An improved direct-forcing immersed-boundary method for finite difference applications

A modified immersed-boundary method is developed using the direct-forcing concept. An improved bilinear interpolation/extrapolation algorithm is implemented for more accurate boundary forcing expressions and easier implementation. Detailed discussions of the method are presented on the stability, velocity interpolation on the immersed boundary, directforcing extrapolation to the grid points, resolution of the immersed b undary points, and internal treatment. The method can achieve second-order accurate solutions. The method is then applied to a finite-difference scheme to compute flow over a stationary cylinder, an oscillating cylinder, and a stationary sphere. The accuracy of the computational results is verified using numerous computational and experimental results in the literature. 2006 Elsevier Inc. All rights reserved. AMS: 65C20; 76D05; 76M20