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cfx4.3 user February 14, 2003 10:00

users fortran USRBCS
hello all

I would like to read inlet temperature profile from a matrix file for a transient flow (the 1st column is time and the second is temperature) using the fortran routine USRBCS at user area 5. Is there any one who knows howto do it in fortran. I mean calling a file or array defination....

thanks a lot

cfx 4.3 user

Azeez March 3, 2003 06:11

Re: users fortran USRBCS
I am also trying to solve a similar problem. I want to fix my own temperature in the bounday condition at the start of every time step which is dependent on the reaction heat(flow with reaction) produced in the previous time step. the same applies to the pressure. if u managed to find a solution for ur problem can u please help me in solving this. thanks in advance. sincerely Azeez

Jeff March 5, 2003 19:02

Re: users fortran USRBCS
These are two slightly different problems:

CFX4.3 User ============ Open the file in USRINT and read the array of times and temperatures into arrays and store them in a common block. Then in USRBCS, you have access to the TIME variable. Compare this TIME variable to your time array and set the corresponding (or interpolated) inlet temperature on the boundary condition.

Azeez =========== Through the WORK array (see chapter 11 of the manual) you have access to the VAROLD stack. You can access all temperature and pressure values from the previous time step there. You can then use these values to set your current time step values.

NOTE: for both cases, make sure you set the BCSFLG so that the routine gets called for every iteration and timestep (this is a value of 3 I think). Usage of this flag is documented in the comments.

Cheers, Jeff

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