6.4. Assumptions in Fluid Mechanics

Try these first

1. 1.

   What is the continuum hypothesis?

   Hint

   Think of how we view the flow of water in a river.

2. 2.

   Define stress tensor.

   Hint

   Consider forces acting within a fluid element.

3. 3.

   What does the continuum hypothesis assume about fluids?

   • They are discrete particles
   • They are continuous media
   • They cannot be analyzed mathematically

   Hint

   Consider how we analyze fluid flow in reality.

4. 4.

   True or False: Stress tensors can be used to quantify internal resistance forces in fluids.

   • True
   • False

   Hint

   Think about how these tensors help in fluid analysis.

5. 5.

   Consider a small control volume in a flowing fluid. How would you approach deriving Cauchy's equation, and what assumptions will you base this on?

   Hint

   Relate each step back to the assumptions discussed.

6. 6.

   Discuss how transitions from laminar to turbulent flows challenge the assumptions made in fluid mechanics.

   Hint

   Think about how fluid properties change with different flow regimes.