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How to compile a new utility

Hi,
I am new openfoam user and I am not good at programming :eek:. I intend to find grad of a scalar variable which is a solution of my computation :confused:. Initially I used a function "gradient of unstructured variable" from paraFoam but it is giving me some error.So I am trying to make my own utility to calculate gradient of scalar quantity.Now,I guess if I make a new utility i would have to compile it with my solver and for that I am following instructions given in Userguide.I mentioned utilityFunctionObjects lib name in solver/Make/options and then used wmake command from inside solver dir. I guess it goes on well and ultimately yields a messege that solver is uptodate,but when i use the new utility command name from inside case directory it says command is not found.Can anyone please tell me what exact steps I should take to compile my newly defined utility file with the intended solver.
Thanks and regards,
rudy.

Rudy,

Some searching through the OF forums will turn up a number of links to courses, tutorials, etc that cover programming and customizing applications. Here's a link that may be helpful: http://www.openfoamworkshop.org/2009...ngTutorial.pdf. A recent thread has an excellent list of links. http://www.cfd-online.com/Forums/ope...thingelse.html. Learning Foam is challenging, but it's worth the effort.
Good luck, Alan

Quote:

Originally Posted by rudy (Post 239814)

Take a look at laplacianFoam. In write.H gradients of the temperature are computed and stored. The procedure is general.

To sum it up

Compute the gradient vector and store it in a volVectorField as in

Code:

volVectorField gradT = fvc::grad(T);

You can decompose the gradient in its components too, storing them in separate files. For example for the x component, which will be stored in a file called "gradTx", you can use:

Code:

volScalarField gradTx

        (

            IOobject

            (

                "gradTx",

                runTime.timeName(),

                mesh,

                IOobject::NO_READ,

                IOobject::AUTO_WRITE

            ),

            gradT.component(vector::X)

        );

Note that

the instructions are enclosed in an if whose condition is runTime.outputTime(), which means that fields will be written when a set of data will be automatically saved by the solver
the gradient components are stored, but the gradient vector field is not stored. To do that simply add th following line after the definition of gradT:

Code:

gradT.write();

You can edit your code adding similar lines for the variable of your interest, and then rebuild the application with

Code:

wmake

in the directory containing the source code.

I hope this help.

Best,
Alberto

P.S. Simple answers to simple questions! Sometime a "search for it" simply does not work, especially for new users. :D

Thanks a lot to both of u, I did develop my own utility to find gradient using ur instructions and it's working now...
regards,
rudy

gradT.write(); returns a zeroGradient field for patches. But the field is non-zero in component files like gradTx. Why?