NUMERICAL SIMULATIONS OF SINUSOIDALLY OSCILLATING CROSS-FLOW AROUND A CIRCULAR CYLINDER

A numerical study is conducted to investigate a sinusoidal oscillatory cross flow around a smooth circular cylinder. A numerical model based on the Reynolds-averaged Navier-Stokes (RANS) equations with the k - omega Shear Stress Transport (SST) turbulence model is implemented, using the open source C++ package OpenFOAM (R). The study focuses on the level of confidence in using two-dimensional numerical simulations for the predictions of the inherent transient behaviour of the highly nonlinear hydrodynamic induced loads. Simulations are conducted for two values of Keulegan-Carpenter (KC) number corresponding to inertia-dominated and drag-inertia regimes, for a fixed value of the frequency parameter beta. Boundary layer separation structures and their temporal evolution are investigated and visualized by means of turbulence kinetic energy contours. Moreover, inline forces inertia and drag coefficients of Morison loads decomposition are found and validated against previous experimental results in literature. Finally, transverse forces and their spectral content is investigated and validated. The study shows that the magnitude and frequency of the unsteady hydrodynamic induced forces coefficients are well reproduced and are in a very good agreement with the experimental observations.