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Old   August 4, 2007, 11:30
Default Air cushion patterns
  #1
john anderson
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Looking for an online digram that shows the wake/wash pattern of a air-cushion vessel and or a hovercraft. Looking to compare and contrast such footprints with that of conventional, displaced vessels for a research project on riverbank erosion.
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Old   August 5, 2007, 21:01
Default Re: Air cushion patterns
  #2
Leo Lazauskas
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For a variety of wake images see: http://www.cyberiad.net/wakeimages.htm

Also see (for a variety of air cushion pressure distributions): "Wave Patterns and Minimum Wave Resistance for High-Speed Vessels", E.O. Tuck, D.C. Scullen and L. Lazauskas, 24th Symposium on Naval Hydrodynamics, Fukuoka, 2004. http://www.cyberiad.net/library/pdf/tsl02b.pdf

All the best, Leo.

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Old   August 6, 2007, 00:27
Default Re: Air cushion patterns
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john anderson
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got it. seems to be a lack of published material on transport carrying hovercraft.

jia
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Old   August 6, 2007, 04:08
Default Re: Air cushion patterns
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Leo Lazauskas
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The "FAST" series of conference proceedings has a few references, but there isn't much, around as you said. Also look at CCdoT which assessed many different types of sea-lift vessels including hovercraft, SES and some other hybrids.

I've done some calculations for large (>10000t) hovercraft travelling at 100+ knots, but I doubt that anyone would want to build such frightening things.

All the best, Leo.

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Old   August 6, 2007, 08:42
Default Re: Air cushion patterns
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john anderson
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is CCDOT California DOT ?

If you have stats on a larger hovercraft sure I'd be interested in taking a look at these.

b/r,

jia
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Old   August 6, 2007, 19:33
Default Re: Air cushion patterns
  #6
Leo Lazauskas
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Sorry, CCDoTT is: "Center For The Commercial Deployment Of Transportation Technologies"

The conference I was referring to was: "High-Speed Sealift Technology".

The most important conference documents to get are at: www.ccdott.org/Deliverables/1997/task2.0.1/task2.0.1_m.htm

There are many references you can glean from:

Lazauskas, L.,"Hydrodynamics of advanced high-speed sealift vessels", www.cyberiad.net/library/pdf/llmsc.pdf

For an examination of (unachievable?) optimal pressure distributions see:

Tuck, E.O. and Lazauskas, L., "Free-surface pressure distributions with minimum wave resistance", www.cyberiad.net/library/pdf/tl01.pdf

Cheers, Leo.
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Old   August 8, 2007, 01:06
Default Re: Air cushion patterns
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Leo Lazauskas
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It was a bit egotistical citing only my own papers. Anyone doing serious research on air-cushion vessels must look at the work of Lawrence J. Doctors who is probably the world's leading authority. In particular see: "On the use of pressure distributions to model the hydrodynamics of air-cushion vehicles and surface effect ships", Naval Engineers Journal, March 1993.

Now back to me again.

If you are interested in evaluating damage to the littoral zone by large fast ships, you might also consider the pressures induced on the sea-bottom. I've included some bottom pressure signatures for a large displacement vessel in: "The hydrodynamic resistance, wave wakes and bottom pressure signatures of a 5900t displacement air warfare destroyer", Dept. Applied Mathematics Report, The University of Adelaide. www.cyberiad.net/library/pdf/nibberluna0.pdf

Unfortunately I don't know enough to assess whether those pressures are significant in terms of disruption to sea-grass beds and the fauna that rely on them.

Regards, Leo.

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Old   August 8, 2007, 20:27
Default Re: Air cushion patterns
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john anderson
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thanks and obliged. after reading over your beta i read up on pressures and was wondering are studies available that shows the pressure bubble: depth and width of a hovercraft at different lift pressures ?

b/r,

jia
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Old   August 9, 2007, 22:29
Default Re: Air cushion patterns
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Leo Lazauskas
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I'm not sure what you mean by the "pressure bubble". Do you mean contour plots of the over-pressure, or do you mean the elevations of the free-surface under the pressure patch? Or something else?

Leo.

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Old   August 9, 2007, 23:42
Default Re: Air cushion patterns
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john anderson
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leo,

Can't rightly say but contour plots of the over-pressure and the elevations of the free-surface under the pressure patch seems to meet the issue.

that is what can be shown of underwater pressure depth under a hovercraft.

b/r

jia
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Old   May 8, 2010, 21:23
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  #11
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George
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I know that this is a three year old thread, but figured it was a good place to post this hovercraft paper I found recently.

Link:
Forty-Plus Years of Hovercraft Development, by David R. Lavis
http://personal.stevens.edu/~apiccol...TS%20Paper.pdf

Cheers, George/kach22i
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