Effects of the Reynolds number on a scale-similarity model of Lagrangian velocity correlations in isotropic turbulent flows
Effects of the Reynolds number on a scale-similarity model of Lagrangian velocity correlations in isotropic turbulent flows
复制标题
雷诺数对各向同性湍流中拉格朗日速度相关性尺度相似模型的影响
DOI：
10.1007/s10483-018-2387-6
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发表时间：
2018-10
期刊：
影响因子：
--
通讯作者：
Jin Guodong
中科院分区：
文献类型：
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作者：
Shi Zhaoyu;Chen jincai;Jin Guodong
HE， G. W.， JIN， G. D., and ZHAO， X.，最初建立了一个用于各向同性湍流中示踪粒子相对色散的两点两时间拉格朗日速度相关（LVC）的尺度相似模型。物理学报，2009,33(2):481 - 481。该模型可表示为两点欧拉空间相关和色散速度v。色散速度是指一个运动粒子离开另一个固定粒子的速率。数值验证了尺度相似模型在远高于原始值（Rλ= 66,102）的高Taylor微尺度雷诺数（373）下的鲁棒性。研究了尺度相似模型中雷诺数对色散速度的影响。结果表明，尺度相似模型在较高雷诺数下更为精确，因为不同初始空间分离下的两点拉格朗日速度相关性通过色散速度坍缩为一种普遍形式。此外，由数值数据得到的色散速度V由Kolmogorov速度vη≡η/τη归一化，其中η和τη分别为Kolmogorov空间和时间尺度，雷诺数为r λ。
A scale-similarity model of a two-point two-time Lagrangian velocity correlation (LVC) was originally developed for the relative dispersion of tracer particles in isotropic turbulent flows (HE, G. W., JIN, G. D., and ZHAO, X. Scale-similarity model for Lagrangian velocity correlations in isotropic and stationary turbulence.Physical Review E,80, 066313 (2009)). The model can be expressed as a two-point Eulerian space correlation and the dispersion velocityV. The dispersion velocity denotes the rate at which one moving particle departs from another fixed particle. This paper numerically validates the robustness of the scale-similarity model at high Taylor micro-scale Reynolds numbers up to 373, which are much higher than the original values (Rλ= 66, 102). The effect of the Reynolds number on the dispersion velocity in the scale-similarity model is carefully investigated. The results show that the scale-similarity model is more accurate at higher Reynolds numbers because the two-point Lagrangian velocity correlations with different initial spatial separations collapse into a universal form compared with a combination of the initial separation and the temporal separation via the dispersion velocity. Moreover, the dispersion velocity V normalized by the Kolmogorov velocityVη≡η/τηin whichηand τηare the Kolmogorov space and time scales, respectively, scales with the Reynolds numberRλasobtained from the numerical data.