scholarly journals ANALYSIS OF CLOUD DROPLET SIZE SPECTRA BY JENSEN-SHANNON DIVERGENCE

Anales AFA ◽  
2019 ◽  
Vol 30 (3) ◽  
pp. 52-57
Author(s):  
G. Aguirre Varela ◽  
M. Re ◽  
D. Stoler Flores
Keyword(s):  
Kernel Method ◽  
Cloud Droplet ◽  
Energy Dissipation Rate ◽  
Turbulence Energy ◽  
Laboratory Measurements ◽  
Experimental Conditions ◽  
Size Spectra ◽  
Turbulence Energy Dissipation ◽  
Droplet Sizes ◽  
Jensen Shannon Divergence

The purpose of this work is to use the divergence of Jensen-Shannon to compare spectra of cloud droplet sizes corresponding to different experimental conditions. Results of laboratory measurements are analyzed in which the diameter of droplets, produced by means of an ultrasonic nebulizer, are determined, subject to different movement conditions within a "cloudbox". The turbulence energy dissipation rate is particularly considered. The droplet spectra were approximated by the density kernel method.

Sensitizing the Dissipation Equation to Irrotational Strains

1980 ◽  
Vol 102 (1) ◽  
pp. 34-40 ◽  
Author(s):  
K. Hanjalic´ ◽  
B. E. Launder
Keyword(s):  
Energy Transfer ◽  
Energy Dissipation ◽  
Boundary Layers ◽  
Dissipation Rate ◽  
Energy Dissipation Rate ◽  
Turbulent Boundary Layers ◽  
Turbulence Energy ◽  
Turbulence Energy Dissipation ◽  
Dissipation Equation

The paper recommends the addition of an extra term to the conventional approximate transport equation for the turbulence energy dissipation rate. The term may be interpreted as emphasizing the role of irrotational deformations in promoting energy transfer across the spectrum or, equivalently, of augmenting the influence of normal strains. Calculations, including the new term, are reported for the plane and round jet, and for several turbulent boundary layers. In the cases considered the addition of the new term significantly improves agreement with experiment.

Progress in the development of a Reynolds-stress turbulence closure

1975 ◽  
Vol 68 (3) ◽  
pp. 537-566 ◽  
Author(s):  
B. E. Launder ◽  
G. J. Reece ◽  
W. Rodi
Keyword(s):  
Shear Flows ◽  
Numerical Solutions ◽  
Mixing Layer ◽  
Plane Channel ◽  
Energy Dissipation Rate ◽  
Turbulence Energy ◽  
Reynolds Stresses ◽  
Turbulence Energy Dissipation ◽  
Model Equations ◽  
Plane Channel Flow

The paper develops proposals for a model of turbulence in which the Reynolds stresses are determined from the solution of transport equations for these variables and for the turbulence energy dissipation rate ε. Particular attention is given to the approximation of the pressure-strain correlations; the forms adopted appear to give reasonably satisfactory partitioning of the stresses both near walls and in free shear flows.Numerical solutions of the model equations are presented for a selection of strained homogeneous shear flows and for two-dimensional inhomogeneous shear flows including the jet, the wake, the mixing layer and plane channel flow. In addition, it is shown that the closure does predict a very strong influence of secondary strain terms for flow over curved surfaces.

scholarly journals Measurement of Atmospheric Turbulence by 2-μm Doppler Lidar

2005 ◽  
Vol 22 (11) ◽  
pp. 1733-1747 ◽  
Author(s):  
Igor Smalikho ◽  
Friedrich Köpp ◽  
Stephan Rahm
Keyword(s):  
Velocity Structure ◽  
Energy Dissipation Rate ◽  
Doppler Spectrum ◽  
Turbulence Energy ◽  
Doppler Lidar ◽  
Coherent Doppler Lidar ◽  
Turbulence Energy Dissipation ◽  
Spectrum Width ◽  
Velocity Structure Function ◽  
Theoretical Results

Abstract Two methods for the estimation of the turbulence energy dissipation rate (TEDR) from data measured by a 2-μm coherent Doppler lidar are described in this paper. Based on data measured at the Tarbes-Lourdes-Pyrénées International Airport in summer 2003, height profiles of TEDR have been retrieved. The results of TEDR estimation both from the Doppler spectrum width and from the velocity structure function are compared. Moreover, the experiment has been treated by numerical simulation and the theoretical results have been used for verification of the described methods.

Sign in / Sign up

Export Citation Format

Share Document