风琴管射流自激频率的确定对于调制射流达到强烈的振荡冲蚀效果具有重要作用，而目前难以准确获得，主要原因在于斯特劳哈尔数Sd大小与射流参数、空化数及喷嘴结构参数等诸多因素有关。通过分析风琴管射流自激振荡机理，探讨了自激频率与空化数的关系；基于流体压力脉动信号检测法获取风琴管射流的时域信号及其频谱，并运用“三波共振”理论确定射流的自激频率，依据涡街理论推导出斯特劳哈尔数；通过试验分析环境围压、射流工作压力及射流空化数对自激频率的影响，获得斯特劳哈尔数与射流空化数的关系曲线；基于最小二乘法得到斯特劳哈尔数的拟合公式，建立不同工作压力及围压条件下射流自激频率的估算模型。试验结果表明，给定喷嘴结构条件下，斯特劳哈尔数受环境围压、射流工作压力影响，其取值主要由空化数确定。斯特劳哈尔数的取值范围以估算模型来代替，减少了选取斯特劳哈尔数的盲目性，提高了自激频率的理论计算精度。揭示了斯特劳哈尔数的影响因素及其变化规律，能为自振射流技术在深海领域的应用研究提供理论依据。
The self-excited frequency of the organ-pipe waterjet plays a key role in the modulation of the jet to achieve strong oscillation and erosion, while it is difficult to be obtained accurately. The main reason is that the value of the Strouhal number is associated with the jet parameters, the cavitation number and the nozzle structure parameters. The self-resonating oscillation mechanismof organ-pipe waterjet is discussed, and the relationship between the self-excited frequency and the cavitation number is analyzed. The pressure signal within pipeline is detected to obtain the jet spectrum, and according to the "triad resonance" theory, the self-excited frequency is distinguished. Furthermore, the influence of the confining pressure, the jet working pressure and the cavitation number on the frequency property are analyzed, and then the relation curve between the Strouhal number and the cavitation number is acquired. The approximate fitting formula of the Strouhal number is obtained based on the least square method, then the estimation model of jet self-excited frequency is established. The test results show that, with a given nozzle structure, the value of the Strouhal number is only related to the cavitation number. The value range of the Strouhal number is replaced by the estimation model, so that the theoretical calculation accuracy of self-excited frequency is improved. The results provide a theoretical basis for the application and study of self-resonatingwaterjet technology in deep-sea area.
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