In some instances, you may want to modify the settings for a material property in CFD-ACE-GUI without stopping the current CFD-ACE-SOLVER run.  To do this, you can write a user subroutine to read in the new properties while the simulation is running.  In this user tip, the UPOROUS user subroutine is used as an example.

In this example, we will modify the porosity for a particular volume condition where we have specified the UPOROUS option.  In this routine, we will look for a file called "LookF1", which is just an indicator that new porosity settings should be read.  If the "LookF1" file is present, the routine will read another file called "F1", which contains the new porosity settings to be applied.  After reading the new porosity settings, the "LookF1" file is deleted to prevent further reading of the porosity settings.  Initially, the "LookF1" and "F1" files should be present to properly initialize the porosity of the material.  Figure 1 is a flow chart for the subroutine.

Figure 1.  Flowchart for modifying material properties during a simulation 

Any material property such as viscosity, specific heat, etc. can be modified using this technique.   Boundary conditions, such as flow velocity or temperature, could also be modified using a user subroutine and reading an input file.  

If you would like to download the UPOROUS user subroutine used for this tip, please click here.

Regards,
Hans-Wilfried Mindt
Applications Engineer - Germany