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Professor Iaccarino provides a window into intriguing physical phenomena, the challenges of extreme-scale computations and simulations illustrating the fascinating beauty of fluid turbulence.
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Beauty & the BeastTurbulence and Computing
Gianluca IaccarinoJoe W. Nichols & John Axerio-CiliesMechanical Engineering DepartmentCenter for Turbulence Research, Stanford University
Monday, July 23, 12
Turbulence...the “beauty”
Monday, July 23, 12
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.
Turbulence...the “beauty”
Monday, July 23, 12
Monday, July 23, 12
Monday, July 23, 12
Monday, July 23, 12
Composition VIWassily Kandinsky (1913)
Monday, July 23, 12
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.
Turbulence...the “beauty”
Monday, July 23, 12
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.
Turbulence...the “beauty”
But chaos/randomness does not completely illustrate the nature of flow turbulence. There is structure in the chaos!
Monday, July 23, 12
Monday, July 23, 12
Monday, July 23, 12
Monday, July 23, 12
Starry NightVincent van Gogh (1889)
Monday, July 23, 12
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.
Turbulence...the “beauty”
But chaos/randomness does not completely illustrate the nature of flow turbulence. There is structure in the chaos!
Monday, July 23, 12
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.
Turbulence...the “beauty”
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
much thinner than a human hair
Monday, July 23, 12
much thinner than a human hair
Monday, July 23, 12
much thinner than a human hair
Monday, July 23, 12
Great WaveKatsushika Hokusai (ca 1700)
Monday, July 23, 12
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.
Turbulence...the “beauty”
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
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.
Turbulence...the “beauty”
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
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.
Studying Turbulence
Monday, July 23, 12
Leonardo da Vinci, Codex Atlanticus (ca 1500)
Studying Turbulence
Doue la turbolenza dellacqua si generaDoue la turbolenza dellacua si mantiene plughoDoue la turbolenza dellacqua siriposa
Monday, July 23, 12
Leonardo da Vinci, Codex Atlanticus (ca 1500)
Doue la turbolenza dellacqua si generaDoue la turbolenza dellacua si mantiene plughoDoue la turbolenza dellacqua siriposa
Studying Turbulence
Doue la turbolenza dellacqua si generaDoue la turbolenza dellacua si mantiene plughoDoue la turbolenza dellacqua siriposa
Monday, July 23, 12
Leonardo da Vinci, Codex Atlanticus (ca 1500)
Doue la turbolenza dellacqua si generaDoue la turbolenza dellacua si mantiene plughoDoue 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?
Studying Turbulence
Doue la turbolenza dellacqua si generaDoue la turbolenza dellacua si mantiene plughoDoue la turbolenza dellacqua siriposa
Monday, July 23, 12
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
Studying Turbulence
Leonhard Euler1700s
George Gabriel Stokes1800s
Andrei Kolmogorov1900s
Geoffrey Taylor1900s
Monday, July 23, 12
Ener
gy
Eddy Size
Energy spectrum
Monday, July 23, 12
Kolmogorov Theory -5/3
Ener
gy
Eddy Size
Dissipation into heat
Energy spectrum
Monday, July 23, 12
Kolmogorov Theory -5/3
Ener
gy
Eddy Size
Dissipation into heat
Where is the turbulence in the water generated?
Energy spectrum
Monday, July 23, 12
Kolmogorov Theory -5/3
Where does the turbulence in the water come to rest?
Ener
gy
Eddy Size
Dissipation into heat
Where is the turbulence in the water generated?
Energy spectrum
Monday, July 23, 12
Kolmogorov Theory -5/3
Where is the turbulence in the water generated?
Where does the turbulence in the water come to rest?
Ener
gy
Eddy Size
Dissipation into heat
Energy spectrum
Monday, July 23, 12
Center for Turbulence Research
Prof. William C. ReynoldsProf. Joel H. FerzigerProf. Parviz Moin
1987Monday, July 23, 12
Computer Simulations @ CTR
1970 1980 1990 2000 2010
Monday, July 23, 12
Computer Simulations @ CTR
1970 1980 1990 2000 2010
Turbulent Flow in a Channel
64 CPUs, 15Mflops, $33M (1972)
Illiac IV
Monday, July 23, 12
Computer Simulations @ CTR
1970 1980 1990 2000 2010
16CPUs, 1Gflops, $5M (1988)
Cray YMP
Complex Flow
Monday, July 23, 12
Computer Simulations @ CTR
1970 1980 1990 2000 2010
16CPUs, 1Gflops, $5M (1988)
Cray YMP
Complex Flow
Monday, July 23, 12
1970 1980 1990 2000 2010
8KCPUs, 5Tflops, $10M (2000)
ASCI White/IBM
Turbulent Flames
Computer Simulations @ CTR
Monday, July 23, 12
100KCPUs, 200Tflops, $70M (2005)
BGL-P
Computer Simulations @ CTR
1970 1980 1990 2000 2010
End-to-End Aircraft Jet Engine
Monday, July 23, 12
BGL-P
Computing Power
100KCPUs, 200Tflops, $70M (2005)
BGL-P
64 CPUs, 15Mflops, $33M (1972)
Illiac IV
Monday, July 23, 12
BGL-P
Computing Power
100KCPUs, 200Tflops, $70M (2005)
BGL-P
64 CPUs, 15Mflops, $33M (1972)
Illiac IV
1CPU, 36Mflops, $200 (2010)
iphone 4
Monday, July 23, 12
BGL-P
Computing Power
100KCPUs, 200Tflops, $70M (2005)
BGL-P
64 CPUs, 15Mflops, $33M (1972)
Illiac IV
1CPU, 36Mflops, $200 (2010)
iphone 4
sequoia
1.57MCPUs, 16.2Pflops, $? (2012)
Monday, July 23, 12
Quieting A JetJoe Nichols
Slow Down a Formula 1 CarJohn Axerio Cilies
A New Planet in 7 DaysGianluca Iaccarino
Monday, July 23, 12
A Project sponsored by Toyota Motor Corporation
Motor Sport Division
Slow Down a Formula 1 CarJohn Axerio Cilies
Monday, July 23, 12
A Project sponsored by Toyota Motor Corporation
Motor Sport Division
Monday, July 23, 12
A Project sponsored by Toyota Motor Corporation
Motor Sport Division
Brake Cooling...
Monday, July 23, 12
• Brake pads are air cooled and temperature is controlled• Flow through the tire has an impact on the wake dynamics
Flowin
Flow out
Monday, July 23, 12
Monday, July 23, 12
Monday, July 23, 12
Monday, July 23, 12
Section view looking vertically upwards from contact patch
Through-‐Hub Flow Passages
Monday, July 23, 12
Section view looking vertically upwards from contact patch
Through-‐Hub Flow Passages
Monday, July 23, 12
Impact of Through-‐Hub Flow
CI CII
A BA
D
Monday, July 23, 12
Impact of Through-‐Hub Flow
CI CII
CIII
A BA
D
A B
Monday, July 23, 12
Impact of Through-‐Hub Flow
CI CII
CIII CIV
A BA
D
AA B
Monday, July 23, 12
12% decrease in drag with op3mal choice of fairing!
Experimental ValidaBon of Through-‐Hub Flow
Monday, July 23, 12
Brake Cooling Efficiency
Dra
g
Baseline Design
Monday, July 23, 12
Brake Cooling Efficiency
Dra
g
Design with Maximum Cooling
Monday, July 23, 12
Brake Cooling Efficiency
Dra
g
Design with Minimum Drag
Monday, July 23, 12
Brake Cooling Efficiency
Dra
g
Optimal Design
Monday, July 23, 12
Design using Computations
Monday, July 23, 12
Quieting A JetJoe Nichols
Monday, July 23, 12
Monday, July 23, 12
Rectangular nozzles
Baseline (NA2Z)
Design taken from the “Extensible Rectangular Nozzle Model System” (Frate & Bridges, 2011)
2:1 aspect ra3o, matching experiment precisely
Chevron (NA2C3)
Monday, July 23, 12
Flow development (Baseline)
Preferen7al spreading along minor axis (Zaman, 1996)Monday, July 23, 12
Flow development (Chevrons)
Monday, July 23, 12
Typical supercomputer usage
One liJle square = 128 processors
Monday, July 23, 12
Full system run (163,840 cores)
Monday, July 23, 12
Flow and noise visualizaBon
Baseline (NA2Z) Chevrons (NA2C3)
FWH
LES
FWH
LES
Monday, July 23, 12
Effect of chevronsUpstream Downstream
Chevrons have two (good) effects on noise:
1.Reduc3on of shock-‐associated noise (upstream)
2.Reduc3on of turbulent mixing noise (downstream)
baselinechevrons
baselinechevrons
Monday, July 23, 12
a new planet in 7 DaysAlan Wray, Javier Jimenez, Parviz Moin, Ali Mani, Lee Shunn, Frank Ham, Gianluca Iaccarino
Monday, July 23, 12
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
Keplerian turbulence
• Protoplanetary disks need to be turbulent to form planets• Simplest model is rotating, sheared box of
turbulence
Ωx1
x2
x3
Monday, July 23, 12
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
Range of scales
Monday, July 23, 12
Energy spectrum
Low-Ro (fast rotation)
not all eddies are dying!
Monday, July 23, 12
Conclusions
• 7 days on BGL and still no planet• Now we know what to look for and where
Monday, July 23, 12
Conclusions
• 7 days on BGL and still no planet• Now we know what to look for and where
Monday, July 23, 12
Thank You Turbulence & ComputingBeauty and the Beast
center for turbulence researchParviz Moin
Gianluca IaccarinoJoe. W. Nichols
John Axerio-Cilies Frank Ham
Heinz PitschMarcus Herrmann
Monday, July 23, 12