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ridehpd
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Posted: May 04, 2010 - 07:42 AM
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Newbie

Joined: May 04, 2010 - 07:26 AM
Posts: 2
Location: San Diego, California
Status: Offline
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| I'm a high school student currently working on a calc/physics project for which I would like to use Euler's equations for fluid dynamics (http://en.wikipedia.org/wiki/Euler_equations_%28fluid_dynamics%29) to create a pressure gradient (the second equation) that I can use a surface integral with a variable planform area vector formula to create a very rough approximation of various planforms as velocity changes. I know that that is a practically useless formula since it does not incorporate viscosity or temperature changes, but a fun concept to work with. I have everything squared away, but I need to find a way to get the partial derivative for air density and the planform equations (but that's for another post). I'm thinking that they would come from Bernoulli's equation but I'm not sure. Anyone have any advice? |
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Sponsor
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Posted: Jun 18, 2013 - 7:14 AM
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F-16.net Sponsor
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cchief16
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Posted: May 04, 2010 - 05:43 PM
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Active Member

Joined: Oct 16, 2005 - 10:26 PM
Posts: 204
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| i have no clue what you just said |
_________________ F-16 crewchief
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Roscoe
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Posted: May 09, 2010 - 07:11 AM
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Elite 1K

Joined: Jun 29, 2004 - 09:14 PM
Posts: 1283
Location: Las Vegas
Status: Offline
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| Wow...I have a masters degree in this stuff (over 22 years ago however) and you lost me. Either I'm rusty or you're barking up the wrong tree. |
_________________ Roscoe
<b>"It's time to get medieval, I'm goin' in for guns"</b> - <i>Dos Gringos</i>
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motorman
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Posted: May 15, 2010 - 07:15 PM
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Enthusiast

Joined: Jul 02, 2005 - 02:12 AM
Posts: 24
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| I recall Bernoulli’s equation is valid for incompressible flow only, so I’d be surprised that would be what you were looking for given you are interested in a partial derivative for air density. In turbomachinery aerodynamics (and I suspect for air vehicles) we generally use (Reynolds-Average) Navier-Stokes which includes both viscous effects and compressible flows, the latter to capture shock behavior. Perhaps that is what you’re looking for. |
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That_Engine_Guy
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Posted: May 16, 2010 - 12:20 AM
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Elite 2K

Joined: Dec 14, 2005 - 05:03 AM
Posts: 2208
Location: Under the engine somewhere.
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Don't forget Newton, lots and lots of Newtonian stuff....
My favorite is the second law; "The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object."
Which all boils down to THRUST!
TEG |
_________________ [Airplanes are] near perfect, all they lack is the ability to forgive.
— Richard Collins
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r2d2
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Posted: May 24, 2010 - 06:36 AM
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Active Member

Joined: Nov 18, 2008 - 04:52 AM
Posts: 193
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Bernoulli's equations can be solved by Newton's equations of motion. Basically the same thing. I recall doing this in the faculty (OK, not in high school).
But as motorman said go for Navier-Stokes equations where you can calculate the pressure and the velocity of a point if you know the pressure and velocity of neighbour points. |
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