scholarly journals Enhanced Dissipation, Hypoellipticity, and Anomalous Small Noise Inviscid Limits in Shear Flows

2017 ◽  
Vol 224 (3) ◽  
pp. 1161-1204 ◽  
Author(s):  
Jacob Bedrossian ◽  
Michele Coti Zelati
Keyword(s):  
Shear Flows ◽  
Small Noise

Fast scalar decay in a shear flow: modes and pseudomodes

2007 ◽  
Vol 572 ◽  
pp. 219-229 ◽  
Author(s):  
J. VANNESTE ◽  
J. G. BYATT-SMITH
Keyword(s):  
Shear Flow ◽  
Eigenvalue Problem ◽  
Decay Rate ◽  
Shear Flows ◽  
Passive Scalar ◽  
Decay Rates ◽  
Constant Speed ◽  
Fast Decay ◽  
Small Noise ◽  
Stream Direction

The decay of a passive scalar in a sinusoidal shear flow translating in the cross-stream direction at a constant speed u is studied in the limit of small diffusivity κ. The decay rate, obtained by solving an eigenvalue problem, is found to tend to a non-zero constant as κ→0 when u is of order κ1/2. This result, establishing that fast decay is possible in shear flows, is fragile however: because of the existence of pseudomodes, the addition of a small noise leads to decay rates that decrease to zero with κ as κ2/5.

Monotonically integrated large eddy simulation of free shear flows

AIAA Journal ◽  
1999 ◽  
Vol 37 ◽  
pp. 544-556 ◽  
Author(s):  
C. Fureby ◽  
F. Grinstein
Keyword(s):  
Large Eddy Simulation ◽  
Shear Flows ◽  
Eddy Simulation ◽  
Large Eddy
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