Abstract
The early free-surface flow due to an impulsively started point sink in a semi-infinite fluid is analytically studied by employing a power series expansion in time. The full surface elevation to second order is calculated, as well as the third-order elevation at the surface center just above the sink. Gravity enters into the problem only in the third-order surface elevation. A Froude number is defined here with respect to the sink strength and the initial submergence depth. A critical value for the Froude number is analytically determined which is related to dip formation at the free surface. Its value is 15-1/2=0.2582. This critical value is shown to be in good agreement with experimental data and earlier works on dip formation in a container that is drained by a hole in the bottom.
Original language | English |
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Pages (from-to) | 1368-1375 |
Number of pages | 8 |
Journal | Physics of fluids. A, Fluid dynamics |
Volume | 5 |
Issue number | 6 |
DOIs | |
State | Published - 1992 |