A variational projection scheme for nonmatching surface-to-line coupling between 3D flexible multibody system and incompressible turbulent flow. (30th March 2018)

• Record Type: Journal Article
• Authors: Gurugubelli, P.S.; Ghoshal, R.; Joshi, V.; Jaiman, R.K.
• Is Part Of: Computers & fluids. Volume 165(2018)
• Page Start: 160
• Page End: 172
• Publication Date: 2018-03-30
• Subjects: 3D flexible multibody -- Fluid-structure interaction -- Partitioned iterative -- Surface-to-line coupling -- Nonmatching meshes -- Offshore structures; Fluid dynamics -- Data processing -- Periodicals; 532.050285
• DOI: 10.1016/j.compfluid.2018.01.016
• Languages: English
• ISSNs: 0045-7930

Abstract

Highlights: New variational surface-to-line projection for 3D flow and flexible multibody interaction. Coupling of the variational projection scheme with NIFC scheme. Development of hybrid RANS/LES modeling for high Reynolds number. Validation of coupled framework for a long flexible marine riser. Application of the method for coupled problems in offshore/ocean engineering. Abstract: This paper is concerned with the partitioned iterative formulation to simulate the fluid-structure interaction of a nonlinear multibody system in an incompressible turbulent flow. The proposed formulation relies on a three-dimensional (3D) incompressible turbulent flow solver, a nonlinear monolithic elastic structural solver for constrained flexible multibody system and the nonlinear iterative force correction scheme for coupling of the turbulent fluid-flexible multibody system with nonmatching interface meshes. While the fluid equations are discretized using a stabilized Petrov–Galerkin formulation in space and the generalized- α updates in time, the multibody system utilizes a discontinuous space-time Galerkin finite element method. We address two key challenges in the present formulation. Firstly, the coupling of the incompressible turbulent flow with a system of nonlinear elastic bodies described in a co-rotated frame. Secondly, the projection of the tractions and displacements across the nonmatching 3D fluid surface elements and the one-dimensional line elements for the flexible multibody system in a conservative manner. Through the nonlinear iterative correction and the conservative projection, the developed fluid-flexible multibody interaction solver is stable for problems involving strong inertial effects between the fluid-flexible multibody system and the coupled interactions among each multibody component. The accuracy of the proposed coupled finite element framework is validated against the available experimental data for a long flexible cylinder undergoing vortex-induced vibration in a uniform current flow condition. Finally, a practical application of the proposed framework is demonstrated by simulating the flow-induced vibration of a realistic offshore floating platform connected to a long riser and an elastic mooring system.