- **CFX**
(*http://www.cfd-online.com/Forums/cfx/*)

- - **Negative pressure in 2D problem
**
(*http://www.cfd-online.com/Forums/cfx/25233-negative-pressure-2d-problem.html*)

Negative pressure in 2D problem
Hello world,
I tried to study the pression lost in a valve. To simplify, I tried to work in a 2D problem. You can see my model here : http://img101.imageshack.us/img101/1...opimagemi4.png My parameters are : - Air at 25°C - Steady state - Inlet = Pressure at 2200Pa - Outlet = Mass air flow at 0.0009 kg/s - Symetry on both side In the result, pressure on outlet is around -100000Pa !!! When I tryed on an 3D model, with same parameters, the result are Ok. Do you have any idea of this problem on 2D ? Thanks a lot for your help Micgre |

Re: Negative pressure in 2D problem
Hi,
Did you scale the mass flow rate to reflect the smaller area of the 2D model? For example, if you are modelling a channel 1 metre wide using a 2D flow with a 1mm wide slice, you will need to reduce the mass flow rates by a factor of 1000. Glenn Horrocks |

Re: Negative pressure in 2D problem
I already done this ratio :( I don't understand why this flow rate delta can create negative pressure ?
Thanks for your help. |

Re: Negative pressure in 2D problem
I think my problem is from symetry because when I work with my 3D model and cut an half, I've got negative pressure...
But I don't understand why... |

All times are GMT -4. The time now is 01:16. |