An experimental investigation of the relative diffusion of particle pairs in three-dimensional turbulent flow

被引:244
作者
Ott, S [1 ]
Mann, J [1 ]
机构
[1] Riso Natl Lab, DK-4000 Roskilde, Denmark
关键词
D O I
10.1017/S0022112000001658
中图分类号
O3 [力学];
学科分类号
08 ; 0801 ;
摘要
The particle tracking (PT) technique is used to study turbulent diffusion of particle pairs in a three-dimensional turbulent flow generated by two oscillating grids. The experimental data show a range where the Richardson-Obukhov law [r(2)] = C epsilont(3) is satisfied, and the Richardson-Obukhov constant is found to be C = 0.5. A number of models predict much larger values. Furthermore, the distance-neighbour function is studied in detail in order to determine its general shape. The results are compared with the predictions of three models: Richardson (1926), Batchelor (1952) and Kraichnan (1966a). These three models predict different behaviours of the distance-neighbour function, and of the three, only Richardson's model is found to be consistent with the measurements. We have corrected a minor error in Kraichnan's (1996a) Lagrangian history direct interaction calculations with the result that we had to increase his theoretical value from C = 2.42 to C = 5.5.
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页码:207 / 223
页数:17
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