partice

NAME

particle

SYNOPSIS

         particle [-d densxy] [-P partfile] [-x] [-y] [-X densx] [-Y densy]

DEFAULTS

           -d 2 -X 2 -Y 2

DESCRIPTION

particle specifies fluid marker properties. The markers are used in the IBIS visualization routines to help understand fluid movement. particle interpretes the optional statements

• -d densx - Initial number of pixels between fluid marker particles in both directions.
• -P partfile - name of a datafile with marker particles.
• -x - A line of new particles is created in the x direction as marker particles leave the domain.
• -X densx - Initial number of pixels between fluid marker particles in the x direction.
• -y - A line of new particles is created in the y direction as marker particles leave the domain.
• -Y densx - Initial number of pixels between fluid marker particles in the y direction.

The marker-density specifies the initial distance, in pixels, between fluid markers. These markers do not exert forces on the fluid, just flow in it and help the visualization of the flow.

If -x and/or -y are ommitted from the specification of particle, the numerical codes will periodicaly map fluid marker particles from a downstream edge to an upstream edge of the simulation. For example, if a particle leaves the specified domain traveling east at the point (x_max,y), that particle will immediately reappear at the point (x_min,y).

If -x and/or -y is contained in the specification of particle, the numerical codes will inject new particles into the simulation along the specified upstream edge (x for -x and y for -y). The new particles are uniformly spaced along the upstream edge when they are injected. The injection frequency is chosen so that the number of particles in the domain remains roughly constant in time.

SEE ALSO

visual