Fluid Mechanics, Linear Momentum Example Problem with a stationary control volume, with step by step walkthrough for how to find the force on a pipe bend due to fluid entering or leaving the control volume.

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To find the force on a pipe elbow, you could use the Reynold's Transport Theorem version of the Conservation of Linear Momentum, or my recommendation, you can more simply apply free body diagrams and kinetic diagrams to solve this fluid momentum problem operating at steady state.

Most important takeaways I hope you learn are the sign convention for fluid entering or leaving the control volume, based on the dot product, and also after you draw the control volume, not to forget to apply gage pressure at each inlet or outlet as a force acting on the CV at that location.


TIMECODES
0:00 Reynold's Transport Theorem
0:46 Draw the Control Volume
1:26 Draw the Free Body Diagram and Kinetic Diagram
4:18 Equilibrium Equations
4:45 Sign Convention
8:40 Find Mass Flow Rate
9:46 Plug n Chug
12:10 Final Answers