Nonlinear motion-induced aerodynamic forces on large hyperbolic paraboloid roofs using LES

Abstract

In this paper, the nonlinear characteristics of motion-induced aerodynamic forces on large-scale hyperbolic paraboloid roofs are numerically investigated using LES (large-eddy simulation). The mean and standard deviation (STD) of wind pressure coefficients on the rigid hyperbolic paraboloid roofs in the turbulent boundary layer are first simulated to validate the numerical models. Then the hyperbolic paraboloid roofs under forced excitation with different oscillation amplitudes are simulated to study the wind pressures on and the flow structures above the roofs. Moreover, the motion-induced aerodynamic forces, which are represented by the aerodynamic stiffness and damping forces, are also investigated with the harmonic balance method (HBM). It is found that the aerodynamic stiffness force is linearly proportional to the oscillation amplitude, but the aerodynamic damping force is nonlinearly dependent on the oscillation amplitude. The wind-induced responses of the large-scaled roof considering nonlinear motion-induced aerodynamic forces exhibit typically hardening non-Gaussian characteristics at the low reduced frequency, which are consistent with the probabilistic features of vortex-induced vibration (VIV) of slender structures.