CFD Online Logo CFD Online URL
Home > Forums > OpenFOAM Programming & Development

temperature / enthalpy fields depending on type of fvPatchField

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

LinkBack Thread Tools Display Modes
Old   June 28, 2010, 07:10
Default temperature / enthalpy fields depending on type of fvPatchField
New Member
Join Date: Mar 2010
Posts: 27
Rep Power: 7
astein is on a distinguished road
Dear Foamers,

I experienced the following issue:
I am writing a boundary condition, which can be used for writing pressure, temperature and velocity values. Since none of the available boundary conditions really fitted to what I want, I derived by new BC directly from the class "fvPatchField". While trying out some simulations, I figured out that an enthalpy field (internalField dimensions 0 2 -2 0 0 0 0) is created as a copy from the temperaturefield (internalField dimensions 0 0 0 1 0 0 0). The updateCoeffs() ob my customized boundary condition is called with these dimensions throughout the simulation, but not with a internalField with temperature dimensions.

Therefore I thought I had to write enthalpy values to this object of my fvPatchField. Nevertheless, writing values to this enthalpyfield did not change anything in the output of the simulations. The temperature values of the boundaryfield stayed on their initial values. Writing pressure and velocities worked out fine.

In a second step, I analyzed how the totalTemperature BC writes the temperature. Here, i recognized that no enthalpy field is created for this boundary condition.
After some further digging in the code, I found out that the boundary conditions are treated differently, if they are of the following types (or inheriting them): fixedValue, fixedGradient, zeroGradient, mixedFvPatchField. I changed my implementation to one which is inheriting mixedFvPatchField and now writing temperature values does work as well.

In there anybody out there who is willing to explain WHY the type of the boundary condition is important for the simulation? Why do self-made boundary conditions have to be derived from those base classes to be able to write temperature values?

Thanks a lot in advance!
astein is offline   Reply With Quote


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
Fluent msh and cyclic boundary cfdengineering OpenFOAM Other Meshers: ICEM, Star, Ansys, Pointwise, GridPro, Ansa, ... 48 January 25, 2013 04:28
Cyclic BC's: Possible face ordering problem? (Channel flow) sega OpenFOAM Native Meshers: blockMesh 3 September 28, 2010 12:46
buoyantSimpleRadiationFoam msarkar OpenFOAM 0 February 15, 2010 07:22
Using createPatch in place of couplePatches sripplinger OpenFOAM Mesh Utilities 8 November 13, 2009 08:14
Convective Heat Transfer - Heat Exchanger Mark CFX 6 November 15, 2004 16:55

All times are GMT -4. The time now is 09:24.