# Fluid Mechanics of the Golf Dimple

Μηχανική

24 Οκτ 2013 (πριν από 4 χρόνια και 6 μήνες)

106 εμφανίσεις

Fluid Mechanics of the Golf
Dimple

Nathan Kirwen

DRAG =

the force that resists the movement of a
solid

object through a
fluid

(a
liquid

or
gas
).

LAMINAR FLOW =

when the air flow is in a
smooth stream (front of ball).

TURBULANT FLOW =

when the air flow acts in
random three dimensional directions, where the drag
is created (behind ball in “wake”).

Equations Used

DRAG FORCE
( Figure 11
-
36 pg 586)

REYNOLDS NUMBER

( @ 15 C ) Table A
-
9

VARIABLES

Nike Sasquach Driver

M = 200 g

Nike ONE Golf Ball

m = 46 g

Elasticity of Golf Ball

e = 0.70

Tiger Woods Swing Speed

V = 58.1 m/s

Velocity of Ball =
(M)(V)(1 + e)

(M + m)

Velocity of Ball = 80.3 m/s

FINDING REYNOLDS NUMBER

Re =
pVD

u

p = density of fluid = 1.225 kg/m^3

V = velocity of ball = 80.3 m/s

D = diameter of ball = 4.27 x 10^
-
2 m

u = viscosity of fluid = 1.802 x 10^
-
5 kg/(m)(s)

Re = 2.39 x 10^5

FINDING COEFFICIENT OF
DRAG

Reynolds Number

Re = 2.39 x 10^5

Use Reynolds Number to Find Cd

Use Figure 11
-
36 on pg. 586

Cd = approx. 0.25

FINDING DRAG FORCE

Drag Force = (1/2)(Cd)(A)(p)(V^2)

Cd = Coeff. of Drag = 0.25 (0.51 Smooth)

A = Surface Area =
1.43 x 10^
-
3 m^2

p = Density of Fluid = 1.225 kg/m^3

V = Velocity of Ball = 80.3 m/s

Drag Force (Dimpled) = 1.41 N

Drag Force (Smooth) = 2.88 N

REFERENCES

http://www.tournamentshowroom.com/images/products/Logo
-
Golf
-
Balls/LGB80
-
L.jpg

http://www.doubleeaglegolfmemphis.com/productimages/NIKE461.jpg

http://www.geo.mtu.edu/volcanoes/vc_web/background/graphics/reynold.gif

http://web.mit.edu/12.000/www/m2005/a2/finalwebsite/equipment/manned/equat
ion1.gif

http://ffden2.phys.uaf.edu/211_fall2002.web.dir/Randolph_Bailey/Web%20Proje
ct/Tiger.html

http://www.vu.union.edu/~scottg/Senior_Project/Theory%20and%20Analysis.ht
ml

http://www.livescience.com/images/061020_golf_ball_03.jpg