turbulence and computing: beauty and the beast - assistant professor gianluca iaccarino

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