Imperial College London

DrSylvainLaizet

Faculty of EngineeringDepartment of Aeronautics

Senior Lecturer
 
 
 
//

Contact

 

+44 (0)20 7594 5045s.laizet Website

 
 
//

Location

 

339City and Guilds BuildingSouth Kensington Campus

//

Summary

 

Publications

Citation

BibTex format

@inproceedings{2013,
title = {Coexistence of regions of equilibrium and non-equilibrium two-point turbulence dynamics in grid-generated turbulence both with -5/3 spectra but different underlying physics},
year = {2013}
}

RIS format (EndNote, RefMan)

TY  - CPAPER
AB - In this paper we present results concerning the spatial development of energy spectra E11( f ) and their associated integral and Taylor scales in conjunction with the spatial developments of vorticity, strain and production rates of vorticity and strain obtained from Direct Numerical Simulations of spatially developing grid-generated turbulence. We use a fractal square grid and a single mesh grid where the mesh is similar to the largest square on the fractal square grid. We find two adjacent but physically different regions in these flows relatively close to the grid: one where the Q-R diagram has not yet formed its well-known, presumed universal, tear-drop shape (Tsinober (2009)) but E11( f ) ∼ f-5/3 over more than a decade of a frequency range which is set by inlet conditions rather than Kolmogorov scalings: and one where the Q-R diagram immediately adopts the well-known tear-drop shape and E11( f ) ∼ f-5/3 over a Kolmogorov range of frequencies which increases as the local Reynolds number increases. In the one case with the higher local Reynolds numbers, the first region gives rise, as one moves downstream, to the non-equilibrium behaviour C ∼ 1/Reλ whilst the second region leads to C =Const.
PY - 2013///
TI - Coexistence of regions of equilibrium and non-equilibrium two-point turbulence dynamics in grid-generated turbulence both with -5/3 spectra but different underlying physics
ER -