A semi-implicit coupling technique for fluid-structure interaction problems with strong added-mass effect

This paper is concerned with the numerical simulation of fluid-structure interaction problems involving an incompressible viscous flow and an elastic structure. A semi-implicit coupling technique is presented which strongly couples the added-mass term of the fluid (pressure stress) to the structure, while the remaining terms are only loosely coupled. A thorough numerical analysis is carried out to verify the accuracy of the proposed method by comparing its results to experimental data and other numerical results from the literature. The performance and accuracy of the proposed method are also compared against a fully implicit coupling technique. Numerical tests show that semi-implicit coupling significantly reduces the computational cost of the simulations without undermining either the stability or the accuracy of the results. The question of implicit or explicit coupling of the dynamic mesh step is addressed by evaluating its effect on the overall accuracy and performance of the semi-implicit method. The implicit coupling of the dynamic mesh step is found to slightly improve the accuracy, while significantly increasing the computational cost. Moreover a comparison is made on the performance of the semi-implicit method with different interface solvers.