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Transient growth in turbulent particle-laden channel flow

Acta Mechanica Sinica 2020年第1期36卷 1-11页

作者： Yang Song Chunxiao Xu Weixi Huang Lili Wang Institute of Applied Physics and Computational Mathematics Beijing100094China AML Department of Engineering MechanicsTsinghua UniversityBeijing100084China

Linear transient growth of optimal perturbations in particle-laden turbulent channel flow is investigated in this *** problem is formulated in the framework of a Eulerian-Eulerian approach,employing two-way coupling between fine particles and fluid *** model is first validated in laminar cases,after which the transient growth of coherent perturbations in turbulent channel flow is investigated,where the mean particle concentration distribution is obtained by direct numerical *** is shown that the optimal small-scale structures for particles are streamwise streaks just below the optimal streamwise velocity streaks,as was previously found in numerical simulations of particle-laden channel *** indicates that the optimal growth of perturbations is a dominant mechanism for the distribution of particles in the near-wall *** current study also considers the transient growth of small-and large-scale perturbations at relatively high Reynolds numbers,which reveals that the optimal large-scale structures for particles are in the near-wall region while the optimal large-scale structures for fluid enter the outer region.

关键词： Optimal transient growth Wall turbulence Coherent structures Particle-laden turbulence

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Pionic and radiative transitions from Tc+s¯0(2900) to D+s1(2460) as a probe of the structure of D+s1(2460)

arXiv

引用

arXiv 2023年

作者： Yue, Zi-Li Xiao, Cheng-Jian Chen, Dian-Yong School of Physics Southeast University Nanjing210094 China Institute of Applied Physics and Computational Mathematics Beijing100088 China Lanzhou Center for Theoretical Physics Lanzhou University Lanzhou730000 China

In this work, we evaluated the widths of the pionic and radiative transitions from the Tc+s¯0(2900) to the D+s1(2460) in the D+s1(2460) molecular frame and the D+s1(2460) charmed-strange meson frame. Our estimations demonstrate that the transition widths in the D+s1(2460) molecular frame are much larger than those in the the D+s1(2460) charmed-strange meson frame. Specifically, the ratio of the widths of Γ(Tc+s¯0(2900) → D+s1π0) and Γ(Tc+s¯0(2900) → D+(0)K0(+)) is estimated to be around 0.1 in the D+s1(2460) charmed-strange meson frame, whereas the lower limit of this ratio is 0.67 in the D+s1(2460) molecular frame. Thus, the aforementioned ratio could be employed as a tool for testing the nature of the D+s1(2460). © 2023, CC BY.

关键词： Bosons

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Unified gas-kinetic wave-particle methods IV: multi-species gas mixture and plasma transport

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Advances in Aerodynamics 2021年第1期3卷 186-216页

作者： Chang Liu Kun Xu Department of Mathematics Hong Kong University of Science and TechnologyHong KongChina Institute of Applied Physics and Computational Mathematics Beijing 100088China Shenzhen Research Institute Hong Kong University of Science and TechnologyShenzhen 518057China.

In this paper,we extend the unified gas-kinetic wave-particle(UGKWP)methods to the multi-species gas mixture and multiscale plasma *** construction of the scheme is based on the direct modeling on the mesh size and time step scales,and the local cell’s Knudsen number determines the flow *** proposed scheme has the multiscale and asymptotic complexity diminishing *** multiscale property means that according to the cell’s Knudsen number the scheme can capture the non-equilibrium flow physics when the cell size is on the kinetic mean free path scale,and preserve the asymptotic Euler,Navier-Stokes,and magnetohydrodynamics(MHD)when the cell size is on the hydrodynamic scale and is much larger than the particle mean free *** asymptotic complexity diminishing property means that the total degrees of freedom of the scheme reduce automatically with the decreasing of the cell’s Knudsen *** the continuum regime,the scheme automatically degenerates from a kinetic solver to a hydrodynamic *** the UGKWP,the evolution of microscopic velocity distribution is coupled with the evolution of macroscopic variables,and the particle evolution as well as the macroscopic fluxes is modeled from a time accumulating solution of kinetic scale particle transport and collision up to a time step *** plasma transport,the current scheme provides a smooth transition from particle-in-cell(PIC)method in the rarefied regime to the magnetohydrodynamic solver in the continuum *** the continuum limit,the cell size and time step of the UGKWP method are not restricted by the particle mean free path and mean collision *** the highly magnetized regime,the cell size and time step are not restricted by the Debye length and plasma cyclotron *** multiscale and asymptotic complexity diminishing properties of the scheme are verified by numerical tests in multiple flow regimes.

关键词： Unified gas-kinetic wave-particle method Multiscale modeling Gas mixture Plasma transport

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Non-LTE ionization potential depression model for warm and hot dense plasma

arXiv

引用

arXiv 2023年

作者： Wu, Chensheng Zhou, Fuyang Wu, Yong Yan, Jun Gao, Xiang Wang, Jianguo Institute for Applied Physics and Computational Mathematics Beijing100088 China Faculty of Science Kunming University of Science and Technology Kunming650500 China

For warm and hot dense plasma (WHDP), the ionization potential depression (IPD) is a key physical parameter in determining its ionization balance, therefore a reliable and universal IPD model is highly required to understand its microscopic material properties and resolve those existing discrepancies between the theoretical and experimental results. However, the weak temperature dependence of the nowadays IPD models prohibits their application through much of the WHDP regime, especially for the non-LTE dense plasma produced by short-pulse laser. In this work, we propose a universal non-LTE IPD model with the contribution of the inelastic atomic processes, and found that three-body recombination and collision ionization processes become important in determining the electron distribution and further affect the IPD in warm and dense plasma. The proposed IPD model is applied to treat the IPD experiments available in warm and hot dense plasmas and excellent agreements are obtained in comparison with those latest experiments of the IPD for Al plasmas with wide-range conditions of 70-700 eV temperature and 0.2-3 times of solid density, as well as a typical non-LTE system of hollow Al ions. We demonstrate that the present IPD model has a significant temperature dependence due to the consideration of the inelastic atomic processes. With the low computational cost and wide range applicability of WHDP, the proposed model is expected to provide a promising tool to study the ionization balance and the atomic processes as well as the related radiation and particle transports properties of a wide range of WHDP. Copyright © 2023, The Authors. All rights reserved.

关键词： Ionization potential

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SHARP POINTWISE CONVERGENCE ON THE SCHRÖDINGER OPERATOR ALONG ONE CLASS OF CURVES

arXiv

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arXiv 2023年

作者： Cao, Zhenbin Miao, Changxing School of Mathematical Sciences Beijing Normal University Beijing100875 China Institute of Applied Physics and Computational Mathematics Beijing100088 China

Almost everywhere convergence on the solution of Schrödinger equation is an important problem raised by Carleson, which was essentially solved by Du-Guth-Li [10] and Du-Zhang [12]. In this note, we obtain the sharp pointwise convergence on the Schrödinger operator along one class of *** Codes 42B25, 35B41 Copyright © 2023, The Authors. All rights reserved.

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Inverted pin beams for robust propagation through atmospheric turbulence

Inverted pin beams for robust propagation through atmospheri...

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2024 Conference on Lasers and Electro-Optics, CLEO 2024

作者： Droulias, Sotiris Loulakis, Michalis Papazoglou, Dimitris G. Tzortzakis, Stelios Chen, Zhigang Efremidis, Nikolaos K. Institute of Applied and Computational Mathematics Foundation for Research and Technology - Hellas Crete Heraklion70013 Greece Department of Digital Systems University of Piraeus Piraeus18534 Greece Institute of Electronic Structure and Laser Foundation for Research and Technology - Hellas P.O. Box 1527 Crete Heraklion71110 Greece Department of Materials Science and Technology University of Crete Crete Heraklion700 13 Greece MOE Key Laboratory of Weak-Light Nonlinear Photonics TEDA Applied Physics Institute School of Physics Nankai University Tianjin300457 China Collaborative Innovation Center of Extreme Optics Shanxi University Shanxi Taiyuan030006 China Department of Applied Mathematics University of Crete Heraklion71409 Greece

We introduce a new class of beams the "inverted pin beams". We show that in atmospheric turbulence inverted pin beams outperform (have reduced scintillations) other classes of beams in moderate to strong flu... 详细信息

ISBN: (纸本)9781957171395

关键词： Laser beams

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Strongly perturbed state-selective charge exchange between slow Ar8+ and He

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Physical Review Research 2023年第2期5卷 023123-023123页

作者： R. T. Zhang J. W. Gao Y. W. Zhang D. L. Guo Y. Gao X. L. Zhu J. W. Xu D. M. Zhao S. Yan S. Xu S. F. Zhang Y. Wu J. G. Wang X. Ma Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 People's Republic of China University of Chinese Academy of Sciences Beijing 100049 People's Republic of China School of Physics Hangzhou Normal University Hangzhou 311121 People's Republic of China HEDPS Center of Applied Physics and Technology Peking University 100871 Beijing People's Republic of China Key Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Beijing 100088 People's Republic of China

We report an experimental and theoretical study of state-selective charge exchange processes in Ar8+ on He collisions at 1 and 3 keV/amu, benchmarking the fundamental electron capture dynamics under strong perturbations. The quantum-state selectivity has been experimentally resolved for one 1s electron of He capture into 4s, 4p, 4d+4f, and 5s states of Ar7+ ion along with the corresponding scattering angle differential cross sections. By comparing to theoretical calculations with a two-active-electron semiclassical asymptotic-state close-coupling approach, we are able to verify the important role of electronic correlations during the collisions and that the impact parameter sensitive transition probability significantly mediates the state-selective specifics.

关键词： Atomic & molecular collisions Charge-transfer collisions Scattering of atoms, molecules, clusters & ions

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Molecular opacities of low-lying states of oxygen molecule

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Chinese physics B 2020年第2期29卷 206-212页

作者： Gui-Ying Liang Yi-Geng Peng Rui Li Yong Wu Jian-Guo Wang Institute of Applied Physics and Computational Mathematics Beijing 100088China HEDPS Center for Applied Physics and TechnologyPeking UniversityBeijing 100084China Department of Physics College of ScienceQiqihar UniversityQiqihar 161006China

The X^3Σg^-,A^'3△u,A^3Σ^u+,1^3Πg,and B^3Σu^-electronic states of oxygen molecule(O2)are calculated by the multiconfiguration self-consisted filed(MRCI)+Q method with the scalar relativistic correction and core-valence correlation *** obtained spectroscopic constants of the low-lying bound states are in excellent agreement with *** on the accurately calculated structure parameters,the opacities of the oxygen molecule at the temperatures of 1000 K,2000 K,2500 K,and 5000 K under a pressure of 100 atm(1 atm=1.01325×10^5 Pa)and the partition functions between 10 K and 10^4 K are *** is found that with the increase of temperature,the opacities for transitions in a long wavelength range are enlarged because of the larger population on excited electronic states at the higher temperatures.

关键词： oxygen molecule transition dipole moments opacities

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Effects of electron-electron interactions in the Yu-Shiba-Rusinov lattice model

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Physical Review B 2023年第17期107卷 174522-174522页

作者： Valerii Kachin Teemu Ojanen Jose L. Lado Timo Hyart Department of Applied Physics Aalto University 02150 Espoo Finland Faculty of Mathematics Informatics and Mechanics University of Warsaw Banacha 2 02-097 Poland Computational Physics Laboratory Physics Unit Faculty of Engineering and Natural Sciences Tampere University FI-33014 Tampere Finland Helsinki Institute of Physics P.O. Box 64 FI-00014 Finland

In two-dimensional superconductors, Yu-Shiba-Rusinov bound states, induced by the magnetic impurities, extend over long distances giving rise to a long-range hopping model supporting a large number of topological phases with distinct Chern numbers. Here, we study how the electron-electron interactions affect, on a mean-field level, the selection of the realized Chern numbers and the magnitudes of the topological energy gaps in this model. We find that, in the case of an individual choice of the model parameters, the interactions can enhance or reduce the topological gap as well as cause topological phase transitions because of the complex interplay of superconductivity, magnetism, and the large spatial extent of the Yu-Shiba-Rusinov states. By sampling a large number of realizations of Yu-Shiba-Rusinov lattice models with different model parameters, we show that, statistically, the interactions have no effect on the realized Chern numbers and typical magnitudes of the topological gaps. However, the interactions substantially increase the likelihood of the largest topological gaps in the tails of the energy gap distribution in comparison to the noninteracting case.

关键词： Impurities in superconductors Magnetic texture Spin-orbit coupling Superconductivity Topological materials Topological phase transition Topological superconductors Bogoliubov-de Gennes equations Mean field theory Methods in superconductivity

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A hybrid subcell-remapping algorithm for staggered multi-material arbitrary Lagrangian-Eulerian methods

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applied mathematics and Mechanics(English Edition) 2019年第10期40卷 1487-1508页

作者： Haihua YANG Ping ZHANG Institute of Applied Physics and Computational Mathematics

A new flux-based hybrid subcell-remapping algorithm for staggered multimaterial arbitrary Lagrangian-Eulerian (MMALE) methods is presented. This new method is an effective generalization of the original subcell-remapping method to the multi-material regime (LOUBERE, R. and SHASHKOV,M. A subcell remapping method on staggered polygonal grids for arbitrary-Lagrangian-Eulerian methods. Journal of computational physics, 209, 105–138 (2005)). A complete remapping procedure of all fluid quantities is described detailedly in this paper. In the pure material regions, remapping of mass and internal energy is performed by using the original subcell-remapping method. In the regions near the material interfaces, remapping of mass and internal energy is performed with the intersection-based fluxes where intersections are performed between the swept regions and pure material polygons in the Lagrangian mesh, and an approximate approach is then introduced for constructing the subcell mass fluxes. In remapping of the subcell momentum, the mass fluxes are used to construct the momentum fluxes by multiplying a reconstructed velocity in the swept region. The nodal velocity is then conservatively recovered. Some numerical examples simulated in the full MMALE regime and several purely cyclic remapping examples are presented to prove the properties of the remapping method.

关键词： multi-material arbitrary Lagrangian-Eulerian (MMALE) subcell remapping method hybrid remapping method

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