# Calculating Water Pressure from Speed: A Scientific Approach

• zeroonezero
In summary, to calculate the pressure exerted by water, you can use the equation P = 1/2ρv2, where ρ is the density of the water and v is the velocity. Make sure to use consistent units for accurate results.
zeroonezero
How do you calculate the pressure exerted by water if you know the speed?

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

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

Last edited by a moderator:
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

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.

Hesham Youssef
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

cjl said:
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.

zeroonezero said:
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.

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

## What is pressure and speed of water?

Pressure is the force exerted by water on a surface, while speed is the rate at which water moves through a space.

## How are pressure and speed of water related?

As the speed of water increases, the pressure it exerts also increases. This is due to the kinetic energy of the moving water molecules.

## What factors affect the pressure and speed of water?

The viscosity, density, and temperature of water can all affect its pressure and speed. Additionally, the shape and size of the space through which the water is moving can also impact these factors.

## How is pressure and speed of water measured?

Pressure is typically measured in units of force per unit area, such as pounds per square inch (psi) or pascals (Pa). Speed can be measured in units of distance per unit time, such as meters per second (m/s) or feet per second (ft/s).

## Why is understanding pressure and speed of water important?

Understanding pressure and speed of water is crucial for various industries and fields, including hydrology, engineering, and environmental science. It can also help predict and prevent potential hazards, such as floods and erosion, caused by water movements.

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