scholarly journals Time delays and energy transport velocities in three dimensional ideal cloaking devices

2008 ◽  
Vol 104 (3) ◽  
pp. 033113 ◽  
Author(s):  
Huanyang Chen ◽  
C. T. Chan
Author(s):  
Hülya Durur

In this study, the Lonngren-wave equation, which is physically semiconductor, is taken into consideration. Traveling wave solutions of this equation are presented with generalized exponential rational function method, which is one of the mathematically powerful analytical methods. These solutions are produced in bright (non-topological) soliton and complex trigonometric-type traveling wave solutions. Three-dimensional (3D), 2D and contour graphics are presented with the help of a ready-made package program with special values given to constants in these solutions. The effect of the change in wave velocity on the traveling wave solution showing energy transport is presented with the help of simulation. It is argued that velocity is one of the important factors in wave diffraction. In the results and discussion section, the advantages and disadvantages of the method are discussed.


2000 ◽  
Vol 176 ◽  
pp. 362-372
Author(s):  
Å. Nordlund ◽  
R. F. Stein

AbstractWe review properties of stellar convection, as derived from detailed 3-D numerical modeling, and assess to what extent 1-D models are able to provide a fair representation of stellar structure in various regions of the HR diagram. We point out a number of problems and discrepancies that are inevitable when using conventional 1-D models. The problems originate mainly in the surface layers, where horizontal fluctuations become particularly large, and where convective energy transport gives way to radiation. We conclude that it is necessary (and possible) to use three-dimensional models of these layers, in order to avoid the uncertainties and inaccuracies associated with 1-D representations.


Coatings ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 248 ◽  
Author(s):  
Anwar Saeed ◽  
Zahir Shah ◽  
Saeed Islam ◽  
Muhammad Jawad ◽  
Asad Ullah ◽  
...  

In this research, the three-dimensional nanofluid thin-film flow of Casson fluid over an inclined steady rotating plane is examined. A thermal radiated nanofluid thin film flow is considered with suction/injection effects. With the help of similarity variables, the partial differential equations (PDEs) are converted into a system of ordinary differential equations (ODEs). The obtained ODEs are solved by the homotopy analysis method (HAM) with the association of MATHEMATICA software. The boundary-layer over an inclined steady rotating plane is plotted and explored in detail for the velocity, temperature, and concentration profiles. Also, the surface rate of heat transfer and shear stress are described in detail. The impact of numerous embedded parameters, such as the Schmidt number, Brownian motion parameter, thermophoretic parameter, and Casson parameter (Sc, Nb, Nt, γ), etc., were examined on the velocity, temperature, and concentration profiles, respectively. The essential terms of the Nusselt number and Sherwood number were also examined numerically and physically for the temperature and concentration profiles. It was observed that the radiation source improves the energy transport to enhance the flow motion. The smaller values of the Prandtl number, Pr, augmented the thermal boundary-layer and decreased the flow field. The increasing values of the rotation parameter decreased the thermal boundary layer thickness. These outputs are examined physically and numerically and are also discussed.


2013 ◽  
Vol 715 ◽  
pp. 335-358 ◽  
Author(s):  
Johan Meyers ◽  
Charles Meneveau

AbstractAs a generalization of the mass–flux based classical stream tube, the concept of momentum and energy transport tubes is discussed as a flow visualization tool. These transport tubes have the property that no fluxes of momentum or energy exist over their respective tube mantles. As an example application using data from large eddy simulation, such tubes are visualized for the mean-flow structure of turbulent flow in large wind farms, in fully developed wind-turbine-array boundary layers. The three-dimensional organization of energy transport tubes changes considerably when turbine spacings are varied, enabling the visualization of the path taken by the kinetic energy flux that is ultimately available at any given turbine within the array.


2020 ◽  
Author(s):  
Fabian Jakub ◽  
Bernhard Mayer

<pre class="moz-quote-pre">Recent studies have shown that the effects of three dimensional radiative transfer may impact cloud formation and precipitation. While one-dimensional solvers are favoured due to their computational simplicity, they do however neglect any horizontal energy transport. In particular, the 1D approximation neglects 3D effects such as cloud side illumination and the displacement of the cloud's shadow at the surface which are relevant whenever the sun is not in the zenith. This has a detrimental effect on the results of high resolution simulations. 3D radiative transfer has the potential to considerably change the boundary layer dynamics, the evolution of clouds, their lifetime and precipitation onset. To this date, studies that investigate the influence of 3D effects on realistic NWP settings are rare, primarily because there haven't been 3D radiative transfer solvers around that were fast enough to be run interactively in a forecast simulation. For that purpose we adapted the TenStream solver (parallel 3D radiative transfer solver for LES) to unstructured meshes and coupled it to ICON-LEM. We will present the new solver in the context of ICON-LEM simulations, the methodologies used and its characteristics.</pre>


2017 ◽  
Vol 72 (2) ◽  
pp. 135-139 ◽  
Author(s):  
Jose Ordonez-Miranda ◽  
Karl Joulain ◽  
Younes Ezzahri

AbstractWe demonstrate that the energy transport of surface phonon-polaritons can be large enough to be observable in a crystal made up of a three-dimensional assembly of nanorods of silicon carbide. The ultralow phonon thermal conductivity of this nanostructure along with its high surface area-to-volume ratio allows the predominance of the polariton energy over that generated by phonons. The dispersion relation, propagation length, and thermal conductance of polaritons are numerically determined as functions of the radius and temperature of the nanorods. It is shown that the thermal conductance of a crystal with nanorods at 500 K and diameter (length) of 200 nm (20 μm) is 0.55 nW·K−1, which is comparable to the quantum of thermal conductance of polar nanowires.


2006 ◽  
Vol 24 (2) ◽  
pp. 283-290 ◽  
Author(s):  
A.M. KHALENKOV ◽  
N.G. BORISENKO ◽  
V.N. KONDRASHOV ◽  
Yu.A. MERKULIEV ◽  
J. LIMPOUCH ◽  
...  

The experience of target fabrication with low-density and cluster heterogeneity is presented. Cluster plasma research is strongly dependent on target fabrication development and target structure characterization. Ten more target parameters should be measured for experiment interpreting in case of micro-heterogeneous plasma. Foam and foil targets, high-Z doped also, are produced and irradiated on the existing laser facilities. The density of 4.5 mg/cc cellulose triacetate in the form of regular three-dimensional polymer networks are achieved which is as low as plasma critical density for the third harmonic of iodine laser light. The possibilities of varying important target parameters, methods of their monitoring are discussed. Experiments with underdense foam targets with or without clusters irradiated on Prague Asterix Laser System (PALS) laser facility are analyzed preliminary for target optimization. Under-critical foams of varying structure (closed-cell foam or three-dimensional networks) and densities are reported for plasma experiments. Thermal and radiation transport in such targets are considered.


2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Wei Shi ◽  
Xiaona Cui ◽  
Xuezhi Li ◽  
Xin-Guang Yang

<p style='text-indent:20px;'>This paper is concerned with the tempered pullback attractors for 3D incompressible Navier-Stokes model with a double time-delays and a damping term. The delays are in the convective term and external force, which originate from the control in engineer and application. Based on the existence of weak and strong solutions for three dimensional hydrodynamical model with subcritical nonlinearity, we proved the existence of minimal family for pullback attractors with respect to tempered universes for the non-autonomous dynamical systems.</p>


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