Energy spectra of three-dimensional harmonium under Debye potential obtained using the shifted 1/N expansion approach

2019 ◽  
Vol 59 (8) ◽  
pp. e201900013
Author(s):  
A.S. Sandouqa
Keyword(s):  
Three Dimensional ◽  
Energy Spectra ◽  
Debye Potential

scholarly journals On inertial-range scaling laws

1996 ◽  
Vol 306 ◽  
pp. 167-181 ◽  
Author(s):  
John C. Bowman
Keyword(s):  
Steady State ◽  
High Resolution ◽  
Scaling Laws ◽  
State Energy ◽  
Three Dimensional ◽  
Inertial Range ◽  
Energy Spectra ◽  
Two Dimensional ◽  
Unified Framework ◽  
Asymptotic Nature

Inertial-range scaling laws for two- and three-dimensional turbulence are re-examined within a unified framework. A new correction to Kolmogorov's k−5/3 scaling is derived for the energy inertial range. A related modification is found to Kraichnan's logarithmically corrected two-dimensional enstrophy-range law that removes its unexpected divergence at the injection wavenumber. The significance of these corrections is illustrated with steady-state energy spectra from recent high-resolution closure computations. Implications for conventional numerical simulations are discussed. These results underscore the asymptotic nature of inertial-range scaling laws.

Simulation of Artificial Turbulence by the Vortex Method

2002 ◽  
Author(s):  
Yoshifumi Ogami ◽  
Kazuie Nishiwaki ◽  
Yoshinobu Yoshihara
Keyword(s):  
Turbulent Flows ◽  
Three Dimensional ◽  
Vortex Method ◽  
Energy Spectra ◽  
System Of Nonlinear Equations ◽  
Vortex Methods ◽  
Velocity Fluctuations ◽  
Integral Scales ◽  
Relative Errors ◽  
Les Model

First, a simple and accurate numerical method is presented to produce velocity fluctuations that are determined by the prescribed physical quantities and qualities of turbulence such as longitudinal and lateral spectra, and integral scales. The fluctuations are obtained by solving a system of nonlinear equations that are derived from the equations of energy spectra and of root mean square of the fluctuations. This method requires as many computer memories and computations as one-dimensional case even for the three dimensional calculations. It is shown that there is a strong resemblance of the simulated velocity fluctuations and experimental data. The energy spectra of these velocity fluctuations are quite accurate with less than 0.01% relative errors to the prescribed spectra. Secondly, these solutions are used to examine the capability of the vortex methods to produce turbulent flows with the prescribed parameters. It is found that although the energy spectra by the vortex method scatter to some extent, they are distributed along the prescribed spectra. It can be said that the vortex methods are able to simulate the target turbulence fairly well. Also it is found that the solutions with the LES model increase and deviate from the target spectrum at the higher frequency regions. This may suggest the nonessentiality of the LES model for the vortex method.

scholarly journals Formation of Power-law Electron Energy Spectra in Three-dimensional Low-β Magnetic Reconnection

2019 ◽  
Vol 884 (2) ◽  
pp. 118 ◽  
Author(s):  
Xiaocan Li ◽  
Fan Guo ◽  
Hui Li ◽  
Adam Stanier ◽  
Patrick Kilian
Keyword(s):  
Magnetic Reconnection ◽  
Electron Energy ◽  
Power Law ◽  
Three Dimensional ◽  
Energy Spectra

scholarly journals On bubble clustering and energy spectra in pseudo-turbulence

2010 ◽  
Vol 650 ◽  
pp. 287-306 ◽  
Author(s):  
JULIÁN MARTÍNEZ MERCADO ◽  
DANIEL CHEHATA GÓMEZ ◽  
DENNIS VAN GILS ◽  
CHAO SUN ◽  
DETLEF LOHSE
Keyword(s):  
Isotropic Turbulence ◽  
Liquid Velocity ◽  
Pair Correlation ◽  
Bubble Diameter ◽  
Three Dimensional ◽  
Radial Distance ◽  
Energy Spectra ◽  
Bubble Velocity ◽  
Vertical Orientation ◽  
Gaussian Form

Three-dimensional particle tracking velocimetry (PTV) and phase-sensitive constant temperature anemometry in pseudo-turbulence – i.e. flow solely driven by rising bubbles – were performed to investigate bubble clustering and to obtain the mean bubble rise velocity, distributions of bubble velocities and energy spectra at dilute gas concentrations (α ≤ 2.2 %). To characterize the clustering the pair correlation function G(r, θ) was calculated. The deformable bubbles with equivalent bubble diameter db = 4–5 mm were found to cluster within a radial distance of a few bubble radii with a preferred vertical orientation. This vertical alignment was present at both small and large scales. For small distances also some horizontal clustering was found. The large number of data points and the non-intrusiveness of PTV allowed well-converged probability density functions (PDFs) of the bubble velocity to be obtained. The PDFs had a non-Gaussian form for all velocity components and intermittency effects could be observed. The energy spectrum of the liquid velocity fluctuations decayed with a power law of −3.2, different from the ≈ −5/3 found for homogeneous isotropic turbulence, but close to the prediction −3 by Lance & Bataille (J. Fluid Mech., vol. 222, 1991, p. 95) for pseudo-turbulence.

scholarly journals Transition to turbulence in an elliptic vortex

1996 ◽  
Vol 307 ◽  
pp. 43-62 ◽  
Author(s):  
T. S. Lundgren ◽  
N. N. Mansour
Keyword(s):  
Swirling Flow ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Periodic Wave ◽  
Transition To Turbulence ◽  
Energy Spectra ◽  
Small Scale ◽  
Two Dimensional ◽  
Secondary Instabilities ◽  
Vortex Tubes

Stability and transition to turbulence are studied in a simple incompressible two-dimensional bounded swirling flow with a rectangular planform – a vortex in a box. This flow is unstable to three-dimensional disturbances. The instability takes the form of counter-rotating swirls perpendicular to the axis which bend the vortex into a periodic wave. As these swirls grow in amplitude the primary vorticity is compressed into thin vortex layers. These develop secondary instabilities which roll up into vortex tubes. In this way the flow attains a turbulent state which is populated by intense elongated vortex tubes and weaker vortex layers which spiral around them. The flow was computed at two Reynolds numbers by spectral methods with up to 2563 resolution. At the higher Reynolds number broad three-dimensional shell-averaged energy spectra are found with nearly a decade of Kolmogorov k−5/3 law and small-scale isotropy.

Variations in energy spectra and water-to-material stopping-power ratios in three-dimensional conformal and intensity-modulated photon fields

2007 ◽  
Vol 34 (4) ◽  
pp. 1388-1397 ◽  
Author(s):  
Si Young Jang ◽  
H. Helen Liu ◽  
Radhe Mohan ◽  
Jeffrey V. Siebers
Keyword(s):  
Three Dimensional ◽  
Energy Spectra ◽  
Stopping Power ◽  
Intensity Modulated

scholarly journals Retrieval of energy spectra for all flavours of neutrinos from core-collapse supernova with multiple detectors

2020 ◽  
Vol 500 (1) ◽  
pp. 319-332
Author(s):  
Hiroki Nagakura
Keyword(s):  
Energy Spectrum ◽  
Three Dimensional ◽  
Large Error ◽  
Neutrino Energy ◽  
Energy Spectra ◽  
Joint Analysis ◽  
Core Collapse ◽  
Neutrino Experiment ◽  
Core Collapse Supernova ◽  
Reaction Channels

ABSTRACT We present a new method by which to retrieve energy spectrum for all falvours of neutrinos from core-collapse supernova (CCSN). In the retrieval process, we do not assume any analytic formulas to express the energy spectrum of neutrinos but rather take a direct way of spectrum reconstruction from the observed data; the singular value decomposition algorithm with a newly developed adaptive energy-gridding technique is adopted. We employ three independent reaction channels having different flavour sensitivity to neutrinos. Two reaction channels, inverse beta decay on proton and elastic scattering on electrons, from a water Cherenkov detector such as Super-Kamiokande (SK) and Hyper-Kamiokande (HK), and a charged current reaction channel with Argon from the Deep Underground Neutrino Experiment (DUNE) are adopted. Given neutrino oscillation models, we iteratively search the neutrino energy spectra at the CCSN source until they provide the consistent event counts in the three reaction channels. We test the capability of our method by demonstrating the spectrum retrieval to a theoretical neutrino data computed by our recent three-dimensional CCSN simulation. Although the energy spectrum with either electron-type or electron-type antineutrinos at the CCSN source has relatively large error compared to that of other species, the joint analysis with HK + DUNE or SK + DUNE will provide precise energy spectrum of all flavours of neutrinos at the source. Finally, we discuss perspectives for improvements of our method by using neutrino data of other detectors.

scholarly journals LOW-LYING STATES IN 30Mg: A BEYOND RELATIVISTIC MEAN-FIELD INVESTIGATION

2011 ◽  
Vol 20 (02) ◽  
pp. 482-487 ◽  
Author(s):  
J.M. YAO ◽  
Z.X. LI ◽  
J. XIANG ◽  
H. MEI ◽  
J. MENG
Keyword(s):  
Mean Field ◽  
Three Dimensional ◽  
Field Investigation ◽  
Low Energy ◽  
Energy Spectra ◽  
Generator Coordinate Method ◽  
Angular Momentum Projection ◽  
Coordinate Method ◽  
Relativistic Mean Field ◽  
Generator Coordinate

The recently developed model of three-dimensional angular momentum projection plus generator coordinate method on top of triaxial relativistic mean-field states has been applied to study the low-lying states of 30 Mg . The effects of triaxiality on the low-energy spectra and E 0 and E 2 transitions are examined.

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