Dynamic Modelling and Analysis of Submerged Floating Tunnels

Abstract

Investigations are performed on the capabilities of Computational Fluid Dynamics (CFD) to model a transient transcritical flow around a Submerged Floating Tunnel (SFT). The aim of this inquiry is to examine the possibility of modeling the effect of Vortex Induced Vibrations (VIV) on a circular cylinder, through a coupling between a 2D CFD simulation, and a 3D FEM analysis of the structure trough strip theory. To validate such an approach, it is essential to verify that the CFD analysis yields accurate results. A simulation has been performed on the flow around a circular cylinder with Re=3.6⋅〖10〗^6, based on the solution of the 2D Unsteady Reynolds Averaged Navier-Stokes (URANS) equations with the Realizable k-ϵ turbulence model using enhanced wall treatment. The hydrodynamic values obtained is the time averaged drag coefficient (CD,avrg), the root-mean-square lift coefficient (CL,rms), and the non-dimensional shedding frequency (St). The analysis yields a St=0.26, which is within published experimental values, in contrast to published numerically obtained results.