Numerical study on self-excited forces and flow fields for a thin plate under a sinusoidal non-stationary wind condition

Abstract

The self-excited forces and flow fields around a thin plate under stationary and sinusoidal non-stationary wind conditions were simulated using the computational fluid dynamics method. The differences between the simulated self-excited force results and calculated results based on Scanlan's linear flutter theory under the non-stationary wind condition were analyzed from the perspective of flow field characteristics. Furthermore, the effects of different torsional amplitudes on the thin plate's self-excited forces under the non-stationary wind condition were investigated. The results showed that there are significant nonlinear effects of self-excited forces on the thin plate for the non-stationary wind, with large differences between the simulated and calculated amplitudes for each harmonic component. An obvious flow pressure gradient distribution is observed along the thin plate for the non-stationary wind, and the flow pressure around the thin plate is closely related to the slope of the wind speed. The non-stationary incoming wind aggravates the disturbances in the shear layer at the leading edge of the thin plate, leading to deviations between the simulated and calculated self-excited forces. As the torsional amplitude increases, there is no longer a linearly proportional relationship between the self-excited forces and torsional amplitude under the non-stationary wind condition, and more severe flow separations and influence ranges of shedding vortex occur around the thin plate.