Eighteenth Symposium on Naval Hydrodynamics (1991) / Chapter Skim
Currently Skimming:
Ship Internal Waves in a Shallow Thermocline: The Supersonic Case
Ship Internal Waves in a Shallow Thermocline: The Supersonic Case
Pages 567-582
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 567... ...
ABSTRACT We develop a general theory of ship internal waves in a thermocline of moderate thickness below a well mixed upper layer, when the ship is traveling faster than the fastest internal waves. This theory provides both the kinematical pattern earlier discussed by Keller and Munk, and also the amplitude of the internal waves (the deflection of the top of the thermocline)
|
From page 568... ...
recently reported at a Workshop held at Farnborough under the aegis of the British Remote Sensing Society (Workshop Proceedings, 1990~. The RAE team has systematically measured in the water, internal wave wakes produced by a number of ships traveling over shallow thermoclines with a depth of the order of the ship draft as well as above water, visual, and radar signatures due to the internal waves.
|
From page 569... ...
= 0, since no internal waves are generated ahead of the ship in the supersonic case. In addition we expect the first wave at the ship to be given a net initial downward impetus due to the early action of the bow of the ship.
|
From page 570... ...
Therefore, in cases where ship internal wave patterns are visible from above, oceanographic surveys of shallow thermocline characteristics may be made by remote observation. We have calculated numerically the crest lines for a range of F and Ah, using the eqns.
|
From page 571... ...
(kh:F) The shipform amplitude factor will determine the order of magnitude of the interracial wave in a large part of the wake.
|
From page 572... ...
It is this particular "coincidence" which result in measurable internal wave patterns for large distances downstream under circumstances which prevail at Loch Linnie, for example. We do not believe that this "coincidence" depends critically on the shape of the ship, or the shape of the thermocline, or the hypersonic Froude number, although the nondimensional magnitude of the wave elevation will clearly decay as the thermocline depth, h, increases beyond the draft of the ship.
|
From page 573... ...
229. Hughes, B.A., "Surface Wave Wakes and Internal Wave Wakes Produced by Surface Ships," Proceedings of the 15th Symposium on Naval Hydrodynamics, National Academy Press, 1986.
|
From page 575... ...
too -~ ~F ' 5 . ~ / h 0~ 0 1 Go 200 300 ITS f00~ ~ 5 ~ ~ ~ h ~ ~ 0~ X / h ~0 7 6~00 10C ~ 501 10, (/ ~ ~ o" ~ DO 200 o 300 X / 40O 500 600 ~,~ 10, t/6 ~ 1 0 100 20n 300 IT 0~76~00 0~ X / h ~500 [~ internal Wave Crest ' I 6_ _and Mach Line ~ddO)
|
From page 576... ...
Wave Numbers Along Crest Lines ( solid ) & Trough Lines ( dashed )
|
From page 577... ...
Waveform Amplitude Factor 577 i l .
|
From page 578... ...
. Thermocline Displacement Patterns ( Near Field )
|
From page 579... ...
. Thermocline Displacement Patterns ( Near Field 579
|
From page 580... ...
Near Field Wake Patterns 1.
|
From page 581... ...
Crestline Wave Amplitudes 581
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.