超声波多普勒流速测量方法的信息窗区域控制研究

通过对超声波多普勒信息窗区域的控制，实现了管流内部流速的分区测量，研制出的发射传感器和接收传感器，能够分别产生细小的发射声束和接收声束，使信息窗区域面积能够控制在很小的范围内，位置也被控制在设计值处，满足了分区测量的要求，设计的模拟管道流动装置，能够提供管道流动截面上某一小区域上的流速，为分区测量提供了信号源，成功地进行了信息窗区域面积的控制和位置的实验测量，测量值与设计值吻合得很好。     

基于PDA的微生物分类检测方法

以ＰＤＡ技术为基础，利用两组ＰＤＡ接收器及高速数字信号处理技术，进行也污水中微生物分类检测的初步研究，对ＰＤＡ技术在环境监测中的应用进行了探索。     

多勒普加宽斯塔克效应调制分析

用半经典理论分析了含多勒普加宽的斯塔克效应调制，使用密度矩阵近似，导出了吸收线附近ＮＨ３分子的吸收系数和调制度表达式，实验研究了１０．７８４μｍ波长的斯塔克效应调制特性，调制频率１ＭＨｚ时，调制度达到３３％。     

Proton induced thermal stress-wave measurements using a Laser Doppler Vibrometer

Thermal stress-waves are generated in the solid target material when the proton beam interacts. These stress waves excite natural oscillations of the target or cause plastic deformations. Hence, an experimental setup with a laser Doppler vibrometer [CITE] was developed to investigate free surface vibrations of cylindrical targets. The target configurations for RIB and conventional neutrino beams (CNGS project) were investigated to analyze proton induced thermal stress-wave generation and propagation.     

气－固流动系统无干扰测量设备的新进展

为了在气－固流动系统过程中确定运输特性，证实理论预报和仪设计程序公式化，必须对气－固两相流的各相质量流量、密度和局部地区的流速进行测量，对于某种相（诸如一群固体颗粒）的密度进行直接测量时需要有一种基本测量标准，激光多普勤相测定仪在一定条件下可以测定局部地区的瞬时密度，因而可用作基本测量标准，其它光学方法及中子束方法由于需要用质量流量进行标定，因而只能用作间接的测量标准，本文对无干扰测试设备的新进展进行了综述，对激光多普勒测速仪（ＬＤＶ）、相多普勤颗粒分析仪（ＰＤＰＡ）直至核磁共振测速仪的性能、限制因素及应用前景作了概述和讨论。     

涡流管流动结构及能量分离性能LDV实验研究

设计了直径为30 mm的可组装式透明涡流管以实现主流道可视化,并采用二维激光多普勒测速(LDV)技术得到子午面时均流场．研究了不同冷流比(0.1~0.9)、主流道长度(360、600、900和1 200 mm)、入口压力(0.01、0.02 MPa)下的轴向速度和径向速度分布,特别是折返流边界对能量分离性能的影响．LDV结果表明,时均轴向速度分布具有较好的轴对称性,不同压力下流动结构具有相似性,径向速度远小于轴向速度．增加冷流比会导致折返流边界径向膨胀,揭示了在过短管和过长管中两种能量分离恶化机制——过短管中折返流面过厚,过长管中轴向滞止点向冷端靠拢．该结果验证了以往所提出的优化准则,同时可以说明滞止点并不是涡流管中的一种基本流动结构．     

Velocity profile measurement by ultrasonic doppler method

The ultrasonic velocity profile measuring method has been developed at PSI for application in fluid mechanics and fluid flow measurement. It uses pulsed ultrasonic echography together with the detection of the instantaneous Doppler shift frequency. This method has the following advantages over the conventional techniques: (1) an efficient flow mapping process, (2) applicability to opaque liquids, and (3) a record of the spatiotemporal velocity field. After a brief introduction of its principle, the characteristics and specifications of the present system are given. Then examples in fluid engineering for oscillating pipe flow, T-branching flow of mercury, and recirculating flow in a square cavity are described that confirm the method's advantages. Several other works under way by other investigators are introduced. A potential for in-depth study of fluid dynamics is demonstrated by several examples from an investigation of modulated wavy flows in a rotating Couette system. The position-averaged power spectrum and the time-averaged energy spectral density were used to study the dynamic characteristics of the flow, and subsequently the velocity field was decomposed into its intrinsic wave structure based on two-dimensional Fourier analysis.     

The development of an axisymmetric curved turbulent wall jet

An experimental study has been carried out of the low speed Coanda wall jet with both streamwise and axisymmetric curvature. A single component laser Doppler technique was used, and by taking several orientations at a given point, values of the three mean velocities and five of the six Reynolds stresses were obtained. The lateral divergence and convex streamwise curvature both enhanced the turbulence in the outer part of the jet compared with a plane two-dimensional wall jet. The inner layer exhibited a large separation of the positions of maximum velocity and zero shear stress. It was found that the streamwise mean velocity profile became established very rapidly downstream of the slot exit. The profile appeared fairly similar at later downstream positions, but the mean radial velocity and turbulence parameters showed the expected nonself preservation of the flow. Removal of the streamwise curvature resulted in a general return of the jet conditions toward those expected of a plane wall jet. The range and accuracy of the data may be used for developing turbulence models and computational techniques for this type of flow.