Center of pressure
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The center of pressure is the point on a body where the sum total of pressure acts, causing a force, but no moments. The point at which the sum of these forces, from the various surfaces of the body, passes through the body is the center of pressure. Mathematically it can be said that the net pressure force on the body acts through this point. However, this concept is not realized in practice, as moment couples cannot be nulled out.
[edit] Aircraft
The center of pressure on an airfoil is different from an aircraft's center of lift, which is effectively located at the wing's aerodynamic center.[1]
The upper and lower surfaces of a wing have varying centers of pressure at a given angle of attack. At a low angle of attack, the upper and lower surfaces will typically experience low pressures. The upper surface's center of pressure develops an upward force, while the lower surface's center of pressure develops a downward force. Generally the upward force is located further aft of the downward force and creates a forward aerodynamic pitching moment.
At a high angle of attack, the upper surface has extremely low pressure relative to the surrounding air, while the lower surface experiences a higher pressure. The net upward force generated by an airfoil at any angle of attack is lift, which acts from constant point regardless of the angle of attack.
[edit] See also
[edit] References
- ^ Preston, Ray (2006). Aerodynamic Center. Aerodynamics Text. Selkirk College. Retrieved on 2006-04-01.
- Hurt, Hugh H., Jr. (January 1965). Aerodynamics for Naval Aviators. Washington, D.C.: Naval Air Systems Command, United States Navy, 16-21. NAVWEPS 00-80T-80.
- Smith, Hubert (1992). The Illustrated Guide to Aerodynamics, 2nd ed., New York: TAB Books, 24-27. ISBN 0-8306-3901-2.
