- #1
Ma77h3w
- 7
- 0
Confusion... I'm probably being stupid but...
Aerofoil in a wind tunnel... there are lots of pressure tappings including Pt and Ps (static and total pressure freestream) these are currently in mm on a manometer..
my Pt is 11.4mm and Ps is 16.8mm.. (SG=0.8)
1st question: Should total pressure be less than static? because i can't solve the equation to find free stream velocity.. rearranging: Pt - Ps = 1/2 p V^2 (p = density)
as Pt - Ps is negative.. hence finding V is impossible.. can't root a negative. Have i mixed the two up?
however my Cp against x/c graph looks good.. and swapping Pt and Ps messes it up..
Thanks
Aerofoil in a wind tunnel... there are lots of pressure tappings including Pt and Ps (static and total pressure freestream) these are currently in mm on a manometer..
my Pt is 11.4mm and Ps is 16.8mm.. (SG=0.8)
1st question: Should total pressure be less than static? because i can't solve the equation to find free stream velocity.. rearranging: Pt - Ps = 1/2 p V^2 (p = density)
as Pt - Ps is negative.. hence finding V is impossible.. can't root a negative. Have i mixed the two up?
however my Cp against x/c graph looks good.. and swapping Pt and Ps messes it up..
Thanks