Pipe Pressure

jan2905

A fluid of density (rho) flows through a horizontal pipe with negligible viscosity. The flow is streamline with constant flow rate. The diameter of the pipe at Point 1 is d and the flow speed is v. If the diameter of the pipe at Point 2 is d/3, then the pressure at Point 2 is?



Bournalli's Equation (sp). I ended up getting P2=P1 - 40(rho)v^2. Correct?

nvn

jan2905: That is correct; p2 = p1 - 40*rho*v^2.

jan2905

would this mean that if i were hit with the liquid at the respective points....

p1 would hurt more than p2? that would mean that a large mouth waterhose has more force than a small mouth.... that is not correct though.

nvn

jan2905: I think water exiting a small-mouth water hose at point 2 would probably hurt more, because it has a much higher velocity than the water at point 1. Both streams would be at atmospheric pressure immediately upon exit from the nozzle.

jan2905

but we deduced that p1 would have more pressure therefore hurting more. this math seems to be counterintuitive.