LES analysis on aeroelastic instability of prisms in turbulent flow

Abstract

This paper discusses the aeroelastic instability of prismatic structures on the basis of the numerical results by large eddy simulation for turbulent flows around a square and a rectangular cylinders. This type of aeroelastic instability is a classical problem continuing for over 30 years , so there have been a number of studies to understand the physical meanings by theoretical or experimental approach. From the wind engineering point of view, the turbulence effect on unstable oscillations should be clarified. Turbulence of the oncoming flows changes sensitively the behavior of separated shear layers and the vortex formation around a prism, so we need to investigate details of the flow structures under unstable oscillations, as well as the aeroelastic characteristics of a prism. Over 30 years have passed since the start, current Computational Fluid Dynamics technique makes it possible to analyze the above matters and give a solution. First, we examine the inflow homogeneous turbulence generated by the statistical method, which is utilized for study of aerodynamics of prisms in turbulent flows. Second, we investigate the turbulence effects on aerodynamic characteristics of stationary prisms to validate the numerical model. Finally, we clarify the aeroelastic instability of prisms in smooth and turbulent flows and its physical mechanism is discussed by the visualized flow structure around an oscillating prism.