Probability Distribution Function of Near-Wall Turbulent Velocity Fluctuations
-
摘要: 采用大涡模拟方法，模拟槽道湍流，获得了不同雷诺数情形下的槽道流大涡模拟数据库．在此基础上，获得了流向和垂向脉动速度的概率分布函数，并运用假设检验，分析了其与正态分布的定量差别．进一步计算了流向和垂向脉动速度的偏斜度、平坦度，讨论了二者在粘性子层、过渡区和对数律区的变化．同时，讨论了粘性子层、过渡区和对数律区流向和垂向脉动速度概率分布函数的特点及其与湍流猝发的高速流下扫和低速流喷发事件的关系．最后，分析了雷诺数对流向、垂向脉动速度分布的影响．Abstract: By large eddy simulation (LES), turbulent databases of channel flows at different Reynolds numbers were established. Then, the probability distribution functions of the streamwise and wall-normal velocity fluctuations were obtained and compared with the corresponding normal distributions. By hypothesis test, the deviation from the normal distribution was analyzed quantitatively. The skewness and flatness factors were also calculated. And the variations of these two factors in the viscous sub-layer, buffer layer and log-law layer were discussed. Still illustrated were the relations between the probability distribution functions and the burst events) sweep of high-speed fluids and ejection of low-speed fluids) in the viscous sub-layer, buffer layer and log-law layer. Finally the variations of the probability distribution functions with Reynolds number were examined.
-
[1] Sechet P.Guennec B Le.The role of near wall turbulent structures on sediment transport[J].Wat Res,1999,33(17):3646—3656. doi: 10.1016/S0043-1354(99)00072-X [2] Nino Y,Garcia M H.Experiments on particle-turbulence interactions in the near-wall region of an open channel flow: implications for sediment transport [J].J Fluid Mech,1996,326:285—319. doi: 10.1017/S0022112096008324 [3] Brodkey R S,Wallace J M,Eckelmann H.Some properties of truncated turbulence signals in bounded shear flows[J].J Fluid Mech,1974,63:209—224. doi: 10.1017/S0022112074001108 [4] Kim J,Moin P,Moser R D.Turbulence statistics in fully developed channel flow at low Reynolds number[J].J Fluid Mech,1987,177:133—166. doi: 10.1017/S0022112087000892 [5] Moin P,Kim J.Numerical investigation of turbulent channel flow[J].J Fluid Mech,1982,118:341—377. doi: 10.1017/S0022112082001116 [6] 钱宁，万兆惠.泥沙运动力学[M].北京：科学出版社，1986. [7] LI Jia-chun. Large eddy simulation of complex turbulent flows: physical aspects and research trends[J].Acta Mechanica Sinica,2001,17(4):289—301. doi: 10.1007/BF02487457 [8] Smagorinsky J.General circulation experiments with the primitive equations—Ⅰ the basic experiment[J].Mon Weather Rev,1963,91:99—164. doi: 10.1175/1520-0493(1963)091<0099:GCEWTP>2.3.CO;2 [9] Pope S B.Turbulent Flows[M].Cambridge, UK: Cambridge University Press, 2000. [10] 张强，周济福，李家春.基于槽道流LES数据库的湍流猝发检测研究[J].中国科学，G辑，2005,35(3):292—307. -
点击查看大图
计量
- 文章访问数: 2356
- HTML全文浏览量: 57
- PDF下载量: 1209
- 被引次数: 0
下载:
