Experiment on turbulent flow in rotating smooth channel with 1D hot wire
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摘要: 采用一维热线详细测量了不同雷诺数下及较高旋转数条件下旋转光滑直通道内湍流边界层及主流的速度型,在此基础上构建适用旋转数范围更广的旋转通道对数律的修正公式,分析了旋转效应对壁面摩擦速度的影响。实验过程中雷诺数范围是15000~25000,旋转数范围是0~0.444。通道壁面为室温,流体与壁面之间无热交换。结果表明:旋转对于通道截面速度型影响很大;旋转导致速度型整体向后缘面偏转,但最高速度出现在靠近前缘面的区域;后缘面无量纲平均速度型分布顺序与旋转数排列次序相一致,在对数律区符合对数律规律。壁面剪切应力在前缘面随着旋转数的增大而先单调递减,而在后缘面的变化趋势与此相反。旋转状态下修正的对数律公式斜率随着旋转数的增加而单调递减且在后缘面递减的趋势逐步有所减缓,并提出了对数律区的旋转修正公式,公式的误差范围控制在15%以内。Abstract: In order to obtain the velocity models of turbulent boundary layer and mainstream in rotating smooth straight channels at different Reynolds numbers and higher rotation numbers,a correction formula for the logarithmic law of rotation channels with a wider range of rotation numbers was constructed,the hot wire was used to measures the average velocity and wall friction velocity at four different flow locations in a rotating smooth straight channel. The Reynolds number and rotation number respectively ranged from 15000-25000 and 0-0.444,the wall of the channel was at room temperature and there was no heat exchange between the fluid and the wall. Results showed that rotation had a great influence on the velocity of channel section. The rotation led to the overall deflection of the velocity model to trailing side,but the highest speed occurred in the area near the leading side;the dimensionless averaged velocity model near the trailing side was strictly arranged in the order of rotation number,and logarithmic law was distributed in the logarithmic law area. At the same time,wall shear stress monotonously decreased with the increase of the number of rotations at the leading side,and the trend of the change at the trailing side was contrary to this. The slope of the logarithmic law formula modified by rotation decreased monotonously with the increase of rotation number and decreased gradually at the trailing side. The rotation correction formula of the logarithmic law area was put forward,and the error of the formula was controlled within 15%.
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