How to Measure Pressure Distribution
- 1). Find the pressure distribution coefficient using the appropriate formula to understand the pressure distribution on a wing. For example, this would be important in determining the air pressure if you were designing a wing. The formula is:
Pressure Distribution = (Pressure 1 - Pressure (Free Stream))/(.5 * air density * free stream velocity^2) - 2). Solve for the numerator of the formula by searching for the observed pressure minus the expected pressure. The expected pressure is termed the Free Stream Pressure. For example, you find that the observed pressure is 500 atm (standard atmosphere) and the expected pressure is 450 atm.
- 3). Solve for the air density (symbolized by the Greek letter rho). Air density is equal to the absolute pressure of air divided by the gas constant times the temperature. For example, you find that air density is 300 kg/m^3 (kilograms per meter cubed).
- 4). Find the value of the free stream velocity which is the speed (distance over time) of the wing in the air. For example, you model for velocity at 5 m/s (meters per second).
- 5). Insert your variables and solve for the total pressure distribution. Using the assumptions above the result would be:
Pressure Distribution = (Pressure 1 - Pressure (Free Stream))/(.5 * air density * free stream velocity^2)
(500 - 450)/(.5*300* 5^2) = .013 ISA (International Standard Atmosphere)
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