Acceleration structure in turbulence

Risø, ETH, Tel Aviv Uni

Beat Lüthi, Alex Liberzon, Markus Holzner, Arkady Tsinober,

Søren Ott, Jacob Berg, Jakob Mann

Oct 2009EUROMECH Colloquium 512, Torino

Small Scale Turbulence and Related Gradient Statistics Acceleration structure, 2/23

Aim of talk

gain inisght also in spatial structure (not just magnitude)

strong acceleration in high strain and high enstrophy

for low Re curvature mainly in high enstrophy for high Re curvature in high strain and high enstrophy

geometrical alignments of acceleration quantities

velocity-acceleration struct. func. and energy flux

Introduction

acceleration coupled to small scales, i.e. velocity gradients

Introduction

but also coupled to large scales

High magnitude in strain and/or enstrophy?

larger than unity,but decreasing with Re

High Re – low Re is qualitatively the same for acceleration structure

Re= 70Re= 6600

Particle Tracking Velocimetry, 3d-PTV

r(x,y,z,t)

Aij from 3d-PTV

Accuracy?

Accuracy?Nature 2003:

Acceleration magnitude

three distinct regions

Curvature

no correspondence between strong curvature and strong vorticity

strong curvature is highly correlated with low velocityright tail of PDF scales with -5/2

weak separation upon conditioningon high strain and enstrophy

Curvature

adding velocity results inscaling change from -5/2 to -7/2

streamline curvaturescales with -11/2

stronger separation withhigh strain and enstrophy

Curvaturewhy seemingly enstrophy dominated?al ac cancelation in high strain is low Re effect

Geometrical structure

Velocity acceleration structure function

Conclusions

high acceleration magnitude also in high strain regions curvature scales with -7/2 not with -5/2 if Re is very high identify reason why @ low Re curvature correlates with

vorticity, but why this effects vanishes for high Re

alignment with eigenframe stronger for ac, associated with stream lines

alignments are of kinematical nature

From vel-acc struct function we arrive at similar result for energy flux as Leonard, 1974, Borue&Orzag 1998

Acceleration structure in turbulence

Documents

MSBVH: An Efficient Acceleration Data Structure for Ray

Shear Turbulence: Onset and Structure - University of Chicagopeople.cs.uchicago.edu/~lebovitz/Pdffiles/wally1.pdf · Shear Turbulence: Onset and Structure Fabian Wale e notes by Mart

TURBULENCE MODELS FOR FLUID-STRUCTURE INTERACTION …

Relativistic Particle Acceleration in a Developing Turbulence Relativistic Particle Acceleration in a Developing Turbulence Shuichi M ATSUKIYO ESST Kyushu

NEW PERSPECTIVES IN TURBULENCE - American …the local structure of turbulence shows that the Kolmogorov-Obukhov scaling of the second and third structure functions is exact in the

The structure of isotropic turbulence at very high

Turbulence Structure Laboratory experimental tools

THE TURBULENCE STRUCTURE OF THE STABLE ATMOSPHERIC BOUNDARY LAYER …homepages.see.leeds.ac.uk/~lecimb/publications/BLM2003.pdf · 2003. 3. 10. · THE TURBULENCE STRUCTURE OF THE

Density e˙ects on post-shock turbulence structure and dynamics(VGT) show that density variations significantly change the turbulence structure and flow topology. Specifically,

Wind and turbulence structure in the boundary layer around

STOCHASTIC ACCELERATION OF COSMIC RAYS IN ANISOTROPIC PLASMA TURBULENCE

Effects of turbulence structure and urbanization on …Effects of turbulence structure and urbanization on the heavy haze pollution process Yan Ren1, Hongsheng Zhang1, Wei Wei2, Bingui

Self-similarity and internal structure of turbulence induced by

Alfven Wave Turbulence as a Solar Wind Driver and …Introducing Alfven Waves Turbulence • Hinode observations suggest energy input is sufficient to drive the solar wind acceleration

Electron acceleration by Langmuir turbulence

Turbulence structure behind the shock in canonical shockvortical turbulence interaction

Azimuthal structure of turbulence in high Reynolds … structure of turbulence in high Reynolds number pipe ﬂow SEAN C. C. BAILEY1, MARCUS HULTMARK1, ALEXANDER J. SMITS1 AND MICHAEL

Atmospheric Turbulence Characterization and …...Atmospheric Turbulence Characterization and Wavefr ont Sensing by Means of the Moiré De ectometry 3 (Tay et al., 2004), acceleration

NEW PERSPECTIVES IN TURBULENCE - American Mathematical … · the local structure of turbulence shows that the Kolmogorov-Obukhov scaling of the second and third structure functions

On the Structure of Turbulence in the Bottom Boundary ... Publications/Nimmo_smith_turb_… · On the Structure of Turbulence in the Bottom Boundary Layer of the Coastal Ocean