Estimation of added effects and their frequency dependence in various fluid–structure interaction problems

Abstract This paper focuses on a fluid–structure interaction topic—the determination of added effects caused by fluid forces acting on a body, considering the standard linear equation of motion. We present various problems that assume small-displacement oscillations of single and multiple bodies in inviscid irrotational (potential) flow or viscous incompressible flow in both closed domain and external flow. For inviscid flow, effects of geometric parameters on the added effects were studied. The presented results extend results known from the literature. For viscous flow, frequency dependence of the added effects was studied for a wide range of frequency. The added effects were computed from data from numerical simulations of fluid flow, where the body oscillations were modeled using the dynamic mesh approach. Effects of the phase shift caused by the dynamic mesh were addressed. The added mass was compared with the corresponding value determined for inviscid flow where applicable. The results show strong dependence of the added effects on many parameters, making their proper computation challenging even for simplified cases.