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.

AUTHOR