A simplified model for fluid–structure interaction : a cylinder tethered by springs in a lid-driven cavity flow

Abstract

A simplified fluid–structure interaction model is presented, consisting of a cylinder tethered by a spring system interacting dynamically with the two-dimensional and incompressible lid-driven cavity flow. The fluid–structure interaction was solved in a partitioned way, having separate solvers for the fluid flow equations and the structural equations. The influence of the Reynolds number and spring constants on the cylinder motion and fluid flow was analyzed. Results show that as the Reynolds number increases, the secondary eddies grow in size and the primary eddy adapts to this change, shifting toward the center of the cavity. When the values of the spring constants are small (k=0.01N/m), such that the spring forces are weaker than the fluid drag force, the springs stretch freely and the cylinder motion is the direct result of the fluid dynamics action. For higher values of spring constants (k>0.01N/m), the cylinder motion reaches a maximum displacement, and the spring forces induce the cylinder to an oscillatory movement damped by the viscous fluid force; subsequently, the amplitude of the displacements decreases. As the Reynolds number increases, the cylinder motion is restricted within the mainstream fluid flow (considered the more energized region), having smaller displacements.