This work deals with the experimental study of transient flow regimes occurring in the laboratory model of a hydraulic turbine draft tube at a change in the control parameters of setup. The transition from the partial load regime, when a precessing vortex core is formed, to the best efficiency point without a core is considered. To set accurately the speed of runner rotation and the flow rate of the working medium, the setup was controlled by special software. To ensure accurate multiple reproduction of a given transition cycle between two regimes, the control program has been upgraded. Using a specially developed procedure of phase averaging of a laser Doppler anemometer (LDA) signal recorded during multiple repetitions of transient regimes, the velocity profiles were obtained for different phases of changing the setup operating conditions.

中文翻译：

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瞬态运行状态下引流管模型中旋流的演变

这项工作涉及在水轮机尾水管的实验室模型中，在设置的控制参数发生变化时发生的瞬态流动状态的实验研究。考虑了在形成进动涡流芯时从部分负载状态到没有芯的最佳效率点的过渡。为了准确设置流道旋转速度和工作介质的流量，该设置由专用软件控制。为了确保两个状态之间给定过渡周期的准确多次复制，控制程序已升级。使用专门开发的多次平均瞬态记录过程中记录的激光多普勒风速计（LDA）信号的相位平均程序，可以获取改变设置操作条件的不同相位的速度曲线。