A modified ALE method for fluid flows around bodies moving in close proximity

•A modified ALE method for fluid flows around bodies moving in close proximity is developed and presented.•It is developed for 2D moving objects in close proximity of a symmetry plane.•Spurious oscillations at higher Reynolds numbers for flapping wings are studied.•The modified ALE method shows a reduction in spurious oscillations at higher Re.•The modified ALE method has a lower mesh requirement than a typical IBM.

A modified ALE method combining a body conforming mesh and a topology changing algorithm is developed to simulate unsteady symmetric fluid problems with bodies in close proximity. By using this method, the advantages of the original ALE method are used, while the disadvantages are reduced or eliminated. A mesh topology changing algorithm is used to create a computational domain boundary, while still having a smoothly deforming mesh in the remaining part of the mesh. It is shown that at higher Reynolds numbers the newly developed method performs better in terms of spurious oscillations than an immersed boundary method (IBM).