bht_round_rectangle page

Biohydrodynamics Toolbox    

bht_round_rectangle

Define a rectangle-shaped boundary.

Syntax

y = bht_round_rectangle(t,der,settings)

Description

This function defines a rectangle-shaped boundary as a parameterized closed line over [0,2*pi[. The input variable t (the parameter) is a vector with all of its elements within [0,2*pi[. The function returns, depending on the flag der:

• der = 0: the points' coordinates corresponding to the parameter t.
• der = 1: the coordinates of the tangent vectors (the first derivative of the parameterization).
• der = 2: the second derivative of the parameterization.

The input variable settings is a row vector with six elements: 

• The rectangle is centered at the point of coordinates settings(1:2).
•  Its width is 2*settings(3) and its height is 2*settings(4).
•  Since boundaries have to be twice continuously differentiable lines within BhT, the rectangle's corners are smoothed. Thus, settings(5) has to be within ]0,1] and is the smoothing parameter.
• settings(6) is a flag (-1 or 1) for the orientation of the boundary: 1 means that the boundary has a counterclockwise orientation and -1 a clockwise orientation.

See also:

Fluid's boundaries

bht_boundary_check

2008 - A. Munnier and B. Pincon (Insitut Elie Cartan and INRIA Lorraine, Projet CORIDA, Nancy, France).