19.7.1. Understanding Reynolds Numbers

Try these first

1. 1.

   What is the formula to calculate Reynolds number?

   Hint

   Look for the relationship between inertia and viscous forces.

2. 2.

   If a fluid has a Reynolds number of 1500, what type of flow is it?

   Hint

   Remember the threshold values for laminar and turbulent flow.

3. 3.

   What happens to the flow when the Reynolds number exceeds 4000?

   • It remains laminar.
   • It becomes turbulent.
   • It becomes transitional.

   Hint

   Consider the classification of flows based on Reynolds number thresholds.

4. 4.

   Is the statement true or false: A Reynolds number of less than 2300 indicates turbulent flow.

   • True
   • False

   Hint

   Review the threshold definitions provided.

5. 5.

   For a fluid with a density of 850 kg/m³ and dynamic viscosity of 0.002 Pa.s flowing at a velocity of 1.5 m/s in a pipe with a diameter of 0.1 m, calculate the Reynolds number and state the flow regime.

   Hint

   Substitute the values carefully in the formula and remember the definitions.

6. 6.

   Discuss how varying the diameter of a pipe in a water supply system affects the Reynolds number and potential flow regimes encountered.

   Hint

   Think about the equations you've learned regarding diameter and flow.