INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING Int. J. Numer. Meth. Engng 2009; 78:757–778 Published online 2 December 2008 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/nme.2503 Analysis of the block Gauss–Seidel solution procedure for a strongly coupled model problem with reference to fluid–structure interaction M. M. Joosten, W. G. Dettmer and D. Peri´ c ∗, † Civil and Computational Engineering Research Centre, School of Engineering, Swansea University, Swansea SA2 8PP, Wales, U.K. SUMMARY The block Gauss–Seidel procedure is widely used for the resolution of the strong coupling in the computer simulation of fluid–structure interaction. Based on a simple model problem, this work presents a detailed analysis of the convergence behaviour of the method. In particular, the model problem is used to highlight some aspects that arise in the context of the application of the block Gauss–Seidel method to FSI problems. Thus, the effects of the time integration schemes chosen, of relaxation techniques, of physical constraints and non-linearities on the convergence of the iterations are investigated. Copyright 2008 John Wiley & Sons, Ltd. Received 16 July 2008; Revised 10 September 2008; Accepted 6 October 2008 KEY WORDS: partitioned solution methods; block Gauss–Seidel procedure; fluid–structure interaction 1. INTRODUCTION A fluid–structure interaction (FSI) problem features a fluid domain and a structural domain, which are separated by an interface. An efficient strategy for the computer simulation of FSI should allow for the employment of different numerical discretization techniques with non-matching grids or meshes for the fluid and solid domains. The fluid could, for example, be discretized with a ∗ Correspondence to: D. Peri´ c, Civil and Computational Engineering Research Centre, School of Engineering, Swansea University, Swansea SA2 8PP, Wales, U.K. † E-mail: d.peric@swansea.ac.uk Copyright 2008 John Wiley & Sons, Ltd.