No abstract

The present work is devoted to simulation of fluid-structure interaction and flow-induced vibration problems by using a partitioned procedure. A finite element structure solver is coupled with a finite volume fluid solver. A coupling interface has been developed for grid interpolation and scheme coupling control. An alternative mesh motion to a classical ALE formulation is proposed for the fluid computation and the method is validated by means of a test-case involving a pipe conveying fluid.

As far as flow-induced vibrations are concerned, fluid structure interactions and fluid elastic effects are involved. They may be characterized by parameters like added mass, added damping and added stiffness describing fluid and flow effects on structure motion. From a numerical point of view, identifying these parameters requires numerical simulation of coupled fluid and structure problems. To perform such a multi-physics computation, several numerical methods can be considered involving either a partitioned or a monolithic fluid structure code coupling procedure. Monolithic process is a fully implicit method ensuring the energy conservation of the coupled system. However its implementation may be difficult when specific methods are required for both fluid and structure solvers. The partitioned procedure does not feature the same disadvantage because fluid and structure computations are staggered in time. However a specific attention must be paid to the energy conservation of the full coupled system and one must choose code coupling schemes in order to avoid or to reduce as much as possible numerical dissipation polluting the results. In the present paper, several techniques for fluid structure code coupling are compared. Several configurations are considered and numerical results are discussed in terms of added mass and damping for structures vibrating in fluid at rest. These results contribute to the validation of a full fluid structure code coupling procedure with many possible applications in the fields of fluid structure interactions and flow-induced vibrations.

In multi-physics numerical computations a good choice of code coupling schemes is required. Several methods are possible like: an explicit synchronous scheme an Euler implicit method and no interpolation on velocity pressure; an explicit asynchonous scheme using a Crank-Nicholson time integration scheme and interpolation on velocity and pressure; an implicit scheme using a fixed iterative method. In the present paper these different schemes are compared for application in fluid structure interaction field. In the first part numerical coupling schemes are presented. Then their capability to ensure energy conservation is discussed according to numerical results obtained in analytical test cases. Finally application of coupling process to fluid structure interaction problems is investigated and results are discussed in terms of added mass and damping induced by a fluid for a structure vibrating in fluid at rest.