Measuremens of Wall Shear-Stress in Skewed Turbulent Boundary Layer on a Ratating Cylinder

额定圆柱体倾斜湍流边界层壁面剪应力的测量

基本信息

批准号：
11650168
负责人：
YAMASHITA Shintaro
金额：
$ 2.3万
依托单位：
Gifu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650168/
关键词：
Wall Shear Stress Turbulence Rotating Body Boundary Layer Skewed Velocity Momentum Integral Equation Hot-Wire Anemometer Buffer Fitting

项目摘要

This research aims to measure the wall shear stress in the turbulent boundary layer with skewed velocity profile on a thin cylinder rotating at high speed in an axial stream. The methods to measure the wall shear stress are those to utilize Laser Doppler Velocimetry, miniature hot-wire probe, wall flow tracer, heat tracer, momentum integral equation, and so forth.In the measurement using the miniature hot-wire probe, I- and V-type probes with tungsten wire of 3 μm in diameter were used, and the rotated hot-wire method was employed for I-type probe. Experiments were made nearly in the whole range of the turbulent boundary layer on the cylinder of 1200 mm in length with no rotation and with rotation at the speed ratio, the ratio of the peripheral velocity of the cylinder to the main flow velocity, equal to one. The wall shear stresses were estimated from applying the buffer-fitting method to the data of the near-wall velocity obtained from these miniature probes. Substituting the wall sh … More ear stresses obtained into the momentum integral equation in the form integrated with respect to the x-direction, the balance of this equation was examined, and it was found that its balance was moderately kept ; the estimated wall shear stresses were fairly reliable. The method to obtain the wall shear stress directly from the momentum integral equation was investigated, and, on the basis of an uncertainty analysis, we had a prospect that if the measurement at one section were repeated more than about ten times an accurate value of the wall shear stress would be estimated.The methods using Laser Doppler Velocimetry are to measure the velocity profile in the vicinity of the wall, and there are roughly two methods. One method is to measure in the rotating system, and to do so it is necessary to incorporate the optical system into the rotating body. We are now ready to make experiment for an ad hoc model of a rotating body. The other is to measure in the stationary frame, and the measuring optical system is manufactured by trial. In a word, the study of the methods using LDV are continued.It is our judgment in this research that there is no advantage in the methods using wall flow or heat tracers unless the accuracy of the wall shear-stress value obtained by these methods is far superior to the one obtained by the other methods, partly because of the difficulty of setting the devices or sensors for these methods on the rotating wall at high speed. Less

这项研究旨在测量湍流边界层中的壁剪应力，并在轴向流中高速旋转的薄缸上偏斜的速度曲线。 The methods to measure the wall shear stress are those to utilize Laser Doppler Velocimetry, miniature hot-wire probe, wall flow tracer, heat tracer, momentum integral equivalency, and so forth.In the measurement using the miniature hot-wire probe, I- and V-type probes with tungsten wire of 3 μm in diameter They were used, and the rotated hot-wire method was carried出于I型探针。在1200毫米的圆柱上的整个湍流边界层的整个范围内进行了实验，没有旋转，并且以速度比以旋转为单位，速度比，圆柱体的外围速度与主流速相同，等于一个。通过将缓冲型拟合方法应用于从这些微型问题获得的近壁速度数据中估计壁剪应力。代替壁sh…在相对于x方向集成的形式中获得的更多早期应力，检查了该方程的平衡，发现其平衡是适度保持的；估计的壁剪应力相当可靠。研究了直接从动量积分等效性中直接获得壁剪应力的方法，并且，根据不确定性分析，我们有一个前景，如果将它们重复的测量值重复大约十倍以上，则可以估计壁剪应力的准确值。使用Laser Doppler Velocimetry的方法，可以估算VIC的范围。一种方法是在旋转系统中测量，这样做有必要将光学系统纳入旋转体。现在，我们准备进行旋转体临时模型的实验。另一个是在固定框架中测量，并且测量光系统是通过试验制造的。在一句话中，继续对使用LDV的方法进行研究。这是我们在这项研究中的法官，除非这些方法获得的壁剪切压力值的准确性远远优于其他方法获得的方法，否则使用壁流或热示踪剂的方法没有优势，部分原因是很难将这些方法设置为这些方法或传感器上的速度迅速旋转壁上的速度较高。较少的