Calculating Water Pressure from Speed: A Scientific Approach

[zeroonezero]

How do you calculate the pressure exerted by water if you know the speed?

 

[Yuqing]

Its difficult to say without knowing more, but you might try

http://en.wikipedia.org/wiki/Bernoulli%27s_principle"

 

[zeroonezero]

What I really should have asked was: Since I calculate the pressure applied by a given wind speed by the following simple method:- Mph^2 * 0.0027 = psf so, is there a simple method to calculate the pressure applied by a given water speed? Thanks

 

[cjl]

If all you want to know is the dynamic pressure, then you can find it for any incompressible fluid (which includes most gases, so long as the speed in question is below about mach 0.3) by simply using the equation P = 1/2ρv².

 

[zeroonezero]

Pardon my ignorance...the only thing I know is the speed of the water...6 knots...I have a plate 3ft sq facing that flow...How do I calculate the pressure on that plate, or any plate, in terms of psi or psf? P=1/2pv2 does not make sense to me since P, p is pressure

 

[SteamKing]

If all you want to know is the dynamic pressure, then you can find it for any incompressible fluid (which includes most gases, so long as the speed in question is below about mach 0.3) by simply using the equation P = 1/2ρv².

In the formula above, the stagnation pressure P is a function of the density of the water (little p) and the velocity of the water. What you have to do is convert the velocity of the water from knots to units you can use with density in order to calculate the pressure P. If you use velocity in feet per second, for example, the density of the water must be in slugs per cubic foot. The resulting pressure will be in pounds per square foot.

 

[cjl]

Pardon my ignorance...the only thing I know is the speed of the water...6 knots...I have a plate 3ft sq facing that flow...How do I calculate the pressure on that plate, or any plate, in terms of psi or psf? P=1/2pv2 does not make sense to me since P, p is pressure

In the equation P = 1/2ρv², the ρ is not a p (see the difference?). It's a greek letter rho, which is the density of the fluid. As SteamKing said, you'll need to use consistent units in order for the answer to be correct.

 

[zeroonezero]

Oops! Did not catch that...Thanks...