Isaac Newton Institute for Mathematical Sciences

Turbulence

January - June 1999

Organisers: GF Hewitt (Imperial College), PA Monkewitz (Lausanne), N Sandham (QMW), JC Vassilicos (Cambridge)

 Research Programme on Turbulence

Symposium on 

TURBULENCE STRUCTURE

Isaac Newton Institute for Mathematical Sciences,

Cambridge, UK

In association with ERCOFTAC 

March 15 - 19, 1999

 Background    Organisation   Programme (updated 10/03/99)  Further Information

Background

Turbulence is characterised by a large number of weakly correlated motions on a wide range of length-and-time-scales and appears disordered but also contains long-lived organised elements. Indeed, recent numerical and experimental observations have revealed the spontaneous formation of little shear layers and vortex tubes which are surrounded by what appears as a random and shapeless sea in the small scales of the turbulence.

First of all, there is a need to establish the importance of these vortical structures. Could they be thought of as 'eigen-structures', what are their stability properties, their geometrical statistics, how do they interact or not interact with each other and with surrounding turbulence, and what are their dissipative properties? Are the near-singularities of the turbulence or the conjectured finite-time singularities related to vortical or other (e.g. straining) sructures, and if so what kind? What are the Eulerian and the Langrangian properties of such structures, and how do their conditional statistics relate to the well-established unconditional Eulerian and Lagrangian statistics (e.g. spectra, energy cascades up-and-down-scale, relative motions of particles) and the scaling properties of the entire flow? To what extent can turbulence be represented in terms of space-filling functions such as Fourier or Chebychev basis functions or is it necessary to work in terms of localised functions such as wavelets?

Can answers to the above questions, in particular those relating to energy transfer and dissipation, be used for novel turbulence modelling? Finally, and most importantly, what are the universal aspects of the statistical, structural and modelling facets of the turbulence problem, and how do they relate to each other?

This symposium will address the mathematical aspects of vortex dynamics including interactions between vortices and turbulence, representations of complex internal structure and connections to statistics and statistical modelling of turbulence. Developments in the study of university of small-scale turbulence will be emphasised.

Organisation

The Symposium is being organised by J.C.R. Hunt and J.C. Vassilicos in collaboration with the other Organisers of the Isaac Newton Institute Research Programme on Turbulence and supported by the Scientific Advisory Committee of the Programme.

The Organisers of the INI Research Programme are as follows:

The Symposium will be held at the Isaac Newton Institute, 20 Clarkson Road, Cambridge CB3 0EH, UK (tel: 01223 335999, fax: 01223 330508.

Provisional Programme

Monday 15 March

08.30-09.15 Registration

09.15-09.30 HK Moffatt (Cambridge)
Welcome by Director

09.30-10.15 EA Novikov (California)
Vortical structure & modelling of turbulence

10.15-11.00 AB Tsinober (Tel-Aviv)
Vortex stretching & production of strain/dissipation

11.00-11.45 Coffee & Posters

11.45-12.30 Z Warhaft (Cornell)
The issue of local isotropy of velocity & scalar turbulent fields

12.30-14.00 Lunch

14.00-14.45 JG Brasseur (Pennsylvania State)
Transition from isotropic to shear-dominated vortex structure in physical & fourier space

14.45-15.30 JC Vassilicos (Cambridge)
Dynamics of near-singular vortex

15.30-15.50 P Chainais (Ecole Normale Superieure)
Intermittency & coherent structures in a swirling flow: a wavelet analysis of joint pressure and velocity measurements

15.50-16.30 Tea & Posters

16.30-16.50 BI Shraiman (Bell Laboratories)
Lagrangian tetrad dynamics & the statistical geometry of turbulence

16.50-17.10 E Gaudin (LPMMH-ESPCI)
Influence of coherent structures on velocity and passive scalar statistics in turbulent regime

16.50-17.40 General Discussion

17.40-19.00 Wine Reception

Tuesday 16 March

09.00-09.45 HK Moffatt (Cambridge)
A singularity of the Navier Stokes equations associated with vortex interactions?

09.45-10.30 JD Gibbon (Imperial)
Vorticity alignment in the three-dimensional Euler & Navier-Stokes equations

10.30-10.50 Y Kimura (Nagoya)
Gradient enhancement & filament ejection for non-uniform elliptic vortex in 2D turbulence

10.50-11.30 Coffee & Posters

11.30-12.15 CF Barenghi (Newcastle)
Vortex lines & vortex tangles in superfluid helium

12.15-12.35 C Baudet (Ecole Normale Superieure)
Experimental detection of coherent vorticity structures using a full spectral technique

12.35-14.00 Lunch

14.00-14.45 RM Kerr (NCAR)
Applications of vortex dynamics to MHD current dynamics

14.45-15.30 Y Fukumoto (Kyushu)
Large motion & expansion of a viscous vortex ring

15.30-15.50 H Hanazaki (Tohoku)
Linear processes in unsteady stably stratified turbulence with mean shear

15.50-16.30 Tea & Posters

16.30-16.50 M Tanahashi (Tokyo Institute of Technology)
Statistics of coherent fine scale eddies in turbulent channel flows

16.50-17.10 P Flohr (Cambridge)
Self-similar spiral streamlines & local flow alignment in DNS turbulence

17.10-18.00 General Discussion

Wednesday 17 March

09.00-09.45 Y Couder (Ecole Normale Superieure)
The interaction between stretching & rotation : from the laminary to the turbulent situations

09.45-10.30 F Hussain (Houston)
Core dynamics instability of a vortex in shear: a physical-space cascade mechanism

10.30-10.50 C Lee (Tsinghua)
Flow structures in transitional & turbulent flat plate boundary layers: measurement & visualization

10.50-11.30 Coffee & Posters

11.30-12.15 C Williamson (Cornell)
Fundamental instabilities in spatially - developing & temporally - developing vortex pairs

12.15-12.35 T Leweke (IRPHE)
Experimental study of elementary vortex interactions: reconnection & merging

12.35-14.00 Lunch

14.00-14.45 C Cambon (LMFU at ECL)
Stability of vortex structures in a rotating frame

14.45-15.30 S Le Dizes (IRPHE)
Structure & stability of a new family of non-axisymmetric vortex solutions

15.30-15.50 A Maurel (LOA - ESPCI)
Dynamical investigation of a vortex using time-reversal mirrors

15.50-16.30 Tea & Posters

16.30-16.50 F Bottausci (LPMMH - ESPCI)
Experimental study of stretched vortices

16.50-17.10 P Petitjeans (LPMMH - ESPCI)
Experimental study of vortices created by a 'double rotating suction' system

17.10-18.00 General Discussion

Thursday 18 March

09.00-09.45 T Perry (Melbourne)
Structure based modelling for turbulent boundary layers

09.45-10.30 JF Morrison (Imperial)
Structure & energy transfer in wall-bounded turbulence

10.30-10.50 R Nagaosa (National Institute for Resorces & Environment)
Dynamics of vortex layers and tubes in free-surface & near-wall turbulent shear flow

10.50-11.30 Coffee & Posters

11.30-12.15 M Lesieur (Institut de Mecanique de Grenoble)
LES & vortex topology in shear & rotating flows

12.15-12.35 K Horiuti (Tokyo Institute of Technology)
Subgrid-scale energy transfer & vortex sheet/tube structures in turbulence

12.35-14.00 Lunch

14.00-14.45 A Leonard (California Institute of Technology)
Evolution of localized packets of vorticity in turbulence

14.45-15.30 J Hunt (Cambridge)
Vortex dynamics of coherent structures

15.30-15.50 E Fedorovich (Karlsruhe)
Turbulence structure variation in a horizontally evolving convective boundary layer capped by a temperature inversion

15.50-16.30 Tea & Posters

16.30-16.50 D Drikakis (UMIST)
Extraction of coherent structures & modelling of coherent stresses in turbulent flows

16.50-17.10 M Stanislas (Ecole Centrale de Lille)
Experimental study of near wall turbulence using particle image velocimetry

17.10-18.00 General Discussion

19.30-   Conference Dinner, Clare College

Friday 19 March

09.00-09.45 WD McComb (Edinburgh)
Conditional mode elimination with asymptotic freedom for isotropic turbulence at large Reynolds numbers

09.45-10.30 K Ohkitani (Kyoto)
Comparison of vorticity & passive vectors in viscous & inviscid flows

10.30-10.50 X He (Warwick)
A probabilistic method for vortex motion in 2d turbulence

10.50-11.30 Coffee & Posters

11.30-11.50 D Samuels (Newcastle)
Topology of evolving vortex filament tangles

11.50-12.10 W Devenport (Virginia)
Characteristic eddy decompositions in real & model turbulent wakes

12.30-14.00 Lunch

14.00- Final Discussion

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