[GTP] GTP Seminar March 6, 2012

[Carolyn Mueller]

Tuesday, March 6, 2012
Refreshments
Mesa Laboratory, Main Auditorium
Lecture at 11:00am

Non Kolmogorov Elements in Small-scale Turbulence Dynamics:
bypassing the Cascade
James G. Brasseur
Pennsylvania State University
APS Faculty Fellow, NCAR


The Kolmogorov 1941 (K41) phenomenology dominates our understanding of 
internal interscale dynamics within high Reynolds number free 
turbulence. In particular, K41 underlies a description of inertial 
turbulence dynamics that is restricted, on average, to nonlinear 
interactions among turbulence motions that are commensurate in scale. 
Thus, the small-scale dissipation-dominant turbulence motions 
dynamically communicate with the large-scale energy-dominant motions 
only indirectly, through a sea of local scale interactions that 
progressively isotropize turbulence structure as energy and momentum 
move to progressively smaller scales. Kolmogorov dynamics, however, is 
restricted to turbulence in equilibrium. There exist potentially useful 
unexplored nonlinear interscale dynamics when turbulence is forced out 
of equilibrium. I will address three interrelated dynamics in a general 
discussion of scale interactions in high Reynolds number free 
turbulence, contrasting equilibrium and nonequilibrium turbulence 
dynamics: (1) fundamental issues of energy exchange within triadic 
interactions and general features of “local,” “non-local,” and “distant” 
triadic interactions, (2) nonclassical interscale inertial dynamics as 
fully developed isotropic decaying turbulence is anisotropically forced 
from equilibrium, and (3) a study in which the phase changes at the 
small scales are found to be strongly influenced by distant triadic 
interactions in stationary isotropically forced turbulence.



Carolyn Mueller
NCAR IMAGe
1850 Table Mesa Drive 
Boulder, CO 80305 
www.image.ucar.edu 
Tel: 303 497-2491
Fax: 303-497-2483