A double diffusive lock-exchange flow with small density difference
Yoshida, J; Nagashima, H; Ma, Wen-Ju; Yoshida, J; Institute of Physical and Chemical Research, 2-1 Hirosawa, Wakoshi, Saitama 351-01, Japan; Present address: Tokyo University of Fisheries, Tokyo, Japan; Nagashima, H; Institute of Physical and Chemical Research, 2-1 Hirosawa, Wakoshi, Saitama 351-01, Japan; Ma, Wen-Ju; Institute of Physical and Chemical Research, 2-1 Hirosawa, Wakoshi, Saitama 351-01, Japan; Present address: Institute of Mechanics, Chinese Academy of Science, Beijing, China
Журнал:
Fluid Dynamics Research
Дата:
1987-12-01
Аннотация:
An experiment on center lock-exchange flow is carried out when the density difference is very small. Two cases (one-component fluid and two-component fluid) are investigated for comparison. The experimental results indicate that there is a substantial difference in appearance between one-component gravity currents and two-component currents when the density difference is extremely small. For a large initial density difference Δϱ<sub>0</sub>, either current spreads with constant velocity proportional to √Δϱ<sub>0</sub>. When Δϱ<sub>0</sub> becomes small, different tendencies are noticeable in the current velocity in these two cases. For the one-component case, U decreases to zero as Δϱ<sub>0</sub> approaches zero. For the two-component case, U also becomes small, but does not tend to zero, as Δϱ<sub>0</sub> approaches zero. This suggests that even if the initial water densities are exactly the same, double diffusive effects can produce inhomogeneity of density and induce the current.
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