Pal Nairita, Perlekar Prasad, Gupta Anupam, Pandit Rahul
Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India.
TIFR Centre for Interdisciplinary Sciences, 21 Brundavan Colony, Narsingi, Hyderabad 500075, India.
Phys Rev E. 2016 Jun;93(6):063115. doi: 10.1103/PhysRevE.93.063115. Epub 2016 Jun 24.
We study the challenging problem of the advection of an active, deformable, finite-size droplet by a turbulent flow via a simulation of the coupled Cahn-Hilliard-Navier-Stokes (CHNS) equations. In these equations, the droplet has a natural two-way coupling to the background fluid. We show that the probability distribution function of the droplet center of mass acceleration components exhibit wide, non-Gaussian tails, which are consistent with the predictions based on pressure spectra. We also show that the droplet deformation displays multifractal dynamics. Our study reveals that the presence of the droplet enhances the energy spectrum E(k), when the wave number k is large; this enhancement leads to dissipation reduction.
我们通过对耦合的相场Cahn-Hilliard-纳维-斯托克斯(CHNS)方程进行模拟,研究了由湍流驱动的活性、可变形、有限尺寸液滴的平流这一具有挑战性的问题。在这些方程中,液滴与背景流体存在自然的双向耦合。我们表明,液滴质心加速度分量的概率分布函数呈现出宽的、非高斯尾部,这与基于压力谱的预测一致。我们还表明,液滴变形表现出多重分形动力学。我们的研究表明,当波数k较大时,液滴的存在增强了能谱E(k);这种增强导致耗散减少。