Large-Diameter Hose and Small-Diameter Hose

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What kind of experiment is this?

Experimental procedure and explanation:

• We drain water from a tank using the siphon principle and study how the flow speed varies with the diameter of the hose.
• When a large-diameter hose (9-mm inner diameter) is used, the water flows smoothly.
• When small-diameter hoses (ten hoses, each with 3-mm inner diameter) are used, the flow speed reduces. The overall cross-sectional area of the ten hoses is larger than that of the single 9-mm inner diameter hose, but the flow is slower.
• When a fluid (liquid or gas) flows through a tube, viscous friction acts between the inner walls of the tube and the fluid, due to the viscosity of the fluid. This friction causes resistance to the fluid flow. The resultant loss of fluid energy is called pipe friction loss.
• For hoses having the same lengths and the same flow speeds, pipe friction is inversely proportional to tube diameter. Therefore, in this experiment, the resistance for the smaller diameter hose is larger, thereby reducing the flow speed.
• When a fluid flows through a tube, energy losses can be reduced by avoiding the use of small-diameter tubes and using large-diameter tubes.

[Keywords]	Pipe friction loss
[Related items]	Short Hose and Long Hose
[Reference]	“The Wonders of Flow,” Japan Society of Mechanical Engineering, Kodansha Blue Backs pp. 182–185. “Illustrated Fluid Dynamics Trivia,” by Ryozo Ishiwata, Natsume Publishing, pp. 180–181.