The preceding approach works well if the forcing point is associated
with only one solid node, as is true for forcing nodes shown in
the upper-right part of Fig. 2. On the other hand, if the forcing point is
associated with two solid nodes, then ambiguity occurs as indicated
in the figure. To remove this ambiguity, Liao et al. [19] proposed
utilizing simple linear interpolation between the diagonal node xA
and the node xB on the boundary, as shown in Fig. 2.
2.4. Complete solution procedure
The full numerical procedure for each time step of the proposed
method is summarized in the following pseudo-language algorithm.
Algorithm. (Fractional-step/direct forcing immersed-boundary
method) Suppose n time steps have been completed. To calculate
the solution at time level n þ 1 carry out the following steps.
1. Determine the immersed-boundary location at step n þ 1.
2. Identify fluid and solid points on Eulerian grid.
3. Establish locations of forcing points.
4. Predict velocity and temperature without forcing terms.
(a) Use Eq. (11) to determine bu.
(b) Use Eq. (12) to determine bT .
5. Compute forcing terms.