DRAG REDUCTION BY POLYMERS

被引:179
作者
BERMAN, NS
机构
关键词
D O I
10.1146/annurev.fl.10.010178.000403
中图分类号
O3 [力学];
学科分类号
08 ; 0801 ;
摘要
The main object of this review is to examine the behavior of individual molecules or groups of molecules in turbulent pipe flow and boundary-layer flow and to relate this behavior to observed gross flow and experiments on turbulent structure. Only recent results are discussed, and the reader should consult the above references for earlier studies. Molecules that are effective in drag reduction have molecular weights above 10**5. In solution they are usually randomly coiled so that they form tangled balls filled with solvent. Good solvents interact with the macromolecules, causing expansion of the ball but preventing flow within the ball (when the external flow is laminar). Interactions between the external flow and the inner parts of the ball must be present in turbulent flow and perhaps in concentrated solutions. Drag reduction is best described by observations of gross-flow rate and pressure drop in turbulent pipe flow.
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页码:47 / 64
页数:18
相关论文
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