|
[Sponsors] |
July 8, 2002, 07:30 |
UDS source term units
|
#1 |
Guest
Posts: n/a
|
Hi to all,
which are the units of the source terms for user defined scalar in fluent? If I write a source term for a scalar, e.g. a concentration (kmol/m^3), using mass flow rate as the flux function, the solved equation should be eq. 9.2-3 on page 9-2 of Fluent6 UDF Manual. According to this equation the units should be kg*m^-3*s^-1*(scalar unit), i.e. for concentration, kg*kmol*m^-6*s^-1. Is that right? Should I multiply a source term whose units are kmol*m^-3*s^-1 by the density (or by something else) to fit the units used in Fluent? Is it the same for Fluent4, Fluent5 and Fluent6? Thanks a lot |
|
July 8, 2002, 16:29 |
Re: UDS source term units
|
#2 |
Guest
Posts: n/a
|
Source term is always defines as source per unit volume. What at the units of a UDS? You define this. So your source units are (UDS stuff)/m^3
|
|
July 12, 2002, 14:01 |
Re: UDS source term units
|
#3 |
Guest
Posts: n/a
|
Hi,
It's more convenient to define your scalar concentration per unit mass of mixture instead of per unit volume. Thus, your scalar should have the unit (kmol/kg), and the source term in the scalar transport equation should have the unit kmol/(m^3*s). In fact, since the convective flux in Fluent is a "mass flow rate", the scalar must be expressed per unit mass to get a correct convective transport. Of course, after you have solved your scalar equation, you can multiply your results by the density to get the concentration in (kmol/m^3) if you prefer to present your results using that unit. Regards, Ola Nordblom |
|
March 29, 2017, 08:08 |
|
#4 | |
Member
Rosario Arnau
Join Date: Feb 2017
Location: Spain
Posts: 57
Rep Power: 9 |
Quote:
How can I set the units od my UDS?? I thought that their units are always kg/m^3..... I need to define the units of my UDS to g/m^3 and kmol/m^3.... Thanks! |
||
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Problem of SOURCE term gradient in UDS | wind | Fluent UDF and Scheme Programming | 6 | December 1, 2022 15:21 |
[swak4Foam] swak4foam building problem | GGerber | OpenFOAM Community Contributions | 54 | April 24, 2015 17:02 |
DxFoam reader update | hjasak | OpenFOAM Post-Processing | 69 | April 24, 2008 02:24 |
DecomposePar links against liblamso0 with OpenMPI | jens_klostermann | OpenFOAM Bugs | 11 | June 28, 2007 18:51 |
UDF Source Term Units? | Brian | FLUENT | 1 | October 24, 2005 10:15 |