3. 161 Year Old Tradition
1851 ! ! Royal Yacht Squadron gives cup for Isle of Wight race!
! ! Won by schooner America, donated to New York Yacht Club!!
! ! !
! ! Deed of Gift: cup for perpetual international competition!
till 1970 !Twenty successful defenses with always just one challenger!
!
1970 ! !Challenger selection series starts – the Louis Vuitton Cup!
!
1983 ! !Royal Perth Yacht Club steals trophy from NYYC (finally!)!
!
1987 ! !Dennis Connor (USA) takes revenge in Stars & Stripes in Perth!
!
1988 ! ! Surprise challenge by New Zealand (KZ1 90 ft "big boat")!
! ! Connor won with 45 ft cat. !
!
4. !
! ! !!
1992 ! !US successfully defends Cup in San Diego!
!
1995 ! !Team New Zealand sails to victory in San Diego!
!
2000 ! !Team New Zealand beats Italian challenger Prada!
!
2003 ! !Swiss challenger Alinghi beats Team New Zealand in Auckland!
!
2007 ! !Alinghi beats challenger Team New Zealand in Valencia!
!
2008-9! ! Team Oracle wins court case for rightful AC challenge!
! ! (Battle of the Billionaires Ellison and Bertarelli)!
!
!
!
2010 ! !Oracle beats Alinghi in Valencia!
5. 115ft long!
!
Swiss Alinghi skipper!
Brad Butterworth!
!
USA Oracle skipper!
Jimmy Spithill!
Captain Russell Coutts!
!
!
Oracle easily beats Alinghi
with metallic wing rather
than traditional sail!
!
!
!
!
6. America’s Cup World Series AC45
Wingsail catamaran by!
Mike Drummond/Oracle !
honeycombcore/carbonfiber!
44 ft; 2850 lb; 70 ft heigh!
!
!
7. 2013 America’s Cup (number 34)
America’s Cup World Series !
Regular circuit of regattas with fleet and match racing in each event!
2011-2012 !completed!
2012-2013 !San Francisco, Aug 21-26 and Oct 2-7, 2012!
! ! !Venice, April 16-21, 2013!
! ! !Naples, May 14-19, 2013!
! ! !!
!
Louis Vuitton Cup !San Francisco, July 4 – Sept 1, 2013!
!
America’s Cup Finals !San Francisco, Sept 7 – 22, 2013!
!
11. Typically *very* close races
Time! Delta in !
Min:sec! seconds!
Start! 0!
1! 26:11! 12!
2! 24:14! -34!
3! 26:37! -26!
4! 22:43! -14! Three upwind, three downwind legs!
5! 27:33! -26! Each 3 nautical miles!
!
finish! 25:43! 7!
12. How to Maximize Performance?
Can Mathematics Help?
Balance forces and moments and maintain stability!
Make sure structural design limits are met!
Respect any race and design rules !
Take into account uncertainty in wind, waves and crew handling!
! !!
A *very* complex engineering problem!!!
!
13. The Main Design Rule in 2000/2003
( length + 1.25 x (sail area)1/2 – 9.8 x (displacement)1/3 ) / 0.679 = 24!
The international America’s Cup Class Rule!
!
Originally hoped to introduce difference designs!
!
!
But, two typical designs:!
!
Length overall !82 ft ! !79.5 ft!
Beam ! !14.1 ! !13.3 ft!
Sail area! !3600 sq ft !3600 sq ft!
!
!
15. Heeling force limits max driving force
Vertical plane
aerodynamic
side foce
heel angle
crew
weight
Stability through crew,!
lead ballast in lower!
part keel and/or bulb!
!
In IACC, bulb is 20!
hydrodynamic buoyancy force
weight
tons out of total of 24!
side force
22. 3D adds a Literal Twist
Angle and strength apparent wind varies with height!
UT
Twisted onset flow!
US UA
Sails twisted!
(to operate close to ideal angle)!
!
!
23. Wind tunnels in sail design
University of Auckland !
Twisted Flow Wind Tunnel!
24. CFD only option for upwind analysis
Flat sail (small camber)!
Possibly TE separation, LE bubble (re-attached)!
!
For AC upwind main+genoa!
• Re O(106), L/D approximately 8-9!
• Pressure drag approximately 10% of sail drag!
• Induced drag up to 15% of total drag (high roach)!
25. Resolve Turbulent Flow Features
> ideal (22º)
Ideal angle (18º)
> ideal (26º)!
Choice turbulence models non-trivial when separated!
26. Downwind CFD in Early Stage
Wind tunnel tests lead to 15% efficiency gain !
What improvement can we get with CFD?!
!
AC genneker operates at maximum lift (high-lift foil)!