Analysis of several subcycling schemes in partitioned simulations of a strongly coupled fluid‐structure interaction. (18th October 2018)

• Record Type: Journal Article
• Authors: De Moerloose, Laurent; Taelman, Liesbeth; Segers, Patrick; Vierendeels, Jan; Degroote, Joris
• Is Part Of: International journal for numerical methods in fluids. Volume 89:Number 6(2019)
• Page Start: 181
• Page End: 195
• Publication Date: 2018-10-18
• Subjects: arbitrary Lagrangian‐Eulerian -- implicit fluid‐structure interaction -- partial differential equations -- Reynolds‐averaged Navier‐Stokes -- stability; Fluid dynamics -- Mathematics -- Periodicals; 532
• DOI: 10.1002/fld.4688
• Languages: English
• ISSNs: 0271-2091

Abstract

Summary: Fluid‐structure interaction (FSI) simulations are used extensively to calculate the vibration of structures subjected to an internal or external flow. In the case of partitioned FSI simulations, separate flow and structure solvers are used, which requires some kind of coupling between both. The time step in both solvers is typically taken the same, but this unnecessarily leads to long calculation times when the time step is small due to stability reasons in one of the two solvers. Subcycling, the procedure where the time step of one solver is chosen smaller than the time step used in the other solver, may reduce the computational cost of the FSI simulation. The subcycling procedure can be either explicit or implicit, the latter implying the use of coupling iterations in each time step. Contrary to explicit subcycling, no stability analyses of implicit subcycling schemes are found in the literature. In this paper, the temporal stability of the implicit subcycling procedure is investigated. The one‐dimensional flow in an elastic cylindrical tube is studied analytically. The results of this analysis are subsequently compared to a partitioned two‐dimensional axisymmetric FSI calculation with implicit coupling between the flow and structure solvers. Abstract : In order to reduce the computational time required for strongly coupled fluid‐structure interaction (FSI) problems, subcycling is a highly relevant area of research. In this paper, subcycling in a strongly coupled FSI is analyzed both analytically and numerically. The effect of the time step ratio, the discretization scheme in the structural solver, and the subcycling scheme is investigated.