Numerical modeling of fluid-structure interaction

Abstract

A coupled fluid-structure interaction (FSI) analysis represents a challenging task from engineering point of view. Except a few special FSI problems, the only way to perform interaction analysis is the use of experimental or numerical methods. This thesis deals with the numerical modeling of fluid-structure interaction adopting so-called staggered approach, which solves both phases separately and employs information exchange on the interface to enforce compatibility. The main objectives of this work are the formulation and development of a numerical model for the analysis of FSI problems, its implementation and validation on benchmark examples. The fluid flow is modeled by the finite element method using Lagrangian formulation of governing equations. This approach is based on the particle finite element method. The computational domain is discretized by abstract particles, for which the incompressible Navier-Stokes equations are solved in each time step, resulting in velocities and pressure values. Lagrangian approach requires frequent remeshing to avoid distortion of background elements defined by topology of particles. For these purposes, a mesh generator based on the Delaunay triangulation is implemented. The boundary of the domain is recovered by the Alpha Shape concept. The developed model of fluid flow is validated on the examples of the water column collapse and free oscillation of a liquid in a container. The coupling of the fluid and structural problems is enabled by the implementation of iterative solver using the Dirichlet-Neumann approach based on the exchange of velocity and pressure values on the interface. Capabilities of the pilot implementation are illustrated on an example of clamped elastic gate of a fluid container.

A coupled fluid-structure interaction (FSI) analysis represents a challenging task from engineering point of view. Except a few special FSI problems, the only way to perform interaction analysis is the use of experimental or numerical methods. This thesis deals with the numerical modeling of fluid-structure interaction adopting so-called staggered approach, which solves both phases separately and employs information exchange on the interface to enforce compatibility. The main objectives of this work are the formulation and development of a numerical model for the analysis of FSI problems, its implementation and validation on benchmark examples. The fluid flow is modeled by the finite element method using Lagrangian formulation of governing equations. This approach is based on the particle finite element method. The computational domain is discretized by abstract particles, for which the incompressible Navier-Stokes equations are solved in each time step, resulting in velocities and pressure values. Lagrangian approach requires frequent remeshing to avoid distortion of background elements defined by topology of particles. For these purposes, a mesh generator based on the Delaunay triangulation is implemented. The boundary of the domain is recovered by the Alpha Shape concept. The developed model of fluid flow is validated on the examples of the water column collapse and free oscillation of a liquid in a container. The coupling of the fluid and structural problems is enabled by the implementation of iterative solver using the Dirichlet-Neumann approach based on the exchange of velocity and pressure values on the interface. Capabilities of the pilot implementation are illustrated on an example of clamped elastic gate of a fluid container.