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DEPTH-AVERAGED 2-D CALCULATION OF FLOW AND sEDIMENT TRANsPORT IN CURVED CHANNELs

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International Journal of sediment Research 2004年第4期19卷 241-257页

作者： sam s. y. wang Director Distinguished Professor Ms 38677 National Center for Computational Hydroscience and Engineering The University of Mississippi UsA

The helical flow significantly affects the flow, sediment transport and morphological evolution in curved channels. A semi-empirical formula is proposed to determine the cross-stream distribution of the helical flow intensity in the developed regions of a channel bend. It is then used to evaluate the dispersion terms in the depth-averaged 2-D momentum equations and suspended-load transport equation as well as the bed-load transport angle, thus enhancing the depth-averaged 2-D model to account for the effect of helical flow. The tests in several experimental and field cases show that the enhanced depth-averaged 2-D model can much more reasonably predict the shifting of main flow from inner bank to outer bank, the erosion along outer bank and deposition along inner bank than the depth-averaged 2-D model without considering this effect.

关键词： secondary flow Channel bends Dispersion Unsteady flow sediment transport Two- dimensional model Finite volume method

Two-dimensional numerical and eco-toxicological modeling of chemical spills

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Frontiers of Environmental science & Engineering 2009年第2期3卷 178-185页

作者： suiliang HUANG yafei JIA sam s.y.wang Numerical simulation Group for Water Environment Key Laboratory of Pollution Processes and Environmental Criteria of Ministry of EducationTianjin Key Laboratory of Environmental Remediation and Pollution ControlCollege of Environmental Science and EngineeringNankai UniversityTianjin 300071China National Center for Computational Hydroscience and Engineering The University of MississippiOxfordMS 38677USA

The effects of chemical spills on aquatic nontarget organisms were evaluated in this *** on a review of three types of current eco-toxicological models of chemicals,i.e.,ACQUATOX model of the Us-EPA,Hudson River Model of PCBs,and critical body residual(CBR)model and dynamic energy budget(DEBtox)model,this paper presents an uncoupled numerical ecotoxicological *** transport and transformation of spilled chemicals were simulated by a chemical transport model(including flow and sediment transport),and the mortalities of an organism caused by the chemicals were simulated by the extended threshold damage model,*** to extreme scarcity of data,this model was applied to two hypothetical cases of chemical spills happening upstream of a *** analysis and simulated results indicated that this model is capable of reasonably predicting the acute effects of chemical spills on aquatic ecosystems or organism killings.

关键词： chemical spills acute effects aquatic ecosystem eco-toxicological modeling

Numerical simulations of morphological changes in barrier islands induced by storm surges and waves using a supercritical flow model

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Frontiers of structural and Civil Engineering 2014年第1期8卷 57-68页

作者： soumendra Nath KUIRy yan DING sam s y wang Environmental & Water Resources Engineering Division Department of Civil Engineering lndian Institute of Technology Madras Tamil Nadu 600036 India National Center for Computational Hydroscienee and Engineering The University of Mississippi University MS 38677 USA

In this paper, an advanced explicit finite volume flow model in two-dimensions is presented for simulating supercritical coastal flows and morphological changes in a tidal/coastal inlet and barrier islands due to storm surges and waves. This flow mode/ is coupled with existing wave-action mode/and sediment transport mode/. The resulting integrated coastal process model is capable of simulating flows induced by extreme conditions such as waves, surge tides, river flood flows, etc., and morphological changes induced by rapid coastal currents and waves. This developed supercritical ftow model is based on the solution of the conservative form of the nonlinear shallow water equations with the effects of the Coriolis force, uneven bathymetry, wind stress, and wave radiation stresses. The forward Euler scheme is used for the unsteady term; and the convective term is discretized using the Godunov-type shock- capturing scheme along with the HLL Riemann solver on non-uniform rectilinear grids. The accuracy of the developed model is investigated by solving an experimental dam-break test case. Barrier island breaching, overflow and overwash due to severe storm attack are simulated and the predicted morphological changes associated to the events are analyzed to investigate the applicability of the model in a coast where all the physical forces are present.

关键词： coastal inlet coastal process modeling supercritical flow sediment transport barrier islands

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Investigations of nuclear chirality at iThemba LABs

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Frontiers of physics 2024年第2期19卷 7-38页

作者： R.A.Bark E.A.Lawrie C.Liu s.y.wang iThemba Laboratory for Accelerator Based sciences National Research FoundationP.O.Box 722Somerset-West 7129South Africa Department of Physics University of the Western CapePrivate Bag X177535BellvilleSouth Africa shandong Provincial Key Laboratory of Optical Astronomy and solar-Terrestrial Environment Institute of Space SciencesShandong UniversityWeihai 264209China

Progress in the studies of chirality in atomic nuclei at iThemba LABs is *** regions of chirality,around mass 80 and 190 have been discovered using the AFRODITE array,specifically in the nuclei^(74)As,^(78,80,82)Br,^(81)Kr,and^(193,194,198)*** phenomena have been observed,including multiple chiral bands in the same nucleus,the coexistence of octupole correlations and nuclear chirality,and the coexistence of pseudo spin and nuclear *** best example of chiral degeneracy to date was found in ^(194)*** level scheme of ^(106)Ag has been revisited and interpreted in terms of two-and four-quasiparticle *** using the particle-rotor model have shown that the fingerprints of chirality in the two-quasiparticle system only can occur in an idealised model *** systems with a higher number of quasiparticles,the calculations showed that nuclear chirality can persist.

关键词： chirality high-spin states particle-rotor model

Ren-integrable and ren-symmetric integrable systems

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Communications in Theoretical Physics 2024年第3期76卷 62-69页

作者： s y Lou school of Physical science and Technology Ningbo UniversityNingbo315211China

A new type of symmetry,ren-symmetry,describing anyon physics and corresponding topological physics,is ***-symmetry is a generalization of super-symmetry which is widely applied in super-symmetric physics such as super-symmetric quantum mechanics,super-symmetric gravity,super-symmetric string theory,super-symmetric integrable systems and so *** and Grassmann numbers are,in some sense,dual conceptions,and it turns out that these conceptions coincide for the ren situation,that is,a similar conception of ren-number(R-number)is devised for *** particular,some basic results of the R-number and ren-symmetry are exposed which allow one to derive,in principle,some new types of integrable systems including ren-integrable models and ren-symmetric integrable *** examples of ren-integrable KdV-type systems and ren-symmetric KdV equations are explicitly given.

关键词： symmetries integrable systems anyon physics extended supersymmetry ren-symmetry

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Effect of Eu3+,Bi3+,and Li+ doping on luminescent property of GdNbO4

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Journal of Rare Earths 2024年第1期42卷 66-75页

作者： s.W.Wi y.s.Lee Department of Physics and Integrative Institute of Basic sciences Soongsil University

We investigated the emission properties of Eu3+-doped GdNbO4-based oxide phosphors,aiming at improving the Eu3+emission by codoping of Bi3+and Li+.Eu3+singly doped,Eu3+and Bi3+doubly doped,and Eu3+,Bi3+,and Li+triply doped GdNbO4were prepared using a high-temperature solid-state reaction *** red-orange emissions from Eu3+in the singly doped samples are significantly improved by the codoping of Bi3+,mainly due to the energy transfer from Bi3+to Eu3+.The additional codoping of Li+is found to increase the Eu3+emission *** improvement might be attributed to the increase in the photoluminescent quantum yield originating from larger grain sizes and better crystallinity.A detailed analysis of the X-ray diffraction pattern and the asymmetric ratio estimated from the photoluminescence spectra show that the local lattice environment around Eu3+in GdNbO4does not change significantly with the codoping of Bi3+and Li+.Our results indicate that Li+doping is a promising way to improve the emission properties of rare-earth ion-doped GdNbO4phosphors.

关键词： Eu 3+ GdNbO 4 Codoping of Li + Photoluminescence sensitizer Rare earths

Electron kinetic effects in back-stimulated Raman scattering bursts driven by broadband laser pulses

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Matter and Radiation at Extremes 2024年第4期9卷 54-67页

作者： Q.K.Liu L.Deng Q.wang X.Zhang F.Q.Meng y.P.wang y.Q.Gao H.B.Cai s.P.Zhu Graduate school China Academy of Engineering PhysicsBeijing 100088China Institute of Applied Physics and Computational Mathematics Beijing 100094China school of Nuclear science and Technology University of Science and Technology of ChinaHefei 230026China shanghai Institute of Laser Plasma Shanghai 201800China HEDPs Center for Applied Physics and TechnologyPeking UniversityBeijing 100871China school of Physics Zhejiang UniversityHangzhou 310027China

We examine electron kinetic effects in broadband-laser-driven back-stimulated Raman scattering(BsRs)bursts using particle-in-cell *** bursts occur during the nonlinear stage,causing reflectivity spikes and generating large numbers of hot ***-duration simulations are performed to observe burst events,and a simplified model is developed to eliminate the interference of the broadband laser’s random intensity *** the simplified model,we isolate and characterize the spectrum of electron plasma *** spectrum changes from a sideband structure to a turbulence-like structure during the burst.A significant asymmetry in the spectrum is *** asymmetry is amplified and transferred to electron phase space by high-intensity broadband laser pulses,leading to violent vortex-merging and generation of hot *** proportion of hot electrons increases from 6.76%to 14.7%during a single violent burst *** demonstrate that kinetic effects profoundly influence the BsRs evolution driven by broadband lasers.

关键词： scattering kinetic simplified

DEPTH-AVERAGE ANALysIs OF HysTEREsIs BETWEEN FLOW AND sEDIMENT TRANsPORT UNDER UNsTEADy CONDITIONs

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International Journal of sediment Research 2006年第2期21卷 101-112页

作者： Mustafa ALTINAKAR sam s.y.wang National Center for Computational Hydroscience and Engineering The University of Mississippi MS 38677 USA Res. Prof. National Center for Computational Hydroscience and Engineering The University of Mississippi MS 38677 USA Prof.

A depth-averaged two-dimensional model has been established to simulate unsteady flow and sediment transport in streams. The difference in flow and sediment velocities is considered. It has been found that the depth-averaged suspended-sediment velocity and the bed-load velocity are smaller than the depth-averaged flow velocity, inducing a time lag between water and sediment transport. The significance of this time lag increases as the sediment size increases. The exchange between the moving sediment and the bed material, which may induce a spatial lag, is modeled by a non-equilibrium transport approach. Tests using laboratory and field measurements have shown that the established model is capable of capturing the hysteresis between flow and sediment transport under unsteady conditions. It is demonstrated that the hysteresis is larger when the hydrograph has steeper rising and falling limbs, and the time delay increases downstream.

关键词： Hysteresis Temporal and spatial lags Unsteady flow sediment transport Depth- averaged 2-D model Non-equilibrium transport

A sIMPLIFIED APPROACH TO MODELING 3D sEDIMENT-LADEN TURBULENT FLOWs

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International Journal of sediment Research 1996年第1期 54-80页

作者： Donghuo ZHOU and sam s.y.wang

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关键词： Numerical model suspended sediment Turbulence Eddy viscosity Flow perturbation