Tip-splitting instabilities in the channel Saffman-Taylor flow of constant viscosity elastic fluids
Tip-splitting instabilities in the channel Saffman-Taylor flow of constant viscosity elastic fluids
复制标题
恒定粘度弹性流体萨夫曼泰勒流通道中的尖端分裂不稳定性
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
Maher
中科院分区：
文献类型：
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作者：
Vlad;Maher
用Boger流体研究了通道Hele-Shaw流动中粘弹性流体的粘性指进增长。我们已经发现，在Boger流体中生长的粘性指在高速下对尖端分裂是不稳定的，在牛顿粘性指稳定的区域中。没有观察到类似于不稳定性的现象。我们表明，在剪切和拉伸流中产生的粘弹性正应力差达到非常高的值，在剪切和拉伸速率可比的尖端分裂的发病时，在手指的尖端，和流体变得高度各向异性。粘弹性应力会影响手指的动力学特性，导致手指尖端分裂失稳。
Boger fluids are used to study viscous fingering growth in viscoelastic fluids in channel Hele-Shaw flow. We have found that the viscous finger growing in the Boger fluid is unstable to tip splitting at high velocities, in a regime where a Newtonian viscous finger is stable. No fracturelike instabilities were observed. We show that the viscoelastic normal stress differences arising in shear and extensional flow reach very high values at shear and extensional rates comparable to those achieved at the tip of the finger at the onset of tip splitting, and the fluid becomes highly anisotropic. The viscoelastic stress could affect the dynamics of the finger and induce the tip-splitting instability.