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Physics: Wind and Javelin, what’s the verdict?

Submitted by on March 28, 2009 – 2:52 pmNo Comment | 3,833 views

Head wind, tail wind, cross from the right, cross from the left; what’s the verdict?

There is often much dispute about which direction of wind will provide the most benefit to the javelin. At most tracks, there is the option to throw from at least two different javelin sectors. In a blistering crosswind, which direction of wind is the most beneficial? In this article we will discuss current evidence.

Science: Les Hatton from the Faculty of Computing, Information Systems and Mathematics at the University of Kingston published a paper titled “Optimising the javelin throw in the presence of prevailing winds” [1], which was updated on January 28, 2007.  The mathematical model is based and calibrated on data from various championships’ results. It is a very sophisticated model, which “solves a coupled non-linear set of ordinary differential equations that incorporate the full three-dimensional effects of lift, drag and rotation” of the javelin throw. Using the Javelin Flight Analyser software based on this model, the following results provide an idea of the effect of wind on distance.
Table 1. Wind Direction

Wind Direction (°)

Distance (m)

0 = Head wind

56.87

64.00

65.3

66.66

45 = Right Head

58.87

66.1

67.38

68.17

90 = Right Cross

63.9

71.21

72.4

73.62

135 = Right Tail

69.15

76.33

77.4

78.47

180 = Tail wind

71.39

78.46

79.46

80.48

225 = Left Tail

69.12

76.3

77.36

78.44

270 = Left Cross

63.82

71.1

72.3

73.51

315 = Left Head

58.84

66.06

67.34

68.66

No Wind

63.94

71.26

72.45

73.67

Attack Angle (°)

0

-5

0

5

Release Angle (°)

30

40

40

40

Constant: Javelin = Tailwind, Weight = 800g, Wind Speed = 2.0 m/s, Release Velocity = 26 m/s

Conclusion: From the table above you can see that any tailwind is beneficial, and a wind from the right (for a right handed thrower) is slightly advantageous. Of course there are limitations to this model as described by Hatton in his paper, however this result agrees with first principles that a wind which opposes the direction of the javelin’s flight will increase the drag, and therefore decrease its speed. We know that the speed of the javelin is the most important factor for a long throw.
References:
1. Hatton, Les. Optimising the javelin throw in the presence of prevailing winds. University of Kingston, January 28, 2007. http://www.leshatton.org/javelin_2005.html [Accessed 10 November 2010].

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