Sharp interface Cartesian grid method I: An easily implemented technique for 3D moving boundary computations

A Cartesian grid method is developed for the simulation of incompressible flows around stationary and moving three-dimensional immersed boundaries. The embedded boundaries are represented using level-sets and treated in a sharp manner without the use of source terms to represent boundary effects. The narrow-band distance function field in the level-set boundary representation facilitates implementation of the finite-difference flow solver. The resulting algorithm is implemented in a straightforward manner in three-dimensions and retains global second-order accuracy. The accuracy of the finite-difference scheme is established and shown to be comparable to finite-volume schemes that are considerably more difficult to implement. Moving boundaries are handled naturally. The pressure solver is accelerated using an algebraic multigrid technique adapted to be effective in the presence of moving embedded boundaries. Benchmarking of the method is performed against available numerical as well as experimental results.