Estudo numérico tridimensional da vibração induzida por vórtices sobre um cilindro rígido elasticamente apoiado com um e dois graus de liberdade

Abstract

This work addresses the response of a cylindrical structure to three-dimensional incident flow. Initially, the numerical code is validated using the fixed cylinder. Then, an investigation of the vortex-induced vibration response (VIV) is performed, in one and two degrees of freedom. In order, the cylinder will be supported by a spring and a damper and will be free to vibrate in the transverse direction and then also in the longitudinal direction to the flow. To solve the slightly compressible Navier-Stokes equations together with the dimensionless equation of cylinder motion, the Finite Differences Method and the third-order Runge-Kutta method are used for integration in time. The boundary conditions on the body are imposed using the Immersed Boundaries Method. The turbulent flows are solved using the Large Eddy Simulation (LES). The Smagorinsky model is used to simulate the dissipative effects of small scales. Results for temporal series of the drag coefficient, lift coefficients, vorticity contour, displacement amplitude, frequency and phase angle are analyzed. The present work is a pioneer in the three-dimensional numerical study of VIV in 2 degrees of freedom that analyzes in detail the wake and the vortex shedding modes.