Fluid Mechanics of the Golf Dimple

stickshrivelMechanics

Oct 24, 2013 (3 years and 1 month ago)

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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