Solved: Re: Problem with Resistance under CFD 2014

Anonymous · ‎08-30-2013

Hello community,

I have a problem with Resistance under CFD 2014.

I have CFD Study which was created, simulated and post-processed with CFD2013.

Now i use the support File for import in CFD 2014, because i need the geometry in 2014.

But it do not work. 2014 have any problems with the Resistance. Any cases divergence...

i pick for the resistance a konstant value of 20 in the main flow. The secondary flow is locked by me with a value of 1e+6 and 1e+7 (like in the tutorial and handbook).

I think, the solver have problems with the high resistance constant value.

Do you have any ideas?

Greetings Frank

OmkarJ · ‎08-30-2013

Probably, your turbulence numerics is not relaxed approproately? How about decreasing the under relaxation factors? Also, you may want to make sure Automatic Intelligent Control is enabled, it takes care of timescales through out the domain. You can only judge the performance of resistance after you are sure all the other factors are taken care of.

OJ

marco.mueller · ‎09-02-2013

Hi Frank,

try the flag "no_difu_tensors 1", which resets the resistance model to v2013.

Marco

Dipl.-Ing. (FH) Marco Müller
Application Engineer Digital Simulation
Mensch und Maschine Deutschland GmbH
www.mum.de/cfd

ozaha · ‎10-10-2013

Had similar problem to Frank's. Used the flag option Marco mentioned. It worked like a charm.

Thanks

Oz

tobias.schrammWK58Y · ‎10-11-2022

I built a model with a resistance layer in the air pass and encounter different volume flows in different heights --> see image description. Any idea anyone? I would expect to have similar volume flows in every layer.

top (air inlet) --> area volume flow (3687 m³/h) way off compared to higher than input (792 m³/h)speed vectors are uniformbottom (air outlet) --> area volume flow (812 m³/h) nearly input (792 m³/h)near top --> area volume flow (1972 m³/h) much much higher than input (792 m³/h)