### A Computational Strategy for Fluid-Structure Interaction Combining Immersed Domains and a Body-Fitted Approach

#### Abstract

There are many alternatives for treating the problem of a solid moving completely inside a ﬂuid. One of them is using the ﬂuid equations strictly in the space occupied by the ﬂuid, and adjusting the mesh in each temporal step. If the displacements are limited a node-movement strategy without topology changes may be used to keep low the computational costs. On the other hand, for large displacements and distortion of the computational domain (as usual when modeling cardiac valves), a full remeshing may be needed. Another approach to the problem is using immersed domains: in this case the ﬂuid mesh is ﬁxed and the solid imposes boundary conditions on the ﬂuid through Lagrange multipliers. In this work we present a hybrid approach: we use a single mesh for the ﬂuid, containing the solid, without remeshing. However, we allow the movement of its nodes to adjust to the solid boundaries. In this manner, we avoid the high cost of the remeshing step, while reducing the interpolation errors produced by elements that contain partially portions of the solid. Hence, the strategy is such that the body is always ﬁtted by the same mesh. The main difﬁculty of this approach is the generation of a valid mesh efﬁciently (without largely distorted elements), in transferring information between solid and ﬂuid meshes, and in the interpolations needed when re-adjusting. We have obtained some preliminary results working with a parallel Navier-Stokes solver, using geometric searching techniques that allow us to keep bounded the computational costs involved.

#### Full Text:

PDF

Güemes 3450

S3000GLN Santa Fe, Argentina

Phone: 54-342-4511594 / 4511595 Int. 1006

Fax: 54-342-4511169

E-mail: amca(at)santafe-conicet.gov.ar

**Asociación Argentina de Mecánica Computacional**Güemes 3450

S3000GLN Santa Fe, Argentina

Phone: 54-342-4511594 / 4511595 Int. 1006

Fax: 54-342-4511169

E-mail: amca(at)santafe-conicet.gov.ar

**ISSN 2591-3522**