15.4. Simplifications in Fluid Flow Problems

Try these first

1. 1.

   Define a fixed control volume.

   Hint

   Think of a container that does not move.

2. 2.

   What does mass conservation imply?

   Hint

   Consider how mass behaves in a closed system.

3. 3.

   What is a control volume?

   • A moving mass
   • An analytical space region for fluid analysis
   • A brine solution

   Hint

   Think about regions used for calculations.

4. 4.

   True or False: Mass can be created in an isolated system.

   • True
   • False

   Hint

   Consider fundamental principles of physics.

5. 5.

   Design a control volume for a pipe system with varying diameters. Describe how you would compute the mass flow rates at different cross-sections.

   Hint

   Focus on keeping track of different inflows and outflows in varying sections.

6. 6.

   Explain how one would approach the analysis of a spacecraft re-entering Earth's atmosphere using conservation laws.

   Hint

   Think about mass displacements and the equations you've learned about forces and motion.