scholarly journals Characterization of velocity-gradient dynamics in incompressible turbulence using local streamline geometry

2020 ◽  
Vol 895 ◽  
Author(s):  
Rishita Das ◽  
Sharath S. Girimaji
Keyword(s):  
Velocity Gradient ◽  
Gradient Dynamics ◽  
Image Position ◽  
Incompressible Turbulence

scholarly journals Singular perturbations of the unicritical polynomials with two parameters

2016 ◽  
Vol 37 (6) ◽  
pp. 1997-2016 ◽  
Author(s):  
YINGQING XIAO ◽  
FEI YANG
Keyword(s):  
Julia Set ◽  
Dynamical Behavior ◽  
Rational Maps ◽  
Topological Properties ◽  
Fatou Set ◽  
The Family ◽  
Image Position ◽  
Two Parameters ◽  
Unicritical Polynomials

In this paper, we study the dynamics of the family of rational maps with two parameters $$\begin{eqnarray}f_{a,b}(z)=z^{n}+\frac{a^{2}}{z^{n}-b}+\frac{a^{2}}{b},\end{eqnarray}$$ where $n\geq 2$ and $a,b\in \mathbb{C}^{\ast }$. We give a characterization of the topological properties of the Julia set and the Fatou set of $f_{a,b}$ according to the dynamical behavior of the orbits of the free critical points.

Synthesis and characterization of Ni incorporated titanium dioxide thin films

2018 ◽  
Vol 33 (24) ◽  
pp. 4165-4172 ◽  
Author(s):  
Deepak Kumar ◽  
Prasanta Mandal ◽  
Anil Singh ◽  
Charu Pant ◽  
Sudesh Sharma
Keyword(s):  
Thin Films ◽  
Titanium Dioxide ◽  
Synthesis And Characterization ◽  
Titanium Dioxide Thin Films ◽  
Image Position

Abstract

Deposition and characterization of nanostructured Cu2O thin-film for potential photovoltaic applications

2013 ◽  
Vol 28 (13) ◽  
pp. 1740-1746 ◽  
Author(s):  
Nishant Gupta ◽  
Rajendra Singh ◽  
Fan Wu ◽  
Jagdish Narayan ◽  
Colin McMillen ◽  
...  
Keyword(s):  
Thin Film ◽  
Photovoltaic Applications ◽  
Cu2o Thin Film ◽  
Image Position

Abstract

scholarly journals Characterization of swift heavy ion irradiation damage in ceria

2015 ◽  
Vol 30 (9) ◽  
pp. 1473-1484 ◽  
Author(s):  
Clarissa A. Yablinsky ◽  
Ram Devanathan ◽  
Janne Pakarinen ◽  
Jian Gan ◽  
Daniel Severin ◽  
...  
Keyword(s):  
Ion Irradiation ◽  
Heavy Ion ◽  
Irradiation Damage ◽  
Swift Heavy Ion Irradiation ◽  
Heavy Ion Irradiation ◽  
Swift Heavy Ion ◽  
Image Position

Abstract

On velocity gradient dynamics and turbulent structure

2015 ◽  
Vol 780 ◽  
pp. 60-98 ◽  
Author(s):  
J. M. Lawson ◽  
J. R. Dawson
Keyword(s):  
Velocity Gradient ◽  
Local Strain ◽  
Turbulent Structure ◽  
Stochastic Estimation ◽  
Spatially Resolved ◽  
Gradient Dynamics ◽  
Layer Structures ◽  
Non Local ◽  
Conditional Averaging

The statistics of the velocity gradient tensor $\unicode[STIX]{x1D63C}=\boldsymbol{{\rm\nabla}}\boldsymbol{u}$, which embody the fine scales of turbulence, are influenced by turbulent ‘structure’. Whilst velocity gradient statistics and dynamics have been well characterised, the connection between structure and dynamics has largely focused on rotation-dominated flow and relied upon data from numerical simulation alone. Using numerical and spatially resolved experimental datasets of homogeneous turbulence, the role of structure is examined for all local (incompressible) flow topologies characterisable by $\unicode[STIX]{x1D63C}$. Structures are studied through the footprints they leave in conditional averages of the $Q=-\text{Tr}(\unicode[STIX]{x1D63C}^{2})/2$ field, pertinent to non-local strain production, obtained using two complementary conditional averaging techniques. The first, stochastic estimation, approximates the $Q$ field conditioned upon $\unicode[STIX]{x1D63C}$ and educes quantitatively similar structure in both datasets, dissimilar to that of random Gaussian velocity fields. Moreover, it strongly resembles a promising model for velocity gradient dynamics recently proposed by Wilczek & Meneveau (J. Fluid Mech., vol. 756, 2014, pp. 191–225), but is derived under a less restrictive premise, with explicitly determined closure coefficients. The second technique examines true conditional averages of the $Q$ field, which is used to validate the stochastic estimation and provide insights towards the model’s refinement. Jointly, these approaches confirm that vortex tubes are the predominant feature of rotation-dominated regions and additionally show that shear layer structures are active in strain-dominated regions. In both cases, kinematic features of these structures explain alignment statistics of the pressure Hessian eigenvectors and why local and non-local strain production act in opposition to each other.

Synthesis and characterization of germanium-centered three-dimensional crystalline porous aromatic framework

2012 ◽  
Vol 27 (10) ◽  
pp. 1417-1420 ◽  
Author(s):  
Ye Yuan ◽  
Jia Liu ◽  
Hao Ren ◽  
Xiaofei Jing ◽  
Wei Wang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Synthesis And Characterization ◽  
Porous Aromatic Framework ◽  
Image Position

Abstract

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