|
[Sponsors] |
October 15, 2009, 18:13 |
Variable non-dimensional CFX
|
#1 |
New Member
Juan Lorenzo
Join Date: Jul 2009
Posts: 19
Rep Power: 17 |
I want to compare the results obtained in the CFX with another study but in this, they standardized the continuity and the Navier-Stokes equations it is possible to make non-diemnsional the equations in the CFX???
I understand that using one cell I can work the equations that I create I pleasure. what I want to know if the variables of the program (the continuity and the Navier-Stokes equations) can be standardized (non-adimensional) and since it becomes? if the answer is negative as I compare a study of simulation in CFX with another non-dimensional? |
|
October 15, 2009, 19:41 |
|
#2 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,872
Rep Power: 144 |
CFX is a dimensional solver. As long as you give it a consistent set of input units to work in then it is fine. You can define a unit system which is non-dimensional if you like.
Obviously you can compare a dimensional and non-dimensional solution. The non-dimensional result can be made dimensional by assuming a length, time and any other necessary scales and scaling the results to give a dimensional result. Alternately you can non-dimensionalise the CFX result. Either is fine. |
|
October 15, 2009, 23:18 |
|
#3 |
New Member
Juan Lorenzo
Join Date: Jul 2009
Posts: 19
Rep Power: 17 |
As I can non-dimensionalise the cfx result? I must establish to unit non-dimensional system which is before the simulation or after finished the simulation I can pass non-dimensionale the result?
|
|
October 18, 2009, 08:07 |
|
#4 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,872
Rep Power: 144 |
No, you can use the same non-dimensional system (eg U*=U/Uref where U* is the non dimensional velocity, U is the dimensional velcoity and Uref is the reference velocity) used to define to define the non-dimensional system in the first place to the CFX results.
|
|
October 18, 2009, 11:50 |
|
#5 | |
New Member
Juan Lorenzo
Join Date: Jul 2009
Posts: 19
Rep Power: 17 |
thanks Glenn... understand.
Now, already like establishing my non-dimensional system, but like I can cause that the CFX recognizes my non-dimensional variables to me. I explain myself: Quote:
Velocity u (non-dimensional) = Velocity u/Free Stream. Velocity u = Velocity that calculates the CFX Free Stream = Velocity of reference (I define) Q: Since I do so that the CFX works with my new variable (non-dimensional Velocity or) instead of velocity u? reading HELP CFX consegui this: (Example) EXPRESSIONS: Re = 4.29E6 [] Bel = 60 [m s^-1] L=1.044 [m] Visc=areaAve (density) @in*Vel*L/Re PROPERTIES: Option = Ideal Gas Molar Mass = 2.896E1 [kg kmol^-1] Dynamic Viscosity = Visc Specific Heat Capacity = 1.E3 [J kg^-1 K^-1] Thermal Conductivity = 2.52E-2 [W m^-1 K^-1] In theory it could make this but parameters like the Velocity u, v, w or distance x, y, z or density where not to look for them to change them by my expressions non-dimensional. I would want to settle down this non-dimensional system this way: Velocity u (non-dimensional) = Velocity u/Free Stream. Velocity v (non-dimensional) = Velocity v/Free Stream. Velocity w (non-dimensional) = Velocity w/Free Stream. X (non-dimensional) = X/Diam. Y (non-dimensional) = Y/Diam. Z (non-dimensional) = Z/Diam. t (non-dimensional) = (t*Free Stream) /Diam. same question, since I do so that the CFX works with my new variables and not with which it has by defect? excuses by my English… are very bad |
||
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Assign new variable in CFX Post | Ben | CFX | 1 | August 25, 2008 15:59 |
error in COMSOL:'ERROR:6164 Duplicate Variable' | bhushas | COMSOL | 1 | May 30, 2008 05:35 |
Env variable not set | gruber2 | OpenFOAM Installation | 5 | December 30, 2005 05:27 |
Solving Additional Variable in CFX? | Tuks | CFX | 6 | November 18, 2005 12:40 |
Replace periodic by inlet-outlet pair | lego | CFX | 3 | November 5, 2002 21:09 |