Vortex induced loads on marine risers

The Vortex-Induced Vibration on a circular cylinder is investigated as basis for applications on dynamics of risers used in offshore oil and gas industry. The numerical solution of the two-dimensional Reynolds Averaged Navier-Stokes equations is obtained for a circular cylinder laterally supported by a spring and a damper and free to oscillate in the transversal direction. The Beam and Warming implicit factorization scheme is used to solve the governing equations and the Baldwin-Lomax model is used to simulate the turbulent flow in the wake of the cylinder. The proposed numerical solution was able to provide a good picture of the real physics of the phenomenon including the Kármán vortex street effects on the lift and drag coefficients. The numerical results for the transversal oscillation amplitude are compared to experimental data showing a fairly precise agreement even at the difficult to simulate regime of the lock-in phenomenon.