GPIV_VORSTRA(1) 					      General Commands Manual						   GPIV_VORSTRA(1)

NAME

       gpiv_vorstra - Calculates the differential quantities vorticity, shear strain and normal strain from PIV data.

SYNOPSIS

       gpiv_vorstra [-d N] [-h | --help] [-n | -o | -s] [--no_g ] [-p | --print] [-g | --g] [-v | --version] [filename] < stdin > stdout

DESCRIPTION

       gpiv_vorstra  calculates the differential quantities like vorticity, shear strain and normal strain from PIV data. You can choose from sev-
       eral differential schemes: central differentiation, least squares, Richardson extrapolation and circulation method. Circulation method only
       allows one to calculate vorticity, but no strain. The output can be generated as ASCII data containing four columns or as GNUPlot Data for-
       mat that allows one to view/print the data as contour plots.

       The configuration parameters (containing the POST key) may be overruled by the command line options, as explained below.

Options
       -d N   Differential type to be used: central difference (N=0), least squares (N=1),  Richardson	interpolation  (N=2),  circulation  method
	      (N=3)

       -h | --help
	      On-line help

       -n     Calculate  normal  strain  of the PIV data. As an alternative the program may be called by its nickname gpiv_nstrain. In combination
	      with filename the output will be written to filename.nstr.

       -o     Calculate vorticity of the PIV data. As an alternative the program may be called by its nickname	gpiv_vorty.  In  combination  with
	      filename the output will be written to filename.vor.

       -p | --print
	      Print  parameters,  command  line  options  and eventually used input and output filenames to stdout. The output is identic of file-
	      name.par, in case filename is used.

       -s     Calculate shear strain of the PIV data. As an alternative the program may be called by its nickname  sstrain.  In  combination  with
	      filename the output will be written to filename.sstr.

       -g     Show contour plot of the output with gnuplot.

       --no_g Suppresses to show contour plot of the output with gnuplot.

       -v | --version
	      Print version information on standard output, then exit successfully.

       filename
	      Input  PIV data file. Overrides stdin and stdout. The output will be written to filename.vor with -o, filename.nstr with -n or file-
	      name.sstr with -s.  Parameters are stored in filename.par and may be used for future use by including them in ./gpivrc.

SEE ALSO

       gpivtools

AUTHOR

       Gerber Van der Graaf

								  8 November 2006						   GPIV_VORSTRA(1)