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Old   September 23, 2010, 17:11
Default help me in wall motion,please!
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I want to consider motion of an airfoil with some velocity and his frame(this is frame unstationary, not dynamic mesh). Please tell me how to set BC on the wall and in the Fluid(frame). Thank you for reading!
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Old   September 29, 2010, 18:09
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Someone can tell me, please, how to set simple motion of train in tunnel with any velocity. I complicated several days. A model is:

Thank you for reading! :-)

Last edited by lehoang_mai; October 5, 2010 at 04:46.
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Old   October 4, 2010, 02:05
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explain your problem, if possible with pictures
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Old   October 4, 2010, 05:40
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Dear - mAx-!
My problem similar problem in last post, but in 3D. For simple, I modeled 2D square in big rectagular(tunnel),picture explained, top and botton boundarys are walls, right is outlet and left - inlet. Usual, we put some velocity(50m/s) in INLET, but I want to set motion of 2D square toward with same velocity(stationary problem), and see which difference in this. I known, for this necessary set: wall(square)>moving wall> components> put 50m/s in x-velocity, then going to Initialize>Initialize... this I haven't put nothing, I applied and iterated. I known, I missed. Please, tell me how to set for this.
Best wish for you!
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Old   October 4, 2010, 05:56
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if you don't use moving mesh then you only have to set the velocity in the wall motion panel (as you did)
what is the problem?
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Old   October 4, 2010, 12:55
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Thank you for your reply!
I don't know, where I'm losing?
I putted 50m/s in INLET, contour of Velocity Magnitude:
http://www.cfd-online.com/Forums/mem...contour-v1.jpg
I putted 50m/s in moving wall(as I talked you), It is:

I think contours are similar together. I'm right?
Sorry for stupid!

Last edited by lehoang_mai; October 5, 2010 at 04:28.
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Old   October 5, 2010, 02:16
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I don't see anything.
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Old   October 5, 2010, 04:38
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Quote:
Originally Posted by lehoang_mai View Post
Thank you for your reply!
I don't know, where I'm losing?
I putted 50m/s in INLET, contour of Velocity Magnitude:

I putted 50m/s in moving wall(as I talked you), It is:

I think contours are similar together. I'm right?
Sorry for stupid!
I took new photos. Thank you very much for reply!
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Old   October 5, 2010, 04:45
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post also the scale, and describe the boundary conditions you set for both cases
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Old   October 5, 2010, 04:58
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This is pisture of problem

In fisrt case, I have put 50m/s in INLET, Models>Viscous>k-e standar, Initialize: computer from INLET, and contour of Velocity Magnitude
In second case, Models the same, I didn't put 50m/s in INLET, a putted 50m/s in square(wall)>moving wall>Components>X-Velocity, but contour of velocity magnitude is:

Please tell me, where I'm lossing?
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Old   October 5, 2010, 05:13
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In the 2nd case what did you set at the inlet?
Check the mass conservation (report/mass flow rate @ inlet and outlet), normally in incompressible case you should have a net mass flow of 0 (inlet - outlet)
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Old   October 5, 2010, 05:39
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In 2nd case, I did't set INLET and also Initialize>Initialize , a I have set only on square. In process before an Iteration lie message "reversed flow in 55 faces on outflow 3.".
As you talked, I controlled mass flow rate, but not received.
Mass Flow Rate (kg/s)
-------------------------------- --------------------
inlet 0
outlet 5.3969416e-09
Net 5.3969416e-09
I'm very .
Thank you very very much for your help!
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Old   October 5, 2010, 05:54
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So you let the inlet with 0 m/s, which means you have a flow entry without massflow rate. (not correct)
Since both cases are the same (reference point of view) you need to compute your model like your first case (inlet velocity and stationnary square). In this case you get a massflow rate which flows in your domain, and one which flows out
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Old   October 5, 2010, 06:03
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Dear -mAx-!
With 1st case, I got it. This is as experimental flow in tube. But my problem is set motion of square(as natural flow - I mean no set velocity in INLET), Please, tell me how to solve 2nd case!
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Old   October 5, 2010, 06:12
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then switch to moving mesh and unsteady solver. And you need another boundary condition for your inlet, but I don't know what. (maybe something like presure far field or whatever)
Check tutorials about moving mesh.
Maybe other people could treats your problem in a different way, but I don't know how
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Old   October 6, 2010, 17:14
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Dear -mAx-! Thank you very much for help.
I think I got it. This is my set:
- Fluid> moving reference frame> set Translational X-velocity to 50m/s.
- Wall> moving wall> adjacent to the cells zone> set zero of velocity.
- Iterate.
Regards.
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