关键词: ADV, 峰值降噪, 功率谱, 数据处理

Abstract:

ADV was usually used to measure three-dimensional momentary velocities of turbulent flow. However, this method is sensitive to external environment and instrument itself, which can lead to spike noise in collecting velocity time series. In order to obtain the true and high-frequency velocity signals of instantaneous turbulent flow, a new velocity signal pretreatment method should be put forward to filtrate the noise signal. Firstly the velocity data that is 3.5 times greater than sample standard deviation was revised; then the data signal variation of local area in sample is analyzed and furthermore the velocity data that is 2 times greater than sample standard deviation was reversed by interpolation method. So the power spectrum filtering method for filtrating instrument noise was put forward based on Fourier linear transformation. The analysis results of experimental data shows that the number of mended data is less than 12% of the total; the velocity power spectrum of processed data is more aligned with Kolmogorov power spectrum. The proposed method has an obvious effect in despiking of high frequency noise, which provides more accurate analysis basis for turbulence characteristics analysis.

Key words: ADV, despiking, power spectrum, data processing