Max-Planck Institute for Dynamics and Self-Organization, 37077 Göttingen, Germany.
Phys Rev Lett. 2013 Jul 12;111(2):024501. doi: 10.1103/PhysRevLett.111.024501. Epub 2013 Jul 9.
We present a study of the energy transfer in the bulk of a turbulent flow with dilute long-chain polymer additives. Based on prior work by Tabor and de Gennes [Europhys. Lett. 2, 519 (1986); Physica (Amsterdam) 140A, 9 (1986)], we propose a theory on the energy flux into the elastic degrees of freedom of the polymer chains. This elastic energy flux, which increases as the length scale decreases, gradually reduces the energy transferred to smaller scales through turbulence cascade and hence suppresses small scale fluctuations. The balance of the elastic energy flux and the turbulence energy cascade gives an elastic length scale, which describes the effect of polymer elasticity on turbulence in the inertial range. Predictions of this new "energy flux balance theory" agree excellently with our experimental results.
我们研究了含有长链聚合物添加剂的湍流本体中的能量传递。基于 Tabor 和 de Gennes 的先前工作[Europhys. Lett. 2, 519 (1986); Physica (Amsterdam) 140A, 9 (1986)]，我们提出了一个关于聚合物链弹性自由度能量通量的理论。随着尺度的减小，这种弹性能量通量增加，逐渐减少通过湍流级联传递到较小尺度的能量，从而抑制小尺度波动。弹性能量通量和湍流能量级联的平衡给出了一个弹性长度尺度，它描述了聚合物弹性对惯性范围内湍流的影响。这种新的“能量通量平衡理论”的预测与我们的实验结果非常吻合。
