VIV modelled using simplified cable dynamics coupled to sub-critical cylinder flow simulations in a moving reference frame

Abstract

This work focuses on the study of the phenomenon of vortex-induced vibrations in overhead lines under the effect of weak winds. Full three-dimensional simulation is not feasible because of the high length to width aspect ratios of the overhead lines. Thus a quasi-3D method based on strip theory is adopted in this work. This method decouples the system of interactions between the overhead line and the wind into a series of sub-systems. The fluid flow in each sub-system is represented as a series of independent rigid oscillating cylinder flows that are only coupled through the transmission line model. To avoid the use of a moving mesh for the fluid domain, a moving reference frame approach is employed. In this approach, the coordinate axes of the flow simulation are attached to the oscillating cylinder and an acceleration term in the flow equations accounts for the cable motion. Moreover, in order to take into account the turbulent effect in the flow, turbulence models, including RANS, LES and DES, are evaluated for the present application involving flows in the sub-critical regime. Finally, numerical test cases are performed in order to validate the turbulence models and the moving reference frame approach, then cable dynamics test cases are conducted to validate the quasi-3D method.