Movement through water - Directed Task

Question 1

What are eddies and why do they slow movement through the water so much?

Answer 1

An eddy is a turbulence that occurs in the wake of an object. Eddies appear like small whirlpools of water (or air). Energy is taken from the person or object to form the eddies, hence slowing the object down.

Question 2

What profile is optimal to adopt in the water to reduce eddies?

Answer 2

The way to reduce eddies is to taper the end of the object so that the object becomes ‘streamlined.’ This shape is called an aerofoil (in air) or a hydrofoil (in water).

Question 3

How can a swimmer reduce drag forces on the body?

Answer 3

Form drag can be reduced by decreasing the frontal surface area presented to the water;

Surface drag can be reduced by removing body hair or wearing special swimsuits;

Wave drag can be reduced by swimming underwater for as long as legally allowed.