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  several  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 format 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 filename.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 filename.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)