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

本研究旨在测量轴向流高速旋转的薄圆柱体上具有倾斜速度剖面的湍流边界层中的壁面剪应力。测量壁面剪应力的方法是利用激光多普勒测速仪、微型热测速仪。线探头、壁流示踪器、热示踪器、动量积分方程等。在使用微型热线探头进行测量时，使用直径为 3 μm 的钨丝的 I 型和 V 型探头I型探头采用旋转热丝法，在1200 mm长度的圆柱体上几乎全范围进行了湍流边界层不旋转和速比旋转的实验。圆柱体的圆周速度与主流速度之比等于 1，通过将缓冲拟合方法应用于从这些微型探头获得的近壁速度数据来估计壁剪切应力。 …更多耳朵将获得的应力以相对于 x 方向积分的形式代入动量积分方程，检验该方程的平衡性，发现其平衡性保持适度；该方法是相当可靠的。研究了直接从动量积分方程获得壁面剪应力，并且在不确定性分析的基础上，我们预计，如果在一个截面上重复测量十次以上，就可以得到壁面剪应力的准确值将被估计。使用激光多普勒的方法测速是测量壁面附近的速度分布，大致有两种方法：一种是在旋转系统中进行测量，为此需要将光学系统合并到旋转体中。现在准备对旋转体的特设模型进行实验，另一种是在固定框架中进行测量，并试制了测量光学系统。总之，继续对使用LDV的方法进行研究。我们在这项研究中的判断是没有优势使用壁流或伴热器的方法，除非通过这些方法获得的壁面剪应力值的精度远远优于其他方法获得的值，部分原因是这些方法在旋转上设置设备或传感器的困难高速时墙少。