ERCOFTAC/SIG 42

7th Workshop on Synthetic Turbulence Models

 22^nd-23^rd September 2011, London, United Kingdom

 How to assemble and disassemble turbulence

and

how do things assemble and disassemble in it?

Imperial College, London, Department of Aeronautics

· Co-organizer (local): Prof J.C. Vassilicos
Dept. of Aeronautics, Imperial College London
South Kensington Campus, 
London, SW7 2PG, United Kingdom
· Co-organizer (local): Dr S. Laizet
S.Laizet@Imperial.ac.uk
Dept. of Aeronautics, Imperial College London
South Kensington Campus, 
London, SW7 2PG, United Kingdom
· Co-organizer: Dr F. Nicolleau
F.Nicolleau@sheffield.ac.uk
University of Sheffield, Sheffield Fluid Mechanics, SFMG - Department of Mechanical Engineering
Mappin Street
Sheffield S1 3JD, United Kingdom
· Co-organizer: Dr A. Nowakowski
A.F.Nowakowski@sheffield.ac.uk
University of Sheffield, Sheffield Fluid Mechanics, SFMG - Department of Mechanical 
EngineeringMappin Street
Sheffield S1 3JD, United Kingdom

Aims of the workshop:

- This workshop is the 7th  workshop held by the ERCFOFTAC

  Special Interest Group on Synthetic Turbulence Models. It follows those held 

·         29th-30th May 2007,               The University of Sheffield, UK                 ERCOFTAC bulletin 75, 2007

·         29th-30th November 2007       UPC, Vilanova i la Geltru, Spain               ERCOFTAC bulletin 77, 2008

·         3th-4th July 2008                     The University of Newcastle, UK              ERCOFTAC bulletin 79, 2009

·         11th-12th December 2008       Nancy-Université; France                          ERCOFTAC bulletin 79, 2009

·         1st-3rd July 2009                    Warsaw University of Technology, Poland  ERCOFTAC bulletin 81, 2009

·         15th-6th July 2010                  Ecole Centrale de Lyon, France                  ERCOFTAC bulletin ??, 2011

Workshop Program:

Preliminary talks & programme: (length of talks: 25 min + 5 min for questions)

A. Baggaley, University of Newcastle upon Tyne, UK

Vortex density fluctuations in quantum turbulence

C. Cambon, Laboratoire de Mécanique des Fluides et d'Acoustique École Centrale de Lyon, France

Interest and limitations of the 4/5 Kolmogorov's law, from isotropic to strongly anisotropic turbulence

B. Devenish, Met Office, UK

Lagrangian stochastic models of multi-particle dispersion

I. Eames, University College, London, UK

Application of KS to determining forces, wakes and dynamics of rigid particles and droplets

M. Farhan, F. Nicolleau and A. F. Nowakowski, Sheffield Fluid Mechanics Group, University of Sheffield, UK

Clustering in Kinematic Simulation flows

J.M. Garcia De La Cruz Lopez, Imperial College London, UK

Experimental study of free surface mixing and chaotic flows

A. Jaouabi, Laboratoire de Mécanique des Fluides, Département de Physique, Faculté des Sciences de Tunis, Tunisia

Numerical study of turbulent diffusion in homogeneous stably stratified turbulence using linear analysis

M. Jensen, Niels Bohr Institute, Copenhagen, Denmark

Shell model approaches to turbulence

C. Keylock, SFMG, Department of Civil and Structural Engineering, University of Sheffield, UK

Synthetic turbulence by gradual wavelet reconstruction

T. Michelitsch, Université Pierre et Marie Curie, Institut Jean le Rond d'Alembert, Paris, France

The self-similar field and its application to stochastic motions

F. Nicolleau, Sheffield Fluid Mechanics Group, University of Sheffield, UK

Richardson's assumption and non-Kolmogorov turbulence

Elena Meneguz and M. Reeks, School of Mechanical & Systems Engineering, University of Newcastle, UK

Statistical properties of particle segregation in homogeneous isotropic turbulence

R. Onishi, Earth Simulater Center (ESC), Japan

TBA

J.M. Redondo, Fisica Aplicada UPC, Spain

Diffusion in non-homogeneous flows. Lagrangian and Eulerian measurements

M. Reeks, School of Mechanical & Systems Engineering, University of Newcastle, UK

Modelling particle transport in tutbulent flows and the use of synthetic models of turbulence

Audience:
This workshop will be the seventh on synthetic turbulence organised by ERCOFTAC/SIG 42. It is open to anyone interested in flow modelling and/or "synthetic turbulence" including (but not restricted to)  Kinematic Simulation, (KS hereinafter). 

More fundamental talks on particle dispersion in turbulent flows are also welcome.

The workshop will also welcome people from the COST action on "Particles in Turbulence" following last meeting in Rome 18-19 December 2009.

Motivation:
KS is widely used in various domains, including Lagrangian aspects in turbulence mixing/stirring, particle dispersion/clustering, and last but not least, aeroacoustics. Flow realisations with complete spatial, and sometime spatio-temporal, dependency, are generated via superposition of random modes (mostly spatial, and sometime spatial and temporal, Fourier modes), with prescribed constraints such as: strict incompressibility (divergence-free velocity field at each point), high Reynolds energy spectrum, ... Recent improvements consisted in incorporating linear dynamics, for instance in rotating and/or stably-stratified flows, with possible easy generalisation to MHD flows, and perhaps to plasmas. KS for channel flows have also been validated.

However, the absence of "sweeping effects" in present conventional KS versions is identified as a major drawback in very different applications: inertial particle clustering as well as in aeroacoustics. Nevertheless, this issue was addressed in some reference papers, and merits to be revisited in the light of new studies in progress. The present workshop will investigate the use of  KS and other synthetic turbulence models for the particular application to environmental flows.

A non-exhaustive list of related topics can be proposed as follows:

- improvement of the modelling of small scales advection by largest scales (sweeping),
- introduction of strongly anisotropic energy spectra with better randomization of the wave-vector,
- analogy with initialisation of DNS/LES and with "Particle Representation Models",
- use of specific modes consistent with geometric constraints, e.g. solid walls, instead of 3D spatial Fourier modes,
- improvement of KS as a subgrid model for LES : Lagrangian diffusion and aeroacoustics,
- competition between "wavy" (really spatio-temporal, propagating) and "vortical" structures of the velocity field for organizing  Lagrangian turbulence diffusion, from fluid to plasma turbulence,
- other "synthetic" models, e.g. to afford intermittency, possibly very different from conventional KS.

Participants (preliminary):

The conference will be held at

Imperial College, London, United Kingdom