阵风及其谱模拟

作用于海洋工程结构物的风力一般可分为恒定分量和变动分量两部分，认为前者是由于稳定风速所致，后者是由于风速脉动引起的。在实验室中为了恰当地模拟海上环境，不但要实现稳定风速的模拟，而且变动风速也要满足一定要求，这即是阵风谱的模拟。本文在风速的脉动是随机的，并服从高斯分布，且是由无限多正弦风叠加而成的基础上，叙述了海洋工程模型试验中如何实现阵风谱的模拟，并给出了模拟实例。

GUST SIMULATION

The wind force on the offshore structures is roughly ten percent in global loads and can, in general, be divided into a steady component and a dynamic component. The former is assumed to be due to steady wind velocity, the later, due to fluctuations of the wind velocity. When most of wind energy contained in wind field is close to the natural periods of the moored floating structures, the fluctuations in the wind velocities may introduce low frequency motion of the moored structures. The procedure of the wind spectrum simulation is described in this paper based on the assumption that the fluctuation of wind velocity is Gaussian and the gusts are composed of infinite sinusoidal winds. Given wind velocity and center height of wind pressure over sea level the simulation is performed with API spectrum in the ocean engineering basin of JTU State Key Laboratory. The measured wind velocity records were analyzed by FFT method to get the wind spectrum. Some results of the spectra are given in the paper.