A Comparison of Length Scales and Decay Times of Turbulence in Stably Stratified Flows

1986 ◽  
Vol 16 (11) ◽  
pp. 1847-1854 ◽  
Author(s):  
William R. Crawford
Keyword(s):  
Stratified Flows ◽  
Length Scales ◽  
Stably Stratified Flows ◽  
Decay Times

scholarly journals Turbulent Prandtl number and characteristic length scales in stably stratified flows: steady-state analytical solutions

2021 ◽  
Author(s):  
Sukanta Basu ◽  
Albert A. M. Holtslag
Keyword(s):  
Prandtl Number ◽  
Characteristic Length ◽  
Stratified Flows ◽  
Turbulent Prandtl Number ◽  
Length Scales ◽  
Functional Relationships ◽  
Stably Stratified Flows ◽  
Theoretical Predictions ◽  
The Stability ◽  
Theoretical Foundations

AbstractIn this study, the stability dependence of turbulent Prandtl number ($$Pr_t$$ P r t ) is quantified via a novel and simple analytical approach. Based on the variance and flux budget equations, a hybrid length scale formulation is first proposed and its functional relationships to well-known length scales are established. Next, the ratios of these length scales are utilized to derive an explicit relationship between $$Pr_t$$ P r t and gradient Richardson number. In addition, theoretical predictions are made for several key turbulence variables (e.g., dissipation rates, normalized fluxes). The results from our proposed approach are compared against other competing formulations as well as published datasets. Overall, the agreement between the different approaches is rather good despite their different theoretical foundations and assumptions.

scholarly journals Stably Stratified Flows: A Model with No Ri(cr)*

2008 ◽  
Vol 65 (7) ◽  
pp. 2437-2447 ◽  
Author(s):  
V. M. Canuto ◽  
Y. Cheng ◽  
A. M. Howard ◽  
I. N. Esau
Keyword(s):  
Numerical Simulation ◽  
Large Eddy Simulation ◽  
Direct Numerical Simulation ◽  
Turbulent Mixing ◽  
Stratified Flows ◽  
The Other ◽  
Large Set ◽  
Eddy Simulation ◽  
Stably Stratified Flows ◽  
Large Eddy

Abstract A large set of laboratory, direct numerical simulation (DNS), and large eddy simulation (LES) data indicates that in stably stratified flows turbulent mixing exists up to Ri ∼ O(100), meaning that there is practically no Ri(cr). On the other hand, traditional local second-order closure (SOC) models entail a critical Ri(cr) ∼ O(1) above which turbulence ceases to exist and are therefore unable to explain the above data. The authors suggest how to modify the recent SOC model of Cheng et al. to reproduce the above data for arbitrary Ri.

scholarly journals Stratified Turbulence: A Possible Interpretation of Some Geophysical Turbulence Measurements

2008 ◽  
Vol 65 (7) ◽  
pp. 2416-2424 ◽  
Author(s):  
James J. Riley ◽  
Erik Lindborg
Keyword(s):  
Inertial Range ◽  
Geophysical Flows ◽  
Stratified Flows ◽  
Stratified Turbulence ◽  
Length Scales ◽  
Turbulence Measurements ◽  
Atmospheric Data ◽  
Geophysical Turbulence ◽  
Similar Dynamic

Abstract Several existing sets of smaller-scale ocean and atmospheric data appear to display Kolmogorov–Obukov–Corrsin inertial ranges in horizontal spectra for length scales up to at least a few hundred meters. It is argued here that these data are inconsistent with the assumptions for these inertial range theories. Instead, it is hypothesized that the dynamics of stratified turbulence explain these data. If valid, these dynamics may also explain the behavior of strongly stratified flows in similar dynamic ranges of other geophysical flows.

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