Plotting data fields

Data fields in OnScale refer to snapshots of particular qualities at specific times in the model. The CALC command is used in OnScale as a means to specify secondary field variables and energy quantities to be computed and stored during execution. Secondary field variables are nodal and elemental quantities that the computational algorithm does not require to be stored during the computation. Secondary field variable require very little CPU time, but require large amounts of memory to store requested data.

A few examples will be presented showing some of the ways time histories can be plotted during execution, all examples were done by modifying the PZT Disk 2D example in our Examples section:

 calc
	pres acoustic 		/* Calculate acoustic pressure
	disp   			/* Calculate X and Y displacements
	max aprs none pmax      /* Calculate maximum pressure field
	max ydsp none ydmax     /* Calculate maximum pressure field
	end

displacement, pressure and acoustic pressure data has been requested via the CALC command.

These examples will show how to plot the requested data fields. These requested data fields can also be plotted wit time histories however for these particular example they will not be plotted, more information on plotting time histories can be found here. Some initial set up is required before using the GRPH command to plot the requested data.

prcs

symb #get { step } timestep        /* Extract calculated timesteps from PRCS command    
symb simtime = 40 / $freqint       /* Simulation time - 40 cycles / @ 1 MHz
symb nexec = $simtime / $step      /* Determine how many timesteps to run full model
symb nloops = 40                   /* Plotting snapsots during model execution
symb nexec2 = $nexec / $nloops

grph
     arrow off                     /* Turn off arrows 
     line off                      /* Turn off mesh lines
     set imag mpeg                 /* Set up image capture for movie file generation
     nvew 1                        /* Set up 1 plotting widows 
     end

proc plot save

exec $nexec2 

** INSERT GRPH COMMAND HERE ** 

end$ proc		/* End of Procedure Code

c Run model by calling 'plot' procedure 'nloops' times
proc plot $nloops

term	/* Pause model - Allow user to call procedure 'plot' from console window to run model for longer

The acoustic pressure in a model can be plotted using the following:

grph 
     plot aprs	        /* Plot calculated data array
     imag		/* Snapshot of Graphics window for Movie generation
     end

The scales of the plots are, by default, scaled from max to min but they can be modified using the “rang” option:

grph
     plot aprs rang -3.e3 3.e3       /* plot pressure with a scale limitation
     end

Notice how the scale of the plot has changed to the modified scale

Slices of fields may be plotted using the “plot” sub command in the following manner:

grph
     plot aprs i $i2        /* plot a slice of pressure along $i2
     end

The model used as an example is 2D but multiple slices or cross sections of a 3D model can be plotted using the PLOT subcommand in the following manner:

grph
     plot pres i 2 pres j 5 pres k 1

This will give 2D slices of pressure, all on the same plot, at i = 2, then j = 5 then k = 1.

These are very basic examples of how to use your data. For more help on the GRPH command or for more advanced subcommands that accompany GRPH please refer to OnScale help documentation that can be accessed via the help tab in the application's ribbon.