用人工产生的拟湍流信号检验相干结构的检测方法

An Evaluation of Effectiveness of the Detection Algoritnms with Artificial Turbulence Signal

本文利用计算机产生拟湍流脉动信号，将数据进行频谱分析和能谱分析，发现湍流中相干结构不仅包合低频成分还包含一定数量高频成分，因而简单地认为湍流中低频部分是相干结构而高频部分是小尺度脉动，来确定相干结构能量在湍流中所占成分是不科学的；本文还将得到的数据用几种条件采样方法检测相干结构数量和位置，以此判断检测方法的优劣，发现就这类信号而言ＭＵ—ＬＥＶＥＬ法要比ＶＩＴＡ法准确性要高一些。

In this paper,a kind of artificial turbulence signal is produced by computer to simulate turbulence With embedded coherent structures.Analysing the frequency and energy of this signal,it is found that coherent structures contain not only low frequency but also high frequency.That means to assume low frequency band is contributed by coherent structures while high frequency band is totally contributed by small scale disturbance is in general incorrect. This signal is also used to test the effectiveness of various conditional methods in detecting coherent structures.It is found that the MULevel method is better than the VITA method.