利用表面脉动压力探测转捩的数据处理方法研究

利用表面脉动压力探测转捩是很有前景的转捩探测技术,一般以脉动压力均方根的变化情况和功率谱作为判断依据.本文针对目前的信号处理方法仅适用于单点判断及判断效果差的问题开展研究.通过理论分析,提出了如下方法:(1)使用当地动压和零状态时传感器输出信号均方根的组合作为参考值来无因次化均方根数据；(2)选择合适的频程并用频程内的平均值表现功率谱.通过处理翼型表面脉动压力的实测数据,与传统方法进行了对比.研究表明:新的处理方法所得结果规律性好,更直观,易于沿流向多点的转捩判断.本文的工作可供风洞实验技术人员参考.

An Investigation on Data Processing in Transition Detection Using Surface Pressure Fluctuation

Transition detection based on surface pressure fluctuation is a promising technique of transition detection. Generally, the R.M.S.(Root Mean Square) change of pressure fluctuation and power spectrum are taken as judgement evidence. Aiming at the problems of current signal processing method (only applicable to single point judgement and poor effect of judgement), authors conducted this study. Through theoretical analysis, new methods are put forward:(1) nondimensionalization of the R.M.S. of pressure fluctuations by using combination of local dynamic pressure and R.M.S. of transducer singal in zero state; (2) to select suitable frequency range and express power spectral. The measured data of surface pressure fluctuation on an airfoil was compared with the results obtained by traditional method. Conclusions show that new data processing method has good regularity, is more visual and more suitable for multi-point mesurement in transition detection along flow direction. Above results may be helpful for engineers of wind tunnel.