Professor Iaccarino provides a window into intriguing physical phenomena, the challenges of extreme-scale computations and simulations illustrating the fascinating beauty of fluid turbulence.

1. Beauty & the Beast
Turbulence and Computing
Gianluca Iaccarino
Joe W. Nichols & John Axerio-Cilies
Mechanical Engineering Department
Center for Turbulence Research, Stanford University
Monday, July 23, 12

2. Turbulence...the “beauty”
Monday, July 23, 12

3. Turbulence...the “beauty”
The word turbulence (from the latin word turbulentia) originally refers to
the disorderly motion of a crowd (turba). In the Middle Ages it was
frequently used to mean just "trouble", a word which derives from it.
Its scientific usage refers to irregular and seemingly chaotic motion of a fluid.
Monday, July 23, 12

4. Monday, July 23, 12

5. Monday, July 23, 12

6. Monday, July 23, 12

7. Composition VI
Wassily Kandinsky (1913)
Monday, July 23, 12

8. Turbulence...the “beauty”
The word turbulence (from the latin word turbulentia) originally refers to
the disorderly motion of a crowd (turba). In the Middle Ages it was
frequently used to mean just "trouble", a word which derives from it.
Its scientific usage refers to irregular and seemingly chaotic motion of a fluid.
Monday, July 23, 12

9. Turbulence...the “beauty”
The word turbulence (from the latin word turbulentia) originally refers to
the disorderly motion of a crowd (turba). In the Middle Ages it was
frequently used to mean just "trouble", a word which derives from it.
Its scientific usage refers to irregular and seemingly chaotic motion of a fluid.
But chaos/randomness does not completely illustrate the nature of flow
turbulence. There is structure in the chaos!
Monday, July 23, 12

10. Monday, July 23, 12

11. Monday, July 23, 12

12. Monday, July 23, 12

13. Starry Night
Vincent van Gogh (1889)
Monday, July 23, 12

14. Turbulence...the “beauty”
The word turbulence (from the latin word turbulentia) originally refers to
the disorderly motion of a crowd (turba). In the Middle Ages it was
frequently used to mean just "trouble", a word which derives from it.
Its scientific usage refers to irregular and seemingly chaotic motion of a fluid.
But chaos/randomness does not completely illustrate the nature of flow
turbulence. There is structure in the chaos!
Monday, July 23, 12

15. Turbulence...the “beauty”
The word turbulence (from the latin word turbulentia) originally refers to
the disorderly motion of a crowd (turba). In the Middle Ages it was
frequently used to mean just "trouble", a word which derives from it.
Its scientific usage refers to irregular and seemingly chaotic motion of a fluid.
But chaos/randomness does not completely illustrate the nature of flow
turbulence. There is structure in the chaos!
Another important characteristic of turbulence is the presence of multiple
scales - small eddies and large eddies
Monday, July 23, 12

16. much
thinner
than
a
human
hair
Monday, July 23, 12

17. much
thinner
than
a
human
hair
Monday, July 23, 12

18. much
thinner
than
a
human
hair
Monday, July 23, 12

19. Great Wave
Katsushika Hokusai (ca 1700)
Monday, July 23, 12

20. Turbulence...the “beauty”
The word turbulence (from the latin word turbulentia) originally refers to
the disorderly motion of a crowd (turba). In the Middle Ages it was
frequently used to mean just "trouble", a word which derives from it.
Its scientific usage refers to irregular and seemingly chaotic motion of a fluid.
But chaos/randomness does not completely illustrate the nature of flow
turbulence. There is structure in the chaos!
Another important characteristic of turbulence is the presence of multiple
scales - small eddies and large eddies
Monday, July 23, 12

21. Turbulence...the “beauty”
The word turbulence (from the latin word turbulentia) originally refers to
the disorderly motion of a crowd (turba). In the Middle Ages it was
frequently used to mean just "trouble", a word which derives from it.
Its scientific usage refers to irregular and seemingly chaotic motion of a fluid.
But chaos/randomness does not completely illustrate the nature of flow
turbulence. There is structure in the chaos!
Another important characteristic of turbulence is the presence of multiple
scales - small eddies and large eddies
The inherent beauty of turbulent motion attracts artists, but it is its inherent
complexity and ubiquitous presence that interests physicists, mathematicians
and engineers
Monday, July 23, 12

22. Studying Turbulence
Over five centuries ago Leonardo was probably the first to use the word
turbulence (in Italian turbolenza) with its modern meaning and to
observe the slow decay of eddies formed behind the pillars of a bridge.
Monday, July 23, 12

23. Studying Turbulence
Leonardo da Vinci, Codex Atlanticus (ca 1500)
areneg is auqcalled aznelobrut al euoD
ohgulp eneitnam is aucalled aznelobrut al euoD
asopiris auqcalled aznelobrut al euoD
Monday, July 23, 12

24. Studying Turbulence
Leonardo da Vinci, Codex Atlanticus (ca 1500)
areneg is auqcalled aznelobrut al euoD
ohgulp eneitnam is aucalled aznelobrut al euoD
asopiris auqcalled aznelobrut al euoD
Doue la turbolenza dellacqua si genera
Doue la turbolenza dellacua si mantiene plugho
Doue la turbolenza dellacqua siriposa
Monday, July 23, 12

25. Studying Turbulence
Leonardo da Vinci, Codex Atlanticus (ca 1500)
areneg is auqcalled aznelobrut al euoD
ohgulp eneitnam is aucalled aznelobrut al euoD
asopiris auqcalled aznelobrut al euoD
Doue la turbolenza dellacqua si genera
Doue la turbolenza dellacua si mantiene plugho
Doue la turbolenza dellacqua siriposa
Where is the turbulence in the water generated?
Where does the turbulence in the water persist for long time?
Where does the turbulence in the water come to rest?
Monday, July 23, 12

26. Studying Turbulence
The physics of turbulence has been studied extensively. using experiments.
Euler, Navier, Stokes, and later Taylor, Kolmogorov and many others built the
theoretical & mathematical foundations
Leonhard Euler George Gabriel Stokes Geoffrey Taylor Andrei Kolmogorov
1700s 1800s 1900s 1900s
Monday, July 23, 12

27. Energy spectrum
Energy
Eddy Size
Monday, July 23, 12

28. Energy spectrum
Kolmogorov
Theory
-5/3
Energy
Dissipation
into heat
Eddy Size
Monday, July 23, 12

29. Energy spectrum Where is the
turbulence in the
water generated?
Kolmogorov
Theory
-5/3
Energy
Dissipation
into heat
Eddy Size
Monday, July 23, 12

30. Energy spectrum Where is the
turbulence in the
water generated?
Kolmogorov
Theory
-5/3
Energy
Where does the
turbulence in the
water come to
rest?
Dissipation
into heat
Eddy Size
Monday, July 23, 12

31. Energy spectrum Where is the
turbulence in the
water generated?
Kolmogorov
Theory
-5/3
Energy
Where does the
turbulence in the
water come to
rest?
Dissipation
into heat
Eddy Size
Monday, July 23, 12

32. Center for Turbulence Research
Prof. William C. Reynolds
Prof. Joel H. Ferziger
Prof. Parviz Moin
1987
Monday, July 23, 12

33. Computer Simulations @ CTR
1970 1980 1990 2000 2010
Monday, July 23, 12

34. Computer Simulations @ CTR
Illiac IV
64 CPUs, 15Mflops,
$33M (1972)
Turbulent Flow
in a Channel
1970 1980 1990 2000 2010
Monday, July 23, 12

35. Computer Simulations @ CTR
Cray YMP
Complex Flow
16CPUs, 1Gflops,
$5M (1988)
1970 1980 1990 2000 2010
Monday, July 23, 12

36. Computer Simulations @ CTR
Cray YMP
Complex Flow
16CPUs, 1Gflops,
$5M (1988)
1970 1980 1990 2000 2010
Monday, July 23, 12

37. Computer Simulations @ CTR
ASCI White/IBM
8KCPUs, 5Tflops,
$10M (2000)
Turbulent Flames
1970 1980 1990 2000 2010
Monday, July 23, 12

38. Computer Simulations @ CTR
BGL-P
100KCPUs, 200Tflops,
$70M (2005)
End-to-End Aircraft
Jet Engine
1970 1980 1990 2000 2010
Monday, July 23, 12

39. Computing Power
Illiac IV BGL-P BGL-P
64 CPUs, 15Mflops, 100KCPUs, 200Tflops,
$33M (1972) $70M (2005)
Monday, July 23, 12

40. Computing Power
Illiac IV BGL-P BGL-P
64 CPUs, 15Mflops, 100KCPUs, 200Tflops,
$33M (1972) $70M (2005)
iphone 4
1CPU, 36Mflops,
$200 (2010)
Monday, July 23, 12

41. Computing Power
Illiac IV BGL-P BGL-P
64 CPUs, 15Mflops, 100KCPUs, 200Tflops,
$33M (1972) $70M (2005)
iphone 4
sequoia
1CPU, 36Mflops,
1.57MCPUs, 16.2Pflops,
$200 (2010)
$? (2012)
Monday, July 23, 12

42. Slow Down a Formula 1 Car
John Axerio Cilies
Quieting A Jet
Joe Nichols
A New Planet in 7 Days
Gianluca Iaccarino
Monday, July 23, 12

43. A Project sponsored by
Toyota Motor Corporation
Motor Sport Division
Slow Down a Formula 1 Car
John Axerio Cilies
Monday, July 23, 12

44. A Project sponsored by
Toyota Motor Corporation
Motor Sport Division
Monday, July 23, 12

45. A Project sponsored by
Toyota Motor Corporation
Motor Sport Division
Brake Cooling...
Monday, July 23, 12

46. • Brake pads are air cooled and temperature is controlled
• Flow through the tire has an impact on the wake dynamics
Flow
in
Flow out
Monday, July 23, 12

47. Monday, July 23, 12

48. Monday, July 23, 12

49. Monday, July 23, 12

50. Through-­‐Hub
Flow
Passages
Section view looking vertically
upwards from contact patch
Monday, July 23, 12

51. Through-­‐Hub
Flow
Passages
Section view looking vertically
upwards from contact patch
Monday, July 23, 12

52. Impact
of
Through-­‐Hub
Flow
CI CII
D
A
A B
Monday, July 23, 12

53. Impact
of
Through-­‐Hub
Flow
CI CII
D
A
A B
CIII
A B
Monday, July 23, 12

54. Impact
of
Through-­‐Hub
Flow
CI CII
D
A
A B
CIII CIV
A
A B
Monday, July 23, 12

55. Experimental
ValidaBon
of
Through-­‐Hub
Flow
12%
decrease
in
drag
with
op3mal
choice
of
fairing!
Monday, July 23, 12

56. Baseline Design
Drag
Brake Cooling Efficiency
Monday, July 23, 12

57. Design with Maximum Cooling
Drag
Brake Cooling Efficiency
Monday, July 23, 12

58. Design with Minimum Drag
Drag
Brake Cooling Efficiency
Monday, July 23, 12

59. Optimal Design
Drag
Brake Cooling Efficiency
Monday, July 23, 12

60. Design using Computations
Monday, July 23, 12

61. Quieting A Jet
Joe Nichols
Monday, July 23, 12

62. Monday, July 23, 12

63. Rectangular
nozzles
Baseline
(NA2Z) Chevron
(NA2C3)
Design
taken
from
the
“Extensible
Rectangular
Nozzle
Model
System”
(Frate
&
Bridges,
2011)
2:1
aspect
ra3o,
matching
experiment
precisely
Monday, July 23, 12

64. Flow
development
(Baseline)
Preferen7al
spreading
along
minor
axis
(Zaman,
1996)
Monday, July 23, 12

65. Flow
development
(Chevrons)
Monday, July 23, 12

66. Typical
supercomputer
usage
One
liJle
square
=
128
processors
Monday, July 23, 12

67. Full
system
run
(163,840
cores)
Monday, July 23, 12

68. Flow
and
noise
visualizaBon
FWH FWH
LES LES
Baseline
(NA2Z) Chevrons
(NA2C3)
Monday, July 23, 12

69. Effect
of
chevrons
Upstream Downstream
baseline baseline
chevrons chevrons
Chevrons
have
two
(good)
effects
on
noise:
1.Reduc3on
of
shock-­‐associated
noise
(upstream)
2.Reduc3on
of
turbulent
mixing
noise
(downstream)
Monday, July 23, 12

70. a new planet in 7 Days
Alan Wray, Javier Jimenez, Parviz Moin, Ali Mani, Lee
Shunn, Frank Ham, Gianluca Iaccarino
Monday, July 23, 12

71. BlueGene/L
• DOE/IBM supercomputer at LLNL
• Installation Year: 2005
• #1 on Top 500 list: 280 TFLOPS
• Theoretical peak: 370 TFLOPS
• Compute nodes: 65536 (131072 CPUs)
• I/O nodes: 1024
• Memory: 32768 GB
Monday, July 23, 12

72. Keplerian turbulence
• Protoplanetary disks need to be turbulent to
form planets
• Simplest model is rotating, sheared box of
turbulence
x2
Ω
x1
x3
Monday, July 23, 12

73. Computations
Simulations
• Grid size: 8192x2048x2048 ~ 34 billion grid points
• Ran on 65536 CPUs (half of the machine)
• 10-20 Mhours/CPU
• FFT transforms require large data (full volume)
communication multiple times per time-step
Data processing
• Each saved data field: 384 GB
• Inverse FFT on entire dataset
must be performed to visualize
solution in physical space
Monday, July 23, 12

74. Range of scales
Monday, July 23, 12

75. Energy spectrum
not all eddies are dying!
Low-Ro (fast rotation)
Monday, July 23, 12

76. Conclusions
• 7 days on BGL and still no planet
• Now we know what to look for and where
Monday, July 23, 12

77. Conclusions
• 7 days on BGL and still no planet
• Now we know what to look for and where
Monday, July 23, 12

78. center for turbulence research
Parviz Moin
Gianluca Iaccarino
Joe. W. Nichols
John Axerio-Cilies
Frank Ham
Heinz Pitsch
Marcus Herrmann
Thank You Turbulence & Computing
Beauty and the Beast
Monday, July 23, 12