PHASTA/Probe points

Phasta is capable of outputting solution field variables such as velocity, pressure, eddy viscosity, and temperature (if applicable) at specified locations in the fluid domain.

Using Probe Points

To enable probe points, the file xyzts.dat and the folder varts/ must both be present in the n-procs_case directory that is being used by Phasta. The file xyzts.dat should contain a one line, space delineated header with the following numeric data (based of of the version in /users/mattb2/phasta-tocmake/...)

• number of probes
• frequency (i.e. the number of steps between sampling)
• tolerance (unused)
• iterate (unused)
• varcod (unused)

The lines following the header should contain x, y, z data specifying the location of the probe points. As an example, a valid xyzts.dat file for an incompressible run would look something like:

 4 1 1.0e-6 1 5
 0.2 -0.02 -0.01
 0.2 -0.02  0.01
 0.3 -0.02 -0.01
 0.3 -0.02  0.01

...although a header of 4 1 1 1 1 should be equally as valid.

For multiple cases which use the same probe locations, it is often convenient to keep xyzts.dat in a lower level directory and soft link to it. That is, the setup process becomes

 cd n-procs_case
 mkdir varts
 ln -s ../../xyzts.dat .

Note: in most versions of Phasta, the varts.*.sn files are created prior to the calculation of the first time step, but are actually written to after finishing the last time step. This means that if a run is interrupted (e.g. by not requesting enough time in a queue), no useful data will be generated.

Location in Phasta

In the compressible version of Phasta, xyzts.dat is read exclusively in

 phSolver/compressible/itrdrv.f.

To fix the problem where probe points are only written after the final time step, consider the following modifications to itrdrv.f:

• change

 read(626,*) ntspts, freq, tolpt, iterat, varcod

to

 read(626,*) ntspts, freq, tolpt, iterat, nbuff

to be consistent with previous naming conventions. From there

...eh NGC code and trunk are considerably different. I'll merge the changes sometime in the morning.