Fluid Dynamic Problems in Cold Regions

寒冷地区的流体动力学问题

基本信息

批准号：
63302027
负责人：
KIYA Masaru
金额：
$ 4.35万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Co-operative Research (A)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63302027/
关键词：
Fluid Mechanics Heat Transfer Cold Regions Snow Drifting Ice Formation Snow Fences Model Snow Model Experiment 北方圏熱工学

项目摘要

1. A turbulent separated-and-reattaching flow is one of the most fundamental flows which are associated with the effectiveness of snow fences and shelters, the obstruction of drivers' sight during snow drifting, etc. Two- and three-dimensional separated flows were experimentally studied to obtain the time-mean velocities, turbulence properties, flow unsteadiness due to the shedding of large-scale vortical structure, and means of their manipulation. These results are likely to be similar to those of a wide range of separated-and-reattaching flows.2. An experimental study was made to investigate characteristics of the freezing heat transfer of layered ice-water flow in a circular pipe, in which cooled air and water flow in the same direction. The experiment was performed under a variety of conditions of water discharge, water temperature, tube-wall temperature, air discharge, and water level. Particular attention was focused on photographic visual observation of the developing ice layer … More along the tube wall. It was observed that there were two different regions characterizing the ice formation, one of which was the freeze-off region, and the other was the steady-state region. Conditions for the freezeoff onset were obtained in terms of an empirical formula.3. The formation of ice growth occurring in branched pipes which contained water was made over a range of Reynolds number, and the cooling temperature ratios. From the flow visualization studies, the branched pipe flowing water was first blocked by ice formation ; subsequently the main pipe downstream of the branched portion was frozen off, and eventually the main pipe downstream of the branched portion was blocked by ice formation. This shows that freezing of the remaining water in the branched portion results in the pipe rupture at around the branched portion. The transient behavior of the ice formation was expressed in terms of the pressure loss and Reynolds number for various cooling temperature ratios.4. Flow around a snow shelter consisting of cascade of elliptic wings was numerically studied by solving the Navier-Stokes equations by the use of a body-fitted coordinate to obtain the aerodynamic forces acting on the wing, the velocity distribution, and the effectiveness of blowing off snow on the ground level. Velocity and turbulence measurements were also made in wake of a porous plate to evaluate the extent of detached low-velocity region downstream of the plate. These results gave excellent information on design of effective snow fences and shelters. Less

1。湍流分离和恢复的流动是与雪围栏和庇护所的有效性相关的最基本流量之一，是驾驶员在积雪中的视线的目标等。在实验上是在实验上研究的两维和三维分离的流量是获得时间均值的速度，湍流，湍流，构成不变的范围的均值。这些结果可能类似于广泛的分离及其连接流的结果。2。进行了一项实验研究，以研究圆形管中分层冰水流的冷冻热传递的特征，其中冷却的空气和水流沿相同方向流动。实验是在水流，水温，管壁温度，空气排放和水位的各种条件下进行的。特别关注的是对发育中的冰层的摄影视觉观察……更多的是沿着管墙。据观察，有两个不同的区域来表征冰的形成，其中一个是冷冻区域，另一个是稳态区域。根据经验公式获得了冻结发作的条件3。在包含水的分支管道中发生的冰生长的形成是在一系列雷诺数和冷却温度比的范围内形成的。从流动可视化研究中，首先通过冰形成阻塞了流动的管道。随后，将分支部分下游的主管道冻结了，有时将分支部分下游的主管子被冰形成阻塞。这表明，分支部分中剩余的水的冻结导致管道破裂在分支部分周围。冰形成的瞬态行为是根据压力损失和各种冷却温度比的雷诺数表示的。4。通过使用车身拟合的坐标来求解Navier-Stokes方程的围绕由椭圆机级联组成的积雪避难所的流动是数值研究的，从而获得了作用在机翼上的空气动力，速度分布的空气动力以及在地面上吹雪的有效性。在多孔板后，还进行了速度和湍流测量，以评估板下游的脱离低速区域的程度。这些结果提供了有关有效的雪栅栏和庇护所设计的出色信息。较少的