Pressure to Achieve 10 m/s Flow Into Underwater Reservoir

[ACE_99]

Homework Statement

What pressure Pr, is required to achieve a flow rate of 10 m/s into the underwater reservoir if the tank is 100 m below the surface. Liquid ammonia is to be transferred with a density of 682 kg/m^3 and the pipe diameter is 5 cm. The reservoir underwater is at local hydrostatic pressure. A picture is included.

Homework Equations

Bernoulli's Eqn: P1 + (1/2)\rhoU² +\rhogz

The Attempt at a Solution

At first I thought that it was as simple as plugging in the values given into the formula and solving for P1, but then I realized that they gave us the diameter of the pipe too so I'm guessing it has some significance. I can't seem to figure it out though, any help would be great.

http://i429.photobucket.com/albums/qq12/ACE_99_photo/Untitled-2.jpg"

 

[Q_Goest]

Hi Ace. Bernoulli's equation is just one of the necessary equations to calculate this. The other is the irreversible pressure drop of fluid that flows through a pipe which is best done using the Darcy Weisbach equation. You can plug the DW equation into the B equation simply by recognizing that there is a permenant pressure drop under flow equal to the pressure predicted by the DW equation.

Take a look at the DW equation and try to understand how the flow of fluid corresponds to some pressure drop in a pipe.