# P2D: A Simple 2D Planing Program

Discussion in 'Software' started by Leo Lazauskas, Feb 20, 2012.

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### Leo LazauskasSenior Member

P2D: A Simple 2D-Planing Program

The attached (Windows) program produces some accurate solutions
of the 2D planing equation based on the work of E.O. Tuck.

The attached pdf manual has instructions for installing and running
the program.

After a bit more work, and when time permits, I will upload a version
for cambered plates, and some "splashless" geometries.

IMPORTANT!
P2D will not be of any use whatsoever to those wanting a method for
predicting the performance of real planing vessels. Other methods,
such as those of Savitsky, will be more useful.

The 3D problem is much more difficult than our simple case!
Those interested in the fully 3D planing problem should refer to
recent papers and those cited in their bibliographies.
A good start is:
Taravella, Brandon M. and Vorus, William S.,
"A general solution to low-aspect-ratio flat-ship theory"
Journal of Engineering Mathematics,
No. 71, pp. 171-184, 2011.

Finally, many thanks to boatdesign.net for providing a forum where
such esoteric hydrodynamic oddities can be shared and discussed.

Leo.

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### daiquiriEngineering and Design

I think it is a very good educational tool, for those who want to understand qualitatively, on a simplest example of a flat plate, what happens under and behind a planing vessel's hull, why it happens and a variation of pressures, wave elevations, trim and squat over a range of speeds.
Thanks for this one, Leo.

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### Leo LazauskasSenior Member

Thanks, Slavi.
One area of recent application is the drag of the bow seal of Surface Effect
Ships (SES). Some researchers (e.g. L.J. Doctors) are using 2D planing
theory in an attempt to explain some components of the drag.

It is a very tough problem and there is a lot more to do in both theory and
experiments. The US Navy is conducting some intensive experiments at a
very large facility. There is an interesting article describing the tests in the
Jan. 2012 edition of "Marine Technology".

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### CWTeebsAnomalyGenerator

What page? I'm searching the digital edition of MT but can't find it Leo.

- CWTeebs

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### Leo LazauskasSenior Member

The article is called:
"Testing on a Large Scale",
Pages 46-48.

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### CWTeebsAnomalyGenerator

Part of the analyses I did for validating POWERSEA involved looking at pressure distributions from various NACA airfoil experiments.

There's a paper by Royce, including full scale planing hull experimental pressure distributions (e.g. to identify chine wet/chine dry transition), that describes the 2d impact theory under the guise of zarnick.

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### CWTeebsAnomalyGenerator

Hi Mr. Lazauskas,

You are probably already aware of this, but for others who aren't I found a program called JavaFOIL on CAELinux (Ubuntu 10.04 core) that might be useful with P2D.

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### CWTeebsAnomalyGenerator

Another screenie with the flowfield done in JavaFOIL. Another program that does airfoil techniques is XFOIL which I believe came out of MIT.

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### DCockeySenior Member

Could someone explain the relevance of the analysis of airfoils immersed in an "infinite" fluid to a body planing on a free surface?

10. ### CatBuilderPrevious Member

Would this not be accurate for submerged foils such as rudders and dagger boards on a displacement craft?

Is planing a requirement for the discussion?

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### DCockeySenior Member

JavaFoil would be suitable for the limited cases where a 2-dimensional analysis is valid.

The title of this thread is P2D: A Simple 2D Planing Program.

My question, "Could someone explain the relevance of the analysis of airfoils immersed in an "infinite" fluid to a body planing on a free surface?" was not rhetorical. CWTeeb has brought up the flow and pressure distribution around airfoils as relevent to planing analyisis. POWERSEA which he mentions is a planing analysis code. I'm interested in understanding the relevance.

A discussion on the relevance of 2-D airfoil analysis software to rudders and centerboards would be better in it's own thread, not one on planing models.

12. ### CatBuilderPrevious Member

Of course, you are correct. How I managed to lose track of the title of the thread is a window into in a lazy Sunday mind.

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### CWTeebsAnomalyGenerator

One of the force components POWERSEA resolves is circulation lift calculated using a heavily customized panel method. JavaFOIL is a simple panel method that could be used to integrate the concepts of longitudinal pressure distributions, and, when compared to P2D the idea of the free surface condition can be fully understood for the 2D case. I didn't think it was off topic at all, quite the contrary, I found the connections somewhat obvious. That said, I won't be offended if the links to JavaFOIL are removed from the thread, in which case I would apologize for having erroneously posted them in the first place.

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