Numerical calculation of decaying isotropic turbulence using the LET theory
Numerical calculation of decaying isotropic turbulence using the LET theory
复制标题
利用 LET 理论对衰减各向同性湍流进行数值计算
DOI：
10.1017/s0022112084001270
复制
发表时间：
1984
影响因子：
3.7
通讯作者：
V. Shanmugasundaram
中科院分区：
文献类型：
--
作者：
W. McComb;V. Shanmugasundaram
采用局部能量转移理论（LET） （McComb 1978）计算了四种不同初始谱在中低微尺度雷诺数（Rλ高达约40）下的自由衰减湍流。能量谱、耗散谱和能量转移谱以及偏度因子的计算结果都与著名的直接相互作用近似（DIA: Kraichnan 1964）的预测非常吻合。然而，LET的能量传递和进化偏度因子值高于DIA。这可能与LET产生无限雷诺数下能谱的k−5/3定律有关。然后对LET方程进行数值积分，计算高雷诺数下各向同性湍流的衰减。在演化的微尺度雷诺数Rλ为533时，得到了能量、耗散率和惯性传递率的波数谱，以及相关的积分参数。LET的预测与实验结果和拉格朗日历史理论（Herring & Kraichnan 1979）非常吻合。特别是，发现纯欧拉LET理论与基于应变的拉格朗日历史近似相当接近；进一步的比较表明，这种一致性也适用于低雷诺数。
The local-energy-transfer (LET) theory (McComb 1978) was used to calculate freely decaying turbulence for four different initial spectra at low-to-moderate values of microscale Reynolds numbers (Rλ up to about 40). The results for energy, dissipation and energy-transfer spectra and for skewness factor all agreed quite closely with the predictions of the well-known direct-interaction approximation (DIA: Kraichnan 1964). However, LET gave higher values of energy transfer and of evolved skewness factor than DIA. This may be related to the fact that LET yields the k−5/3 law for the energy spectrum at infinite Reynolds number. The LET equations were then integrated numerically for decaying isotropic turbulence at high Reynolds number. Values were obtained for the wavenumber spectra of energy, dissipation rate and inertial-transfer rate, along with the associated integral parameters, at an evolved microscale Reynolds number Rλ of 533. The predictions of LET agreed well with experimental results and with the Lagrangian-history theories (Herring & Kraichnan 1979). In particular, the purely Eulerian LET theory was found to agree rather closely with the strain-based Lagrangian-history approximation; and further comparisons suggested that this agreement extended to low Reynolds numbers as well.