Buaria Dhawal, Sreenivasan Katepalli R
Tandon School of Engineering, New York University, New York, New York 11201, USA.
Max Planck Institute for Dynamics and Self-Organization, 37077 Göttingen, Germany.
Phys Rev Lett. 2022 Jun 10;128(23):234502. doi: 10.1103/PhysRevLett.128.234502.
The scaling of acceleration statistics in turbulence is examined by combining data from the literature with new data from well-resolved direct numerical simulations of isotropic turbulence, significantly extending the Reynolds number range. The acceleration variance at higher Reynolds numbers departs from previous predictions based on multifractal models, which characterize Lagrangian intermittency as an extension of Eulerian intermittency. The disagreement is even more prominent for higher-order moments of the acceleration. Instead, starting from a known exact relation, we relate the scaling of acceleration variance to that of Eulerian fourth-order velocity gradient and velocity increment statistics. This prediction is in excellent agreement with the variance data. Our Letter highlights the need for models that consider Lagrangian intermittency independent of the Eulerian counterpart.
通过将文献数据与各向同性湍流精细直接数值模拟的新数据相结合，显著扩展雷诺数范围，研究了湍流中加速度统计量的标度律。较高雷诺数下的加速度方差偏离了基于多重分形模型的先前预测，该模型将拉格朗日间歇性表征为欧拉间歇性的扩展。对于加速度的高阶矩，这种差异更为显著。相反，从一个已知的精确关系出发，我们将加速度方差的标度律与欧拉四阶速度梯度和速度增量统计量的标度律联系起来。这一预测与方差数据高度吻合。我们的快报强调了需要考虑独立于欧拉对应物的拉格朗日间歇性的模型。
