laminar steady state using simpleFoam

monti · January 5, 2011, 12:31

Hello,

I want to run a simulation of a laminar waterflow in a channel using simpleFoam, but I get weird results.

Here is what I have done:

Changing file RASProperties and set RASmodell to laminar, turned off turbulence and printcoeffs.

Changed nu in transportproperties to 1e-06 for water.

Setting the boundaryconditions in 0/U to 0.5 m/s for the inlet, in 0/p boundarycondition for the outlet = 0.

I set the endtime in controlDict to 10 seconds (why do I have to set an endtime anyway, it is not transient?).

I get as a result a velocity of 3000.

Has anybody an idea what I do wrong?

Bye
Mark

monti · January 5, 2011, 12:51

Please forget everything so far! Endtime is used for iterations, setting it to a higher number everything works fine all of a sudden

Bye
Mark

monti · January 6, 2011, 12:19

I stuck! I thought I found the mistake, but I didn't. My results are still way too high, and I have no idea what to do. Can someone help me?

I simply want to simulate a steady state laminar flow in a channel.

Bye
Mark

monti · January 13, 2011, 14:09

Who has used simpleFoam to simulate a steady state waterflow in a channel? I really need some help.

Bye
Mark

santiagomarquezd · January 13, 2011, 15:59

Hi, post your case in a .tgz (if it isn't large)...

Regards

ang_dipl_ing_fd · January 13, 2011, 16:16

Hi, monti. may be you have to set initialField to (0 0 0) will help. that's my problem. i simulate a laminar, steadyState flow over a cylinder (2D) with simpleFoam. if i set initialField for U to (0 0 0) everything ok. but if i use potentialFoam for initializing or even only set initialField to the inlet value everthing going worse. maybe someone can explain this phenomenon

monti · January 17, 2011, 04:39

Thanks for your response! I got some help from a forum member meanwhile ... thanks to Martin!

My case is running now, but it still needs some improvement. I already know what the next necessary steps are. If everything works fine, I will post my problems and the solution for other users. But first I have to understand exactly what I am doing ;-)

Regards

Mark

January 5, 2011, 12:31	laminar steady state using simpleFoam	#1
monti New Member Mark Join Date: Dec 2010 Posts: 9 Rep Power: 15	Hello, I want to run a simulation of a laminar waterflow in a channel using simpleFoam, but I get weird results. Here is what I have done: Changing file RASProperties and set RASmodell to laminar, turned off turbulence and printcoeffs. Changed nu in transportproperties to 1e-06 for water. Setting the boundaryconditions in 0/U to 0.5 m/s for the inlet, in 0/p boundarycondition for the outlet = 0. I set the endtime in controlDict to 10 seconds (why do I have to set an endtime anyway, it is not transient?). I get as a result a velocity of 3000. Has anybody an idea what I do wrong? Bye Mark

January 13, 2011, 15:59		#5
santiagomarquezd Senior Member Santiago Marquez Damian Join Date: Aug 2009 Location: Santa Fe, Santa Fe, Argentina Posts: 452 Rep Power: 24	Hi, post your case in a .tgz (if it isn't large)... Regards __________________ Santiago MÁRQUEZ DAMIÁN, Ph.D. Research Scientist Research Center for Computational Methods (CIMEC) - CONICET/UNL Tel: 54-342-4511594 Int. 7032 Colectora Ruta Nac. 168 / Paraje El Pozo (3000) Santa Fe - Argentina. http://www.cimec.org.ar

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January 5, 2011, 12:51		#2
monti New Member Mark Join Date: Dec 2010 Posts: 9 Rep Power: 15	Please forget everything so far! Endtime is used for iterations, setting it to a higher number everything works fine all of a sudden Bye Mark

January 6, 2011, 12:19		#3
monti New Member Mark Join Date: Dec 2010 Posts: 9 Rep Power: 15	I stuck! I thought I found the mistake, but I didn't. My results are still way too high, and I have no idea what to do. Can someone help me? I simply want to simulate a steady state laminar flow in a channel. Bye Mark

January 13, 2011, 14:09		#4
monti New Member Mark Join Date: Dec 2010 Posts: 9 Rep Power: 15	Who has used simpleFoam to simulate a steady state waterflow in a channel? I really need some help. Bye Mark

January 13, 2011, 16:16		#6
ang_dipl_ing_fd New Member Fatih Join Date: Sep 2010 Location: Hamburg Posts: 12 Rep Power: 16	Hi, monti. may be you have to set initialField to (0 0 0) will help. that's my problem. i simulate a laminar, steadyState flow over a cylinder (2D) with simpleFoam. if i set initialField for U to (0 0 0) everything ok. but if i use potentialFoam for initializing or even only set initialField to the inlet value everthing going worse. maybe someone can explain this phenomenon

January 17, 2011, 04:39		#7
monti New Member Mark Join Date: Dec 2010 Posts: 9 Rep Power: 15	Thanks for your response! I got some help from a forum member meanwhile ... thanks to Martin! My case is running now, but it still needs some improvement. I already know what the next necessary steps are. If everything works fine, I will post my problems and the solution for other users. But first I have to understand exactly what I am doing ;-) Regards Mark