SIMULTANEOUS MEASUREMENTS OF VELOCITY AND PRESURE FLUCTUATIONS IN TURBULENTFLOWS

(1)研制了一种由压力传感器和X型热线传感器组成的组合探头，用于同时测量湍流中的速度和脉动静压。研制了自动测量系统和高速数据处理系统。(2)为了调节射流中的旋涡运动，将该探针应用于在Strouhal数St = 0.82下激励的圆形射流的测量。利用所获得的数据，对湍流能量输运方程中的对流项、湍流扩散项、压力输运项和产生项进行了估算，并讨论了湍流能量收支与湍流结构的关系。结果表明，所研制的探头是可靠的。特别是它是一个显着的结果，本研究的长期的压力传输的实验估计。(3)在轴对称混合层中，压力传输（速度-压力相关）进行了估计和讨论与涡运动。根据实验数据对湍流能量输运方程和湍流街道输运方程所采用的湍流模型进行了讨论。结果表明，在大尺度涡旋运动占主导地位的区域，两种模式都不满足要求。研究结果对改进湍流模型有一定的参考价值。(4)讨论了圆形和矩形射流的声源，重点讨论了压力测量所检测到的旋涡运动。利用脉动声压的二阶时间导数估计声源。结果表明，涡源与涡的配对和切割连接有关。

(1) The combined probe consisting of pressure and X-type hot-wire sensor was developed to measure velocity and fluctuating static-pressure simultaneously in turbulent flows. The systems for the automatic measurement and the high-speed date-processing were developed.(2) The probe was applied to the measurement of the circular jet excited at Strouhal number St = 0.82 in order to regulate the vortex motion in the jet. Using the acquired date, the terms of convection, turbulence diffusion, pressure transport and production of the turbulence energy transport equation were estimated, and turbulence energy budget were discussed in relation to the turbulence structure. The result shows the reliability of the developed probe. In particular it is a significant result of the present study that the term of pressure transport was estimated experimentally.(3) In the axisymmetric mixing layer, the pressure transport (velocity-pressure correlation) was estimated and discussed in relation to the vortex motion. The turbulence models used in the turbulence-energy transport equation and the Reynolds-street transport equation were discussed by the experimental data. The result reveals that the models are not satisfied in the region where the large-scale vortex motion dominates. The result is useful to improve the turbulence models.(4) The sound sources of circular and rectangular jets were discussed focusing on the vortex motions detected by the pressure measurements. The sound sources were estimated by the second time-derivatives of fluctuating static-pressure. The result indicates that the sources are related to pairing and cut-and-connection of vortices.