How swim caps and suits reduce drag and increase swimmer velocity

Physics of Swimming

Streamlining "drag" effects a swimmer performance speed. Key words Friction a solid a fluid. Viscosity - density liquid. Drag forces Impulse related momentum. I trials a swimmer starting a suit, suit cap (hair creates drag), added a piece clothing swimmer trial show weight, drag slows swimmer .

Physics of Swimming

The physics of swimming

The density of water is 1000 times higher than density of air. Therefore, water is more resistant than air. Buoyancy is the force which acts on the swimmer upwardly, this is because pressure increases with water depth Toussaint, Hollander, van der Berg, & Vorontsov, 2000()

The weight of the water needs to be less or equal to the buoyant force in order for an object to float and therefore, the more buoyant a swimmer is the more advantageous he is.

For a swimmer to float, the pressure under him should be greater than the pressure above him, because air is less resistant than fluid a swimmer faces the least resistance when at the surface. By resistance, we mean opposition, this resistance of fluids, (in this case water) is referred to as Viscosity Toussaint et al., 2000.

In that case, a person's energy is lost through drag thus the need for swimmers to make very good use of their streamline to make the surface area of a person going through water smaller. Resistance and drag will reduce due to the reduced surface area Toussaint, Roos, & Kolmogorov, 2004.

Therefore, it is important to reduce the surface area as much as possible in order to achieve maximum velocity.

A swimmer will do several things in order to achieve a smaller surface area he will wear a swim suit and a swim cap. In order to reduce drag on the head surface, swimmers wear swim caps. Swim suits and swim caps are more effective in achieving a smaller surface area than shaving a swimmers whole body, this is because they are smoother than a shaved flesh Toussaint et al., 2004.

A swimmers body covered in a swim suit and a swim cap faces less resistance from water thus achieving velocity due to the reduced viscosity.

Factors affecting a swimmers velocity

Viscosity

Viscosity refers to the property that makes stirring syrup cumbersome. It essentially means the frictional force present in different water layers as they replace each other. The water layer directly in contact with the swimmer moves at the same speed as the swimmer Toussaint et al., 2000.

Water layers that are further away from the swimmer's body have a lower speed. This speed decreases as it moves further away from the body surface. The water surface away from the swimmers body will retard that layer closer to the swimmer's body thus creation a drag. The force exerted to retard the water closer to the swimmer's body is proportional to the surface area of the swimmer. In essence, the swimmer uses a swim suit to reduce their surface area and thus the drag caused by water layer replacements.

Swim Cap

Hair increases the hydrodynamic drag, this makes it necessary for a swimmer to use a swim cap. The swimming cap reduces the hydrodynamic drag while a person is swimming, this is done by the fact that the head becomes a surface so smooth where water swiftly flows thus reducing the viscosity and achieving speed Toussaint et al., 2000()

Surface Area

The larger the surface area of a body, the less the speed a body can move in water. This is because of the resistance created by the larger body's surface area. This makes it essential for the swimmer to reduce his body's surface area in order to achieve speed Toussaint et al., 2000.

Tightening the body such that it resembles a torpedo is done to minimize the surface area. Each movement in water by a swimmer reduces a swimmer's strength and efficiency. Power and resistance increase by cubes or squares at times, so in order to achieve 10% speed increment, the loss of energy due to swimming would by 30% and therefore, need to maximally reduced the surface area in order to achieve speed.

Drag Force

Drag is the opposing force that water gives to a swimmer's body as he is swimming and it is onerous to swimmers. In order to achieve maximum speed, a swimmer needs to reduce drag as much as possible. There are three main forces of drag that affect a swimmer, these include pressure, friction and wave drag. The increased speed of a swimmer causes pressure drag thus hampering forward movement. The frictional drag is brought about by a swimmer's body continually rubbing against water molecules. However, it is beneficial because it propels the swimmer forward. At racing speeds, an increase of pressure is created around a swimmer's body, causing waves which try to slow down the swimmer's speed. The factors that affect the drag force are the swimmer's body size and shape, the swimmer's skill (alignment) and the swimmer's body length. The drag force increase is directly proportional to the velocity squared. Toussaint et al. (2004)

found out that rotating the hips powerfully reduces drag by radiating this power to the entire body.