摘要
通过分析壁面切应力,比较了不同高宽比矩形通道宽边和窄边壁面摩擦阻力特性.结果表明宽边摩擦阻力随高宽比的减小而急剧增加;窄边摩擦阻力变化趋势与宽边相反,但变化幅度比宽边小;总摩擦阻力随高宽比的减小而增大.宽边摩擦阻力占总摩擦阻力的份额随高宽比的增加而减小,且高宽比越大,变化速率越慢.高宽比对窄边局部切应力的影响很小,对宽边局部切应力的大小和分布形状均有明显影响.采用能量梯度法,对不同高宽比矩形通道内单相层流--湍流转捩雷诺数进行求解,并将理论计算结果整理成多项式,其预测值和实验值有很好的一致性.
The frictional resistances for wide side and narrow side of rectangular channels with different aspect ratios are compared, by analyzing the wall shear stress. The results show that the frictional resistance of the wide side increases sharply as the aspect ratio decrease, of which shows the reversed trend in a smaller range for the narrow side. Therefore the total frictional resistance increases with the decreasing of the aspect ratio. The frictional resistance proportion for wide side out of the total decreases as the aspect ratio increases, more slowly for the larger aspect ratio. The aspect ratio has remarkable influence on both the magnitude and the distribution type of shear stress for wide side, whereas, it has limited influence on shear stress for narrow side. Additionally, the transition Reynolds number of laminar to turbulent flow is calculated by energy gradient method and a polynomial correlation is achieved. The predicted results show good agreement with the experimental data.
出处
《力学学报》
EI
CSCD
北大核心
2013年第3期331-336,共6页
Chinese Journal of Theoretical and Applied Mechanics
基金
国家自然科学基金资助项目(11175050
51076034)~~
关键词
高宽比
摩擦阻力
层流
能量梯度法
转捩雷诺数
aspect ratio, frictional resistance, laminar flow, energy gradient method, transition Reynolds number
