时变平均风提取方法研究

非平稳风速模型将实测风速记录分解为时变平均风与平稳脉动风的叠加。研究提出利用脉动风平稳度指标确定时变平均风的方法,定义不同时距摩阻速度的比值为脉动风平稳度指标,在所有可能的选择中,最优时变平均风应使脉动风在满足平稳性要求的同时平稳度指标最大。应用于实测10分钟550组台风及3300组季风数据表明该提取方法合理有效。

On extraction approach for time-varying mean wind speed

The authors have suggested a non-stationary wind model to represent the strong typhoon or monsoon as summation of a time-varying mean wind speed(TVM) and a stationary fluctuating wind speed component.This paper presents an iterative approach to quantitatively extract the TVM from wind record.The main idea is to determine a proper TVM by checking the variation of degree of stationarity of the fluctuating wind speed component.For each wind record,TVM candidates are first obtained by empirical mode decomposition.The degree of stationarity of the fluctuating component is then quantified by ratio of friction velocity at different Reynolds averaging periods.The final TVM is determined when the degree of stationarity becomes larger than a threshold value and is the maximum.The applicability of the suggested approach is validated by 550 typhoon records of 10-min duration and 3300 monsoon records as well.