circumferentially-averaged total pressure. It seems that CFX does not have a method of using this, as it only wants a profile specifying the conditions across the entire inlet. Any idea if there's a way of using this profile?

[Opaque]

I think you are confusing mesh coordinates with turbo coordinates. Once you obtain the spanwise profile by circumferentially averaging the previous solution, what you really have is a f(x,y,z) that when plotted show circumferential bands, but still a function of x,y,z on the surface.

Just export the spanwise profile you got as a (x,y,z) function, and import it in CFX-Pre. Once you hook it up on your inlet, you can visualize what you got and I bet you will see the spanwise distribution you expect.