[nthiers]

Hi arslan, hace you tried defining dt field and use setField utility to start dt field with different values for your two regions.

[Arslan Arshad]

no i dont think so

[Arslan Arshad]

by the way how to do it.... i am new to openfoam

[nthiers]

Take a look at tutorial/multiphase/interfoam/system/setFieldsDict
There is used to initialize alpha field, but for your case just change alpha for dT and the boxToCell parameters to fit with your regions like this

Lets said that for the left region you need dt=0.1 and for the right dt=0.3

First set default value dt=0.1
Then in the boxToCell put the coordinates of the right region and inside put dt=0.3

Then use:
setField
yourSolver

[Arslan Arshad]

my geometry is 3d
left region (0.5x0.5x0.5) m
same is the dimension of right region
what is meant by boxToCell and how
what should be the coordinates.......please can you elaborate with example?

[Arslan Arshad]

and is there any need to change the DT in "transportproperties"


and is there any need of making "DT" named file as "T" in folder named "0"

[nthiers]

First of all you have to change the dt propertie to a volScalarField like mostafa said before.

Then you have to add the dt and T files to your 0 folder

(this was explained in a tutorial called "add temperature to icofoam" take a look on it, will be very helpful)

For the boxToCell utility, I have never used before soy I don't know exactly how to put the coordinates, for that you should search for your own, there is a interfoam tutorial on internet where there explain how to set it.

Sorry I can't help more with that

[Arslan Arshad]

i figured it out

boxToCell

(Min. Boundary coordinates) (Max. Boundary Coordinates);


you have to put minimum boundary coordinates and for maximum
that can be known by analysing your volume in software you are using for making geometry (in my case it is gambit)

thanks for the reply
will tell you about the solver after compiling it

[Arslan Arshad]

is there any need for "DT" in folder "0"?

if yes then what should be the boundary conditions?

[nthiers]

Yes it's necessary but how you arn't solving any transport equation for dt you don't need any boundary conditions but anyway the solver may ask you for them, in that case set any boundary condition fo dt like zerogradient

[Arslan Arshad]

i tried the solver but it gives the same value of "DT" over both regoins....

any suggenstions?

[nthiers]

can you show me yoru solver, your createFields.h, a schemes of your 0 folder and your setFieldsDict please

[Arslan Arshad]

thank you for the help but i sorted it out

you have to rename your file "DT.org" instead of "DT"

and then in terminal go to the address of the solver folder
and type
"cp -r 0/DT.org 0/DT"

this will make the DT file. in the "0 folder"

then type the command "setFields".


you are all set to go......

[nthiers]

thats right, let me know about your results.

[Arslan Arshad]

it shows infinity when i put the condition on the right side of domain (type zeroGradient)

but gives the solution when i give the boundary condition (type fixedValue) on the right face.

and i want the solver to calculate the value at the right face.....where am i wrong?


THANKS in advance

[nthiers]

Arslan sorry for the delay, am also doing some test with a problem like that and i figure that when use
div(phi,T) Gauss linear;

in the system/fvSchemes the T field diverges, but when use
div(phi,T) Gauss vanLeer;

it works fine in mi case, try it and let me know if it works

[ancolli]

Did u manage to solve the problem?
Can you post all the code?
Thanks in advance