Coupling between structural and fluid dynamic problems applied to vortex shedding in a 90m steel chimney

摘要

A simplified fluid-structure interaction approach is used to study the dynamic behaviour of a particular 90. m steel chimney under vortex-induced vibrations. Navier-Stokes equations for incompressible flow are solved in 2D in several transverse planes of the line-like structure. The resultant pressure field is introduced using standard FEM interpolation techniques, together with the dynamical behaviour of the structure and its boundary conditions. A fractional step scheme is used to solve the fluid field. In each fluid plane, the displacements are taken into account considering an Arbitrary Lagrangian Eulerian approach. The stabilisation of incompressibility and convection is achieved through orthogonal quasi-static subscales, an approach that is believed to provide a first step towards turbulence modelling. In order to solve the structural problem, a special one-dimensional element for thin walled cross-section beams is implemented. The standard second-order Bossak method is used for the time integration of the dynamic problem. The wind is modelled as an incompressible fluid acting on the structure in a series of planes, transverse to the structure that are supposed to be independent among them. For each period of time, the fluid problem is solved, the aeroelastic analysis is carried out and the geometry of the mesh of each fluid plane is updated according to the structure displacements.