Hybrid simulations for the mechanical degradation of polymer solution by turbulence

在本研究中，我们通过进行数值模拟，包括长链聚合物的切断过程，研究了湍流对聚合物溶液的机械降解及其对湍流统计的影响。已知聚合物添加剂可以降低湍流的动能耗散。研究发现，长链聚合物对湍流统计数据（如动能耗散）的影响较大。当聚合物的弹性更强时，即使湍流已经充分衰减，也可以通过拉伸聚合物来维持湍流运动。在低于柯尔莫哥洛夫尺度的波数范围内，动能谱呈现幂律衰减特征。我们还发现，由于长链聚合物切割数量的减少，动能耗散的降低率随着时间的推移而逐渐降低。

In this study we examined the mechanical degradation of polymer solution by turbulence and its effects on turbulence statistics by performing the numerical simulations which include the cut-off process of long-chain polymers. It is known that the kinetic energy dissipation of turbulent flows is reduced by polymer additives. It was found that the longer chain polymers have larger influence on the turbulence statistics like the kinetic energy dissipation. When the elasticity of polymers was much stronger, turbulent motions were maintained by stretching polymers even when the turbulence sufficiently decayed. Then the kinetic energy spectrum showed the characteristic power-law decay in the wavenumber range below the Kolmogorov scale. We also found that the reduction rate of the kinetic energy dissipation was gradually decreased with time due to the decreasing of the number of longer chain polymers by cutting.