ROLE OF THE FLUID RELAXATION-TIME IN LAMINAR ELASTICO-VISCOUS BOUNDARY-LAYERS

被引：5

作者：

HARNOY, A

机构：

[1] Department of Mechanical Engineering, University of Rhodesia, Salisbury, Mount Pleasant

来源：

RHEOLOGICA ACTA | 1979年 / 18卷 / 02期

关键词：

D O I：

10.1007/BF01542768

中图分类号：

O3 [力学];

学科分类号：

08 ; 0801 ;

摘要：

The stress relaxation effect is investigated in the flow of elastico-viscous fluids in laminar boundary layers. Examples of the exact 'similar' solutions of Falkner and Skan class have been extended to include the relaxation effect. In order to separate the effects of the relaxation and the first normal-stress difference, a rheological equation with a new material time derivative is used. This derivative is referred to a co-ordinate system attached to the principal directions of the strain rate tensor. The results show a reduction in the skin friction owing to the elasticity of the fluid in boundary layers having increasing shear rate downstream. Conversely skin friction increases in flows with decreasing shear rates downstream. Comparison with a former work yields the role of the first normal-stress difference. The results can explain the observed downstream shift of the separation point in elastico-viscous flow past a submerged cylinder. © 1979 Dr. Dietrich Steinkopff Verlag.

引用

页码：210 / 216

页数：7

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