Single Time
Step in IB Method

•Given **X**ni evaluate force **F**ni on boundary marker i due to other material points for all i=1, Nparticles in
material (Lagrangian).

•Spread **F**ni to
Eulerian grid using Delta-function [for each layer if multiple layers]. Gives **f**n, the force
on the fluid due to the
boundary/material points.

•Solve forced Navier-Stokes equations to update velocity field to time level n+1, thus giving **u**n+1

•Gather Eulerian velocity field values surrounding a
given particle using
Delta-function. Gives **U**n+1i .

•Use No-Slip condition to push boundary points to new values, so **X**n+1i emerges.