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Outline - Clarkson University 4Double Diffusive Convection 4Thermal Convection 4Isotropic Turbulence...

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1 G. Ahmadi ME 639-Turbulence G. Ahmadi ME 639-Turbulence Outline Outline 4 4 Double Diffusive Convection Double Diffusive Convection 4 4 Thermal Convection Thermal Convection 4 4 Isotropic Turbulence Isotropic Turbulence 4 4 Bifurcation Bifurcation 4 4 Turbulence Turbulence G. Ahmadi ME 639-Turbulence S. A. Abu S. A. Abu - - Zaid Zaid and G. Ahmadi, and G. Ahmadi, Appl Appl . Math. Modeling, Vol. 13 (1989) . Math. Modeling, Vol. 13 (1989) 1 T 2 T 1 S 2 S Fluid Layer heat from below with a Fluid Layer heat from below with a salt concentration gradient salt concentration gradient G. Ahmadi ME 639-Turbulence ( ) ( ) ( ) u u u u 2 0 0 t 0 g p p ρν + ρ ρ + −∇ = + ρ T T T 2 T t κ = + u S S S 2 S t κ = + u 0 = u Governing Equations Governing Equations ( ) ( ) ( ) 0 0 0 S S T T 1 β + α ρ = ρ
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1

G. AhmadiME 639-Turbulence G. AhmadiME 639-Turbulence

OutlineOutline44Double Diffusive ConvectionDouble Diffusive Convection44Thermal ConvectionThermal Convection44Isotropic TurbulenceIsotropic Turbulence44BifurcationBifurcation44TurbulenceTurbulence

G. AhmadiME 639-Turbulence

S. A. AbuS. A. Abu--ZaidZaid and G. Ahmadi, and G. Ahmadi, ApplAppl. Math. Modeling, Vol. 13 (1989). Math. Modeling, Vol. 13 (1989)

1T

2T

1S

2S

Fluid Layer heat from below with a Fluid Layer heat from below with a salt concentration gradientsalt concentration gradient

G. AhmadiME 639-Turbulence

( ) ( ) ( ) uuuu 200t0 gpp ∇ρν+ρ−ρ+−−∇=∇⋅+∂ρ

TTT 2Tt ∇κ=∇⋅+∂ u

SSS 2St ∇κ=∇⋅+∂ u

0=⋅∇u

Governing EquationsGoverning Equations

( ) ( )( )000 SSTT1 −β+−α−ρ=ρ

2

G. AhmadiME 639-Turbulence

Stream FunctionStream Function ( )ψ∂ψ∂−= xz ,0,u

NondimensionalNondimensional Governing EquationsGoverning Equations

( )( )( )( )t,z,xz1SSS

t,z,xz1TTT

0

0

Σ+−∆=−θ+−∆=−

( )[ ] ψ∇+Σ∂−θ∂=ψ∇ψ+ψ∇∂σ− 4xSxT

22t

1 RR,J

( ) θ∇+ψ∂=θψ+θ∂ 2xt ,J

( ) Σ∇τ+ψ∂=Σψ+Σ∂ 2xt ,J

G. AhmadiME 639-Turbulence

( ) θ∂ψ∂−θ∂ψ∂=θψ xyyx,J

νκ∆α

=T

3

TTdgR

νκ∆β

=S

3

STdgR

Tκν

=σT

skκκ

=

JacobianJacobianThermal Thermal RayleighRayleigh NumberNumber SolutalSolutal RayleighRayleigh NumberNumber

PrandtlPrandtl NumberNumber Lewis NumberLewis Number

G. AhmadiME 639-Turbulence

( ) ( )*21

tXzsinxsinp22 πλπ

πλ

( ) ( )**21

tZz2sin1tYz2sinxcosp22 π

π−π

λπ

⎟⎟⎠

⎞⎜⎜⎝

⎛=θ

( ) ( )**21

tVz2sin1tUzsinxcosp22 π

π−π

λπ

⎟⎟⎠

⎞⎜⎜⎝

⎛=Σ

G. AhmadiME 639-Turbulence

( )UrYrXX ST −+−σ=&

( )Z1XYY −+−=&

( )XYZaZ +−=&

( )V1XkUU −+−=&

( )XUkVaV +−=&

p4a

2π=

T32

2

T Rp

rλπ

=

S32

2

S Rp

rλπ

=

3

G. AhmadiME 639-Turbulence

No NoiseNo Noise With NoiseWith Noise

rrTT = 10= 10

G. AhmadiME 639-Turbulence

With Noise

rrTT = 40= 40

G. AhmadiME 639-Turbulence

With Noise

rrTT = 40= 40

G. AhmadiME 639-Turbulence

With NoiseWith Noise

rrTT = 40= 40

4

G. AhmadiME 639-Turbulence

Different Different rrTT

G. AhmadiME 639-Turbulence

rrTT = 80= 80

G. AhmadiME 639-Turbulence

With NoiseWith NoiseWithout NoiseWithout Noise

rrTT = 40= 40

G. AhmadiME 639-Turbulence

(McLaughlin and (McLaughlin and OrszagOrszag, JFM, 1982), JFM, 1982)

( )θ+∇+π∇−×=∂∂ kvωvv 2Pr

t

θ∇+=θ∇⋅+∂θ∂ 2wRat

v

0=⋅∇ v

Governing EquationsGoverning Equations

5

G. AhmadiME 639-Turbulence

vω ×∇=

2v21p +=π

νκ∆β

=THgRa

3

κν

=Pr

RayleighRayleighNumberNumber

PrandtlPrandtlNumberNumber

VorticityVorticity

Pressure Pressure HeadHead

G. AhmadiME 639-Turbulence

( ) ( ) ( )∑ ∑ ∑< < =

⎟⎠⎞

⎜⎝⎛ +π

=M

21m N

21n

P

0pP

Yny

Xmxi2

z2Tet,p,n,m~t,z,y,x vv

( ) ( ) ( )∑ ∑ ∑< < =

⎟⎠⎞

⎜⎝⎛ +π

θ=θM

21m N

21n

P

0pP

Yny

Xmxi2

z2Tet,p,n,m~t,z,y,x

FourierFourier--ChebyshevChebyshev SeriesSeries

G. AhmadiME 639-Turbulence

Ra=15000 Ra=25000

G. AhmadiME 639-Turbulence

(G. Ahmadi and V.W. Goldschmidt, (G. Ahmadi and V.W. Goldschmidt, Developments in Mechanics Vol. 6, 1971)Developments in Mechanics Vol. 6, 1971)

NavierNavier--StokesStokes

f2

Lfff

f

Re1P1

tuuuu

∇+∇ρ

−=∇⋅+∂∂

0f =⋅∇ u

6

G. AhmadiME 639-Turbulence

( ) ( )∑ ⋅=K

xKuxu if et,Kt,Fourier SeriesFourier Series

( ) ( )

( ) ( )

( ) ( )

( ) ( ) ⎪⎪⎪⎪

⎪⎪⎪⎪

⎪⎪⎪⎪

⎪⎪⎪⎪

−−⎥⎥⎦

⎢⎢⎣

+−

+

−−⎥⎥⎦

⎢⎢⎣

+−+

−−⎥⎥⎦

⎢⎢⎣

+−

+−=κκ

∂∂

∑∑

∑∑

∑∑

1̀x

1y

1̀x

1y

1̀x

1y

K K

1yy

1xx

1y

1x2

y2x

yxy

K K

1yy

1xx

1y

1x2

y2x

2x

y

K K

1yy

1xx

1y

1x2

y2x

2x

x

yxL

2y

2x

yx

t,KK,KKvt,K,KvKKKK

K

t,KK,KKvt,K,KuKK

K21K

t,KK,KKut,K,KuKK

K1K

i

t,K,KuRe

KKt,,

tu

xx--ComponentComponent

G. AhmadiME 639-Turbulence

( ) ( )

( ) ( )

( ) ( )

( ) ( )⎪⎪⎪⎪

⎪⎪⎪⎪

⎪⎪⎪⎪

⎪⎪⎪⎪

−−⎥⎥⎦

⎢⎢⎣

+−+

−−⎥⎥⎦

⎢⎢⎣

+−+

−−⎥⎥⎦

⎢⎢⎣

+−

⎥⎥⎦

⎢⎢⎣

⎡ +−=

∂∂

∑∑

∑∑

∑∑

1x

1y

1x

1y

1x

1y

K K

1yy

1xx

1y

1x2

y2x

2y

y

K K

1yy

1xx

1y

1x2

y2x

2y

x

K K

1yy

1xx

1y

1x2

y2x

yxx

yxL

2y

2x

yx

t,KK,KKvt,K,KvKK

K1K

t,KK,KKvt,K,KuKK

K21K

t,KK,KKut,K,KuKK

KKK

i

t,K,KvRe

KKt,K,Kv

t

( ) ( ) 0Kt,K,KvKt,K,Ku yyxxyx =⋅+⋅

yy--ComponentComponent

ContinuityContinuity

G. AhmadiME 639-Turbulence

Isotropic Isotropic TurbulenceTurbulence

G. AhmadiME 639-Turbulence

Isotropic TurbulenceIsotropic Turbulence

Longitudinal Longitudinal Lateral Lateral

7

G. AhmadiME 639-Turbulence

Instantaneous Instantaneous Velocity Velocity ContoursContours

G. AhmadiME 639-Turbulence

( )Re,Nt

uu=

∂∂NavierNavier--StokesStokes

Equilibrium Equilibrium SolutionsSolutions

Time InvariantTime Invariant

TimeTime--PeriodicPeriodic

QuasiQuasi--PeriodicPeriodic

ChaoticChaotic

G. AhmadiME 639-Turbulence

BifurcationBifurcation(Supercritical)(Supercritical)

RecrRe

u Stable

Unstable

Bifurcating Bifurcating SolutionsSolutions

G. AhmadiME 639-Turbulence

HopfHopfBifurcationBifurcation

Time Time InvariantInvariant

Time Time PeriodicPeriodic

Regular Regular BifurcationBifurcation

Time Time InvariantInvariant

Time Time InvariantInvariant

Chaotic Chaotic BifurcationBifurcation

QuasiQuasi--PeriodicPeriodic

ChaoticChaotic

8

G. AhmadiME 639-Turbulence

LandauLandau--HopfHopf

CountablyCountably Infinite Bifurcation Infinite Bifurcation of of NavierNavier--Stokes EquationStokes Equation

TurbulenceTurbulence

After Four Bifurcation After Four Bifurcation Solutions to Solutions to NavierNavier--Stokes Stokes Equation Become ChaoticEquation Become Chaotic

RuelleRuelle--TakensTakens

G. AhmadiME 639-Turbulence

G.I. Taylor & von G.I. Taylor & von KarmanKarman (1937)(1937)

““Turbulence is an irregular motion Turbulence is an irregular motion which in general makes its appearance which in general makes its appearance in fluids, gaseous or liquid, when they in fluids, gaseous or liquid, when they flow past solid surfaces or even when flow past solid surfaces or even when neighboring streams of the same fluid neighboring streams of the same fluid flow past or over one another.”flow past or over one another.”

G. AhmadiME 639-Turbulence

HinzeHinze (1959)(1959)

““Turbulent fluid motion is an irregular Turbulent fluid motion is an irregular condition of flow in which the various condition of flow in which the various quantities show a random variation quantities show a random variation with time and space coordinates, so with time and space coordinates, so that statistically distinct average values that statistically distinct average values can be discerned.”can be discerned.”

G. AhmadiME 639-Turbulence

Concluding RemarksConcluding Remarks44Double Diffusive ConvectionDouble Diffusive Convection44Thermal ConvectionThermal Convection44Isotropic TurbulenceIsotropic Turbulence44BifurcationBifurcation44TurbulenceTurbulence


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