Pressure force on a control volume

AI Thread Summary
The pressure forces p1 and p2 act in the same direction because both are exerting force on the fluid within the control volume. The pressure at the top pushes fluid into the control volume, while the pressure at the bottom prevents fluid from exiting. This results in both pressures contributing to the net force directed into the control volume. Understanding this concept is crucial for analyzing fluid dynamics in control volumes. The discussion emphasizes the importance of recognizing how external pressures interact with internal fluid movement.
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Homework Statement


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Why do the pressure forces due to p1 and p2 act in the same direction?

Homework Equations

The Attempt at a Solution


I thought that, given the direction of the flow, the pressure force on the bottom and top would act in opposite directions
 
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The region outside the control volume exerts a pressure force on the region inside the control volume at two locations. The pressure at the top is pushing the fluid into the control volume. The pressure at the bottom is trying to keep the fluid from coming out of the control volume. Both these pressures act in the same direction (from outside the control volume to inside the control volume).

Chet
 

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