19.1.3. Surface Force Acting on a Differential Surface Element

Try these first

1. 1.

   Define the term 'Stress Tensor'.

   Hint

   Think about how stress is defined in terms of force.

2. 2.

   What is the significance of normal stress?

   Hint

   Consider its action on a surface.

3. 3.

   What does the stress tensor represent in fluid mechanics?

   • Only normal stress
   • Both normal and shear stress
   • Only shear stress

   Hint

   Recall the components of the tensor.

4. 4.

   True or False: Shear stress acts perpendicular to a surface.

   • True
   • False

   Hint

   Visualize the action direction of shear stress.

5. 5.

   A cylindrical tank filled with water experiences an increase in internal pressure causing stress in the tank walls. Calculate the normal and shear stresses along a horizontal cross-section of the tank if the internal pressure is known.

   Hint

   Start by identifying the key stress components from pressure data.

6. 6.

   In a particular engineering application, the shear stress from viscosity dominates the forces acting on a fluid element. How would you analyze this using control volume concepts?

   Hint

   Examine the relationships between shear rate and viscosity to evaluate stress appropriately.