CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Running, Solving & CFD

Dimension Error not while adding heat source with Heat Equation

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   September 19, 2013, 10:29
Unhappy Dimension Error not while adding heat source with Heat Equation
  #1
Member
 
Himanshu Sharma
Join Date: Jul 2012
Posts: 85
Rep Power: 6
himanshu28 is on a distinguished road
Hi,

I am trying to add Energy source in the turbulent energy equation given below,
Code:
{
alphat = turbulence->nut()/Prt;
alphat.correctBoundaryConditions();

volScalarField alphaEff
("alphaEff",
turbulence->nu()/Pr + turbulence->nut()/Prt
);

    fvScalarMatrix TEqn
        (
            fvm::ddt(T)
            + fvm::div(phi, T)
            - fvm::laplacian(alphaEff, T)
            - q/Cp1
        );

   	TEqn.relax();
	
        TEqn.solve();
}
so if you check the dimension of the equation it is coming (kelvin/sec) , my source q is specified in terms of (j/sec) hence i divided it with the heat capacity Cp1(j/k) of my source and specified correct dimensions in the transport property as well >my solver is running properly if i remove this source term but when i am trying to run with this source term its giving me the following error.

Code:
Different dimensions for =
     dimensions : [0 2 -1 0 0 0 0] = [0 4 -3 0 0 0 0]


    From function dimensionSet::operator=(const dimensionSet&) const
    in file dimensionSet/dimensionSet.C at line 165.
i am not able to track this bug in the solver if somebody can help me on this i will be thankful

Regards
Himanshu
himanshu28 is offline   Reply With Quote

Old   September 20, 2013, 07:11
Default
  #2
Senior Member
 
Join Date: Aug 2013
Posts: 227
Rep Power: 6
Antimony is on a distinguished road
Hi,

Are you sure Cp1 is not the specific heat capacity? If it is specific heat capacity then the units would be J/(kg.K).

Also, isn't the unit of q W/m2?

Regards,

Antimony
Antimony is offline   Reply With Quote

Old   September 20, 2013, 07:18
Default
  #3
Member
 
Himanshu Sharma
Join Date: Jul 2012
Posts: 85
Rep Power: 6
himanshu28 is on a distinguished road
Quote:
Originally Posted by Antimony View Post
Hi,

Are you sure Cp1 is not the specific heat capacity? If it is specific heat capacity then the units would be J/(kg.K).

Also, isn't the unit of q W/m2?

Regards,

Antimony
i referred the following article http://www.idurun.com/?p=556 to fit turbulent energy in my case. if you see the right hand side of the equation the dimensions you will find as (K/sec) and to justify the dimension i used q in (j/sec) and Cp1 in terms of heat capacity not specific heat capacity. so q u can assume here is in Watt only.
himanshu28 is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Question about heat transfer coefficient setting for CFX Anna Tian CFX 1 June 16, 2013 06:28
build problem swak4Foam OF 2.2.0 mcathela OpenFOAM Installation 14 April 23, 2013 13:59
funkySetFields compilation error tayo OpenFOAM 39 December 3, 2012 06:18
OpenFOAM on MinGW crosscompiler hosted on Linux allenzhao OpenFOAM Installation 127 January 30, 2009 20:08
heat equation solution source code john Main CFD Forum 1 May 27, 2004 23:41


All times are GMT -4. The time now is 13:58.