ALEXANDRIA UNIVERSITY,

FACULATY OF ENGINEERING,

MECHANICAL DEPARTMENT.

Lift & Drag

Applications in the Olympic Games

* Contents:-

*Introduction

*Applications of lift and drag in Olympic games:-

1- swimming.

2-Javelin throw.

3-Cycling.

* Our dream in Olympic games.

* References

Introduction:-

*Aerodynamic forces are important in

many racing sports and all those which

use projectiles.

*Sport is a science.

1-Swimming:-

* Which countries are distinguished in this game ?

1-1-Forces against the swimmer:-

*Skin friction: which is analogous to the "stickiness" of the

swimmer for moving through the water;

*Eddy resistance (Form drag): the amount of water that is

sucked along behind a swimmer as forward progression is

achieved and is proportional to the cross-sectional area

that is pushed against the water.

*Wave-making resistance: which is caused by swimmers'

movements that move large amounts of water (e.g., excessive diving of the shoulders and body at the butterfly entry).

1-2-Forces with the swimmer:-

*Propulsion:- The hand follows a curvilinear path to

continuously find still water to push against and thus gain

more resistance than it would by pushing against water

that had already been accelerated.

*Lift is important for propulsion:- For an optimal

propulsive force, the orientation of the hand must be

constantly fitted to ever changing directions of hand

movement during the pull. In order to select the angle

of attack which gives the optimal combination of drag

and lift forces at every moment of a pull.

*Finger Spacing effect on propulsion:-

1-3-Ways to decrease resistance on body:-

2- Javelin throw:-

* Which countries are distinguished in this game ?

Javelin throw

Drag and lift forces

The attack

angle

Javelin types

2-1- Drag and lift forces :-

The two important points in a javelin are the center of gravity, where the mass acts and the center of pressure where the less tangible aerodynamic forces of drag and lift act.

اللعيبة ابن يا

2-2- The angle of attack:-

*The angle of attack represents the difference between the path of the javelin and the path of the throwing hand.

*Some of the best throwers in the world would throw the javelin with as little as 30 degree angle.

*The most common method is releasing the javelin at about a 40 degree angle, causing more lift and flight to the javelin.

2-3- The headwinds and tailwinds javelins:-

Dick Held simply said to use the Tailwind javelin for tailwinds. In truth, he knew that the Tailwind javelin out performed the Headwind javelin in effectively all winds.

3-Cycling:-

* Which countries are distinguished in this game ?

Our dream in Olympic games:-

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