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A typhoon-induced storm surge numerical model with GPU acceleration based on an unstructured spherical centroidal Voronoi tessellation grid

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Acta Oceanologica Sinica 2024年第3期43卷 40-47页

作者： Yuanyong Gao Fujiang Yu Cifu Fu Jianxi Dong Qiuxing Liu National Marine Environmental Forecasting Center Beijing 100081China Key Laboratory of Marine Hazards Forecasting Ministry of Natural ResourcesBeijing 100081China

Storm surge is often the marine disaster that poses the greatest threat to life and property in coastal *** and timely issuance of storm surge warnings to take appropriate countermeasures is an important means to reduce storm surge-related *** surge numerical models are important for storm surge *** further improve the performance of the storm surge forecast models,we developed a numerical storm surge forecast model based on an unstructured spherical centroidal Voronoi tessellation(SCVT)*** model is based on shallow water equations in vector-invariant form,and is discretized by Arakawa C *** SCVT grid can not only better describe the coastline information but also avoid rigid transitions,and it has a better global consistency by generating high-resolution grids in the key areas through transition *** addition,the simulation speed of the model is accelerated by using the openACC-based GPU acceleration technology to meet the timeliness requirements of operational ensemble *** only takes 37 s to simulate a day in the coastal waters of *** newly developed storm surge model was applied to simulate typhoon-induced storm surges in the coastal waters of *** hindcast experiments on the selected representative typhoon-induced storm surge processes indicate that the model can reasonably simulate the distribution characteristics of storm *** simulated maximum storm surges and their occurrence times are consistent with the observed data at the representative tide gauge stations,and the mean absolute errors are 3.5 cm and 0.6 h respectively,showing high accuracy and application prospects.

关键词： typhoon-induced storm surge numerical model GPU acceleration unstructured grid spherical centroidal Voronoi tessellation(SCVT)

Fracture of films caused by uniaxial tensions:a numerical model

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Applied Mathematics and Mechanics(English Edition) 2023年第12期44卷 2093-2108页

作者： Chenxue JIA Zihao WANG Donghui ZHANG Taihua ZHANG Xianhong MENG School of Aeronautics and Astronautics University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Space Utilization Technology and Engineering Center for Space UtilizationChinese Academy of SciencesBeijing 100094China Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China

Surface cracks are commonly observed in coatings and *** structures with coatings are subject to stretching,opening mode cracks are likely to form on the surface,which may further lead to other forms of damage,such as interfacial delamination and substrate *** crack forms include cracks extending towards the interface and channeling across the *** this paper,a two-dimensional numerical model is proposed to obtain the structural strain energy at arbitrary crack lengths for bilayer structures under uniaxial *** energy release rate and structural stress intensity factors can be obtained accordingly,and the effects of geometry and material features on fracture characteristics are investigated,with most crack patterns being confirmed as *** proposed model can also facilitate the analysis of the stress distribution in periodic crack patterns of *** results from the numerical model are compared with those obtained by the finite element method(FEM),and the accuracy of the theoretical results is demonstrated.

关键词： surface crack numerical model stress intensity factor periodic crack finite element method(FEM)

numerical model of compressible gas flow in soil pollution control

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Journal of Environmental Sciences 2002年第2期14卷 239-244页

作者： ChenJJ WangHQ InstituteofEnvironmentalSciences StateKeyJointLaboratoryofEnvironmentalSimulationandPollutionControlBeijingNormalUniversityBeijing100875China InstituteofEnvironmentalSciences StateKeyJointLaborator

Based on the theory of fluid dynamics in porous media, a numerical model of gas flow in unsaturated zone is developed with the consideration of gas density change due to variation of air pressure. This model is characterized of its wider range of availability. The accuracy of this numerical model is analyzed through comparison with modeling results by previous model with presumption of little pressure variation and the validity of this numerical model is shown. Thus it provides basis for the designing and management of landfill gas control system or soil vapor extraction system in soil pollution control.

关键词： numerical model compressible gas landfill gas migration soil vapor extraction pollution control

A numerical model for Natural Backfill of Pipeline Trenches Subjected to Unidirectional/Oscillatory Flows

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China Ocean Engineering 2005年第2期19卷 269-286页

作者： Kervin YEOW School of Civil and Resource Engineering The University of Western AustraliaCrawley WA6009 Australia

A numerical model for the self-burial of a pipeline trench is developed. Morphological evolutions of a pipeline trench under steady-current or oscillatory-flow conditions are simulated with/without a pipeline inside the trench. The oscillatory flow in this study represents the action of waves. The two-dimensional Reynolds-averaged continuity and Navier-Stokes equations with the standard k-ε turbulence closure, as well as the sediment transport equations, are solved with the finite difference method in a curvilinear coordinate system. Both bed and suspended loads of sediment transport are included in the morphological model. Because of the lack of experimental data on the backfilling of pipeline trenches, the numerical model is firstly verified against three closely-relevant experiments available in literature. A detailed measurement of the channel migration phenomenon under steady currents is employed for the assessment of the integral performance of the model. The two experimental results from U-tube tests are used to validate the model's ability in predicting oscillatory flows. Different time-marching schemes are employed for the morphological computation under unidirectional and oscillatory conditions. It is found that vortex motions within the trench play an important role in the trench development.

关键词： numerical model backfill sediment transport offshore pipeline trench oscillatary flow

numerical model of Internal Solitary Wave Evolution on ImpermeableVariable Seabed in A Stratified Two-Layer Fluid System

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China Ocean Engineering 2006年第2期20卷 303-313页

作者： Chen-Yuan CHEN John Rong-Chung HSU Cheng-Wu CHEN Ming-Hung CHENG Department of Madne Envirorunent and Engineering National Sun Yat-sen University Kaohsiung 80424 Taiwan China School of Civil and Resource Engineering University of Western Australia WA 6009 Australia Department of Logistics Management Shu-Te University Kaohsiung 82445 Taiwan China

In the present study a numerical model developed by Lynett and Liu （2002） is modified to include density difference in a stratified two-layer fluid in a three-dimensional internal wave domain. The internal solitary wave （ISW） in the model is assumed to be weakly nonlinear and weakly dispersive, and the viscosity effects at all boundaries are ignored. The governing equations based on the Navier-Stokes and Euler equations are solved for internal solitary wave propagation over variable seabed topography. Theoretical formulations are established, from which analytical solutions are obtained, in addition to numerical results. Wave profiles from previous experimental studies are compared with the numerical results from the present analytical solutions. numerical models developed on the basis of the present analytical solutions are better than those developed by Lynett and Liu （2002）. The results of numerical modeling agree well with the experimental data.

关键词： Navier-Stokes equation nonlinearity frequency dispersion internal solitary wave numerical model

numerical model of tandem organic light-emitting diodes based on a transition metal oxide interconnector layer

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Journal of Semiconductors 2014年第4期35卷 68-76页

作者：路飞平彭应全邢永忠 College of Physics and Information Science Tianshui Normal University Institute of Microelectronics School of Physical Science and Technology Lanzhou University

By utilizing a two-step process to express the charge generation and separation mechanism of the transition metal oxides （TMOs） interconnector layer, a numerical model was proposed for tandem organic light emitting diodes （OLEDs） with a TMOs thin film as the interconnector layer. This model is valid not only for an n-type TMOs interconnector layer, but also for a p-type TMOs interconnector layer. Based on this model, the influences of different carrier injection barriers at the interface of the electrode/organic layer on the charge generation ability of interconnector layers were studied. In addition, the distribution characteristics of carrier concentration, electric field intensity and potential in the device under different carrier injection barriers were studied. The results show that when keeping one carrier injection barrier as a constant while increasing another carrier injection barrier, carri- ers injected into the device were gradually decreased, the carrier generation ability of the interconnector layer was gradually reduced, the electric field intensity at the interface of the organic/electrode was gradually enhanced, and the electric field distribution became nearly linear： the voltage drops in two light units gradually became the same. Meanwhile, the carrier injection ability decreased as another carrier injection barrier increased. The simulation re- sults agree with the experimental data. The obtained results can provide us with a deep understanding of the work mechanism of TMOs-based tandem OLEDs.

关键词： tandem organic light-emitting diodes numerical model interconnector layer transition metal oxide

A numerical model OF FLOW FIELD AND WATER QUALITY FOR TIDAL REGIONS BASED ON TRIANGULAR MESHES

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Journal of Hydrodynamics 2003年第1期15卷 23-30页

作者： HuaZu-lin XuZu-xin CollegeofEnvironmentScienceandEngineering HohaiUniversityNanjing210098China CollegeofEnvironmentScienceandEngineering TongjiUniversityShanghai200092China

In tidal areas, natural land boundary is complex and underwater topographyvaries acutely due to influence of upstream runoff and outer tide. The simulation and forecast ofwater current and mass transport play an important role in practical engineering. According to thesituation of irregular natural boundaries in tidal region, unsturctured triangular grid arrangementis applied to suit for complex conditions. A finite difference method with alternating directionalimplicit scheme for triangular grid is established in this paper. The model has been applied incalculation of flow and concentration fields for Nantong reach of the Yangtze River. It is satisfiedthat the calculated values are in agreement with observed data.

关键词： numerical model tidal regions water quality triangular meshes

A numerical model for air concentration distribution in self-aerated open channel flows

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Journal of Hydrodynamics 2015年第3期27卷 394-402页

作者：卫望汝邓军张法星田忠 State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University

The self-aeration in open channel flows, called white waters, is a phenomenon seen in spillways and steep chutes. The air distribution in the flow is always an important and fundamental issue. The present study develops a numerical model to predict the air concentration distribution in self-aerated open channel flows, by taking the air-water flow as consisting of a low flow region and an upper flow region. On the interface between the two regions, the air concentration is 0.5. In the low flow region where air concentration is lower than 0.5, air bubbles diffuse in the water flow by turbulent transport fluctuations, and in the upper region where air concentration is higher than 0.5, water droplets and free surface roughness diffuse in the air. The air concentration distributions obtained from the diffusion model are in good agreement with measured data both in the uniform equilibrium region and in the self-aerated developing region. It is demonstrated that the numerical model provides a reasonable description of the self-aeration region in open channel flows.

关键词： self-aeration air concentration open channel flows turbulence diffusion numerical model

A SEMI-IMPLICIT 3-D numerical model USING SIGAM-COORDINATE FOR NON-HYDROSTATIC PRESSURE FREE-SURFACE FLOWS

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Journal of Hydrodynamics 2011年第2期23卷 212-223页

作者： HU De-chao FAN Bei-lin WANG Guang-qian ZHANG Hong-wu State Key Laboratory of Hydroscience and Engineering Tsinghua University Beijing 100084 China Yangtze River Scientific Research Institute Wuhan 430010 China

A 3-D numerical formulation is proposed on the horizontal Cartesian, vertical sigma-coordinate grid for modeling non-hydrostatic pressure flee-surface flows. The pressure decomposition technique and 0 semi-implicit method are used, with the solution procedure being split into two steps. First, with the implicit parts of non-hydrostatic pressures excluded, the provisional velocity field and free surface are obtained by solving a 2-D Poisson equation. Second, the theory of the differential operator is employed to derive the 3-D Poisson equation for non-hydrostatic pressures, which is solved to obtain the non-hydrostatic pressures and to update the provisional velocity field. When the non-orthogonal sigma-coordinate transformation is introduced, additional terms come into being, resulting in a 15-diagonal, diagonally dominant but unsymmetric linear system in the 3-D Poisson equation for non-hydrostatic pressures. The Biconjugate Gradient Stabilized （BiCGstab） method is used to solve the resulting 3-D unsymmetric linear system instead of the conjugate gradient method, which can only be used for symmetric, positive-definite linear systems. Three test cases are used for validations. The successful simulations of the small-amplitude wave, a supercritical flow over a ramp and a turbulent flow in the open channel indicate that the new model can simulate well non-hydrostatic flows, supercritical flows and turbulent flows.

关键词： 3-D numerical model non-hydrostatic sigma-coordinate semi-implicit pressure-splitting