Confused with static pressure and total pressure and Bernoulli's eq!


by degredationz
Tags: bernoulli, confused, pressure, static
degredationz
degredationz is offline
#1
Sep1-08, 11:29 PM
P: 6
hi all, am a confused-being after trying to solve this really simple question..
somewhere somehow my concepts are just not right ):

Consider an airplane flying with a velocity of 60m/s at a standard altitude of 3km. At a point on the wing, the airflow velocity is 70m/s. Calculate the pressure at this point.

By using p1+1/2(rou)(v1)^2=p2+1/2(rou)(v2)^2 and the standard atmospheric pressure table, the given solution is
7.0121 X 10^4 + 1/2(9.0926X10^(-1))(60^2)/2 = P2 + 9.0926X10^(-1)(70^2)/2
I do not understand why P1 = 7.0121 x 10^4 N (given in the table), where P1 should be the pressure at the point of the flow where velocity is 60m/s.
What is the pressure given in the table referred to as?
I am confused with static/dynamic and total pressure!

Would any kind soul please help?
Thanks alot in advance!
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Cyrus
Cyrus is offline
#2
Sep1-08, 11:53 PM
Cyrus's Avatar
P: 4,780
http://en.wikipedia.org/wiki/Static_pressure

http://en.wikipedia.org/wiki/Dynamic_pressure

P1 = 7.0121 x 10^4 N is the static (atmospheric) pressure at an altitude of 3km.


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