Question

1. You explored the effect of flow rate of water in response to changes in tube diameter.

Did your prediction of the what tube would give the fastest and slowest flow rate turn out to be correct after performing the experiment? If not, why were you surprised? (if you have not performed the experiment, make a prediction based on what you learned in the lecture how flow rate is affected by the radius of a tube and then watch the video of the experiment on vUWS labelled bucket_flow rate).

What implications could this important concept and physics principal have in “real life” applications – list as many as you can think of where this concept applies or is used.

What implications does this important concept have in physiology?

What other physical characteristic of a fluid would influence the flow of a bodily liquid such as blood? How would it influence flow and why?

Answer 1

The volume flow rate of water or any liquid flowing out per second through a horizontal pipe or capillary was given by Poiseuille. Poiseuille's formula is given asAccording to the above mentioned formula, when length of pipe and viscosity of liquid is small then flow is faster and vice versa. Flow rate is also depending directly on pressure gradient across the tube and radius of the tube. Almost same result is obtained through the experiment.

Applications:

(I) It is applied to flow of air and medicine through a syringe.

(Il) Air flow through a drinking straw

(III) Air flow in lungs alveoli

(IV) flow of water through a capillary or narrow pipe.

In physiology it is well applied to the flow of blood through arteries and veins. In arteries viscosity of blood creates an additional pressure drop.