Force of Water Flow: Calculating Pressure on Structure

[smprindi]

If a pipe flowing with water enters a structure where the structure wall will stop the horizontal velocity of the flow and direct it downward (i.e a pipe into a manhole with an outlet at a considerably lower elevation), how do you calculate the force exerted on the structure of that wall. I have found the equation Force = density of water * flow volume * change in velocity. Is this on the right track?

 

[tiny-tim]

Welcome to PF!

Hi smprindi ! Welcome to PF!

… how do you calculate the force exerted on the structure of that wall. I have found the equation Force = density of water * flow volume * change in velocity. Is this on the right track?

Yes …

from good ol' Newton's second law …

force = rate of change of momentum

= velocity times mass per time …

which is the same as your Force = density of water * flow volume * change in velocity.

 

[astrokreng]

Yes, you are on the right track. To calculate the force exerted on the structure, you need to consider the change in momentum of the water as it enters the structure and changes direction. This can be calculated using the equation Force = mass flow rate * change in velocity. The mass flow rate can be calculated by multiplying the density of water by the flow volume. However, it is important to note that this equation assumes the water is incompressible and there are no losses due to friction or turbulence. In real-world situations, these factors may need to be taken into account to get a more accurate calculation of the force exerted on the structure.