Why airplanes fly aerodynamics
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Transcript of Why airplanes fly aerodynamics
Presentation on
Aerodynamics of Plane
Presented by:Arindam Sarkar
5th semester. Roll no. 106Mechanical Engineering
PRIYADARSHINI COLLEGE OF ENGINEERING
Why Airplanes Fly
Aerodynamics
Institute of Computational Fluid Dynamics
Aerodynamics?
• Aero – means Air• Dynamics – means Motion• Aerodynamics – the study of air in motion
• Important Point: Air is “Viscous”
Uh, that means it’s Sticky
Airplane Parts
Fuselage (Body)
Wing
Horizontal Stabilizer
Vertical Stabilizer Empennage(Tail)
Engine
4 Forces of Flight
Weight
Center of Gravity (CG)
Drag
Newton’s 1st Law Applies
Thrust
Newton’s 3rd Law Applies
Lift
Newton’s 3rd Law Applies
Weight
Lift
Thrust Drag
Think About ItIt’s “Tug-a-War”
The motion of the airplane through the air depends on the relative strength and direction of the forces we’ve discussed.
If the 4 forces are balanced, the aircraft cruises at constant velocity and altitude.
If the forces are unbalanced, the aircraft accelerates in the direction of the largest force.
More on Lift … Lift in Depth
What’s it take to create lift?
Air and motion.
How do we explain lift?Newton’s Laws of Motion and Bernoulli’s Principal are used to explain lift.
Newton’s Third Law states that for every action there is an equal and opposite reaction.
Stream Lines
Streak Lines 10° AOA
Newton’s 2nd and 3rd Laws Apply
Note: DownwashAir Accelerated Down
AOA: Angle Of Attack - the angle that the wing meets the oncoming air.
Streak Lines 0° AOA
Streak Lines -12° AOA
Streak Lines 10° AOA
Newton’s 2nd and 3rd Laws Apply
Note: DownwashAir Accelerated Down
AOA: Angle Of Attack - the angle that the wing meets the oncoming air.
Airfoil
Total Aerodynamic Force(Sum of Pressure and Shear)
Lift
Drag
V
Venturi Tube
• Bernouli’s first practical use of his theorem
• Where are venturi tubes used today?
What is a wing?
• A wing is really just half a venturi tube.
A fluid (and air acts like a fluid) speeds up as it moves through a constricted space
Bernoulli’s Principle states that, as air speeds up, its pressure goes down.
Bernoulli's Principle: slower moving air below the wing creates greater pressure and pushes up.
Bernoulli’s Principle: Air moving over the wing moves faster than the air below. Faster-moving air above exerts less pressure on the wing than the slower-moving
air below. The result is an upward push on the wing--lift!
Pressure Field
Result of the accelerated flow on top and decelerated flow on bottom.
Bernoulli’s Principal: pressure variation around the wing results in a net aerodynamic pushing up.
http://www.grc/nasa.gov/WWW/Wright/airplane/shape.html
Velocity Vectors
Forces on the Airfoil
Forces act along the entire surface.
Which way does the liftingforce actually work?
Net Force
Combining all the forces.
Lift Relates to AOA
Zero Lift at Zero AOA
That’s Why Airplanes Fly.
References
• “The Beginner’s Guide to Aeronautics”, NASA http://www.grc.nasa.gov/WWW/K-12/airplane/
• “IRROTATIONAL PLANE FLOWS OF AN INVISCID FLUID”; Colombini, Marco; UNIVERSITY OF GENOA http://www.diam.unige.it/~irro/
• Institute of Computational Fluid Dynamicshttp://www.icfd.co.jp/index-e.htm
• See How It Flies; Denker, John S.http://www.av8n.com/how/#mytoc
• “Bumblebees finally cleared for takeoff”; Wang, Z. Jane; Cornellhttp://www.news.cornell.edu/releases/March00/APS_Wang.hrs.html
• DNS of Separated Flow around NACA0012 Airfoil; Shih, et al. (1992, 1995); University of Texas http://www.uta.edu/faculty/hshan/research/gallery.shtml
Thank you
Lift Relates to AOA
Zero Lift at Zero AOA