circle

NAME

circle

SYNOPSIS

          circle x0 y0 r [-optional link arguments]

DESCRIPTION

circle creates a circular entity of immersed boundary points. circle requires three arguments.

• x0 - x coordinate of the circle center
• y0 - y coordinate of the circle center
• r - the radius of the circle

circle allows for optional link arguments by interpreting the following options.

• -A name - indicates this entity is active and provides a name
• -a angle - resting angle at the IB points
• -b bend - bending stiffness at the IB points (default=40000)
• -d distance - initial distance between IB points (default=0.5)
• -N name - provides a name for the entity
• -n number - number of IB points around the circle
• -s stiff - inter-IB-point spring stiffness (default=40000)
• -t tether - tether spring stiffness (default=0)

The default resting length is determined so the points are no more than a distance of h/2 apart. The default resting angle is determined so that the circle remains a circle if there is no fluid flow. The tether points are located at the initial IB point positions.

SEE ALSO

line, polygon, wheel

EXAMPLE

          circle 1.0 1.25 0.5 -b 10000

Forms a circle centered at (1,1.25) with a radius of 0.5 and increases the bending stiffness to 10000. The circumference of the circle is $\pi$, and the resting length is not specified so the number of immersed boundary points set by IBIS is $\lceil 2\pi/h \rceil$ and they are equally spaced on the circle.