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Development of naoe-FOAM-SJTU solver based on OpenFOAM for marine hydrodynamics

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Journal of Hydrodynamics 2019年第1期31卷 1-20页

作者： Jian-hua Wang Wei-wen Zhao De-cheng Wan Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration School of Naval ArchitectureOcean and Civil EngineeringState Key Laboratory of Ocean EngineeringShanghai Jiao Tong UniversityShanghai 200240China

A CFD solver naoe-FOAM-SJTU (The abbreviation naoe stands for naval architecture and ocean engineering) is developed based on the open source platform OpenFOAM with the purpose of simulating various marine hydrodynamic problems.In the present paper,self-developed modules,i.e.,wave generation and absorption,6 degrees of freedom motion,mooring system,dynamic overset grid,fluid-structure interaction,unsteady actuator line model,implemented on the open source platform OpenFOAM are introduced to illustrate the development of the marine hydrodynamics CFD solver.Furthermore,extensive simulations of marine hydrodynamic problems using the developed modules are conducted and validated by available experimental data.It has been proved that the CFD solver naoe-FOAM-SJTU is suitable and reliable in predicting the complex viscous flow around ship and offshore structures.Efficiency and accuracy need to be focused in the future development of the present CFD solver.

关键词： Marine hydrodynamics fluid-structure interaction overset grid naoe-FOAM-SJTU solver OpenFOAM

A numerical study for WENO scheme-based on different lattice Boltzmann flux solver for compressible flows

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Acta Mechanica Sinica 2018年第6期34卷 995-1014页

作者： You Li Xiao-Dong Niu Hai-Zhuan Yuan Adnan Khan Xiang Li College of Engineering Shantou UniversityShantou 515063China School of Mathematics and Computational Science Xiangtan UniversityXiangtan 411105China

In this paper,the finite difference weighted essentially non-oscillatory (WENO) scheme is incorporated into the recently developed four kinds of lattice Boltzmann flux solver (LBFS) to simulate compressible flows,including inviscid LBFS Ⅰ,viscous LBFS Ⅱ,hybrid LBFS Ⅲ and hybrid LBFS Ⅳ.Hybrid LBFS can automatically realize the switch between inviscid LBFS Ⅰ and viscous LBFS Ⅱ through introducing a switch function.The resultant hybrid WENO-LBFS scheme absorbs the advantages of WENO scheme and hybrid LBFS.We investigate the performance of WENO scheme based on four kinds of LBFS systematically.Numerical results indicate that the devopled hybrid WENO-LBFS scheme has high accuracy,high resolution and no oscillations.It can not only accurately calculate smooth solutions,but also can effectively capture contact discontinuities and strong shock waves.

关键词： WENO scheme Hybrid Lattice Boltzmann flux solver Compressible inviscid flows Contact discontinuities Shock waves

A FORMAL SYSTEMS APPROACH TO solver DESIGN-HILL CLIMBING METHOD WITH PUSH DOWN STACK

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Systems Science and Systems Engineering 2003年第2期12卷 138-158页

作者： YasuhikoTAKAHARA YongmeiLIU YoshioYANO DepertmentofManagementInformationScience ChibaInstituteofTechnology2-17-1TsudanumaNarashinoChibaJapan CollegeofBusiness CentralSouthUniversityChangsha410083P.R.China

This paper presents a formal approach to design of a solver of an intelligent management information system and its implementation. The approach implies set theoretic modeling based on the general systems concepts and implementation in the extProlog.There are research efforts which attack (optimization) problems using the set theory and logics. Furthermore, they use logic programming languages for their implementation. Although their methods look quite similar to the approach of this paper, there are clear differences between them. This paper is interested in exploration of the solving system rather than algorithms.The paper first presents a design and implementation procedure of a solver. Then, classification of problems is discussed. The least structured class of the classification is the target of this paper. A data mining system is an example of the class.Formal theories are derived for the design procedure assuming the least structured case. A solving strategy, which is called a hill climbing method with a push down stack, is proposed on the theories.A data mining system is used as an example to illustrate the results.Finally, a full implementation in extProlog is presented for the data mining system.

关键词： solver hill climbing push down automaton systems approach set theory Prolog

1D study of the detonation phenomenon and its influence on the interior ballistics of the combustion light gas gun

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Defence Technology（防务技术） 2020年第2期16卷 341-347页

作者： Fei Zhou Ning Liu Xiang-yan Zhang Xiu-dong You School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094JiangsuChina Troops 91388 of PLA Zhanjiang 524022GuangdongChina

One-dimensional simulations with a detailed hydrogen-oxygen reaction mechanism have been performed to investigate detonation phenomenon in a combustion light gas gun(CLGG).Convection fluxes of the Navier-Stokes equations are solved using the WAF(weighted average flux)scheme HLLC Riemann solver.A high resolution fifth-order WENO scheme for the variable extrapolation at the volume interface and a fourth-order Runge-Kutta scheme for the time advancement are used.Validation tests of the stoichiometric hydrogen-oxygen deflagration to detonation transition process shows good agreement between the computed results and the analytical and documented solutions,demonstrating the reliability on the detonation simulation of the current scheme.Simulation results of the interior ballistic process of the CLGG show that the flame propagation experiences three distinct stages.The blast detonation wave causes a high-pressure shock and hazardous oscillations in the chamber and makes the projectile accelerate with fluctuations,but has only a small improvement to the muzzle velocity.

关键词： Riemann solver WAF Combustion light gas gun Detonation

Transversal effects of high order numerical schemes for compressible fluid flows

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Applied Mathematics and Mechanics(English Edition) 2019年第3期40卷 343-354页

作者： Xin LEI Jiequan LI School of Mathematical Sciences Beijing Normal University Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Center for Applied Physics and Technology Peking University

Finite volume schemes for the two-dimensional(2D) wave system are taken to demonstrate the role of the genuine dimensionality of Lax-Wendroff flow solvers for compressible fluid flows. When the finite volume schemes are applied, the transversal variation relative to the computational cell interfaces is neglected, and only the normal numerical flux is used, thanks to the Gauss-Green formula. In order to offset such defects, the Lax-Wendroff flow solvers or the generalized Riemann problem(GRP) solvers are adopted by substituting the time evolution of flows into the spatial variation. The numerical results show that even with the same convergence rate, the error by the GRP2D solver is almost one ninth of that by the multistage Runge-Kutta(RK) method.

关键词： transversal effect generalized Riemann problem(GRP)solver Lax-Wendroff flow solver wave system

Numerical investigation of the effects of aquatic plants on wind-induced currents in Taihu Lake in China

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Journal of Hydrodynamics 2019年第4期31卷 778-787页

作者： Tian-ping Xu Ming-liang Zhang Hcng-zhi Jiang Jun Tang Hong-xing Zhang Hui-ting Qiao School of Ocean Science and Environment Dalian Ocean University Dalian 116023 China National Marine Environmental Monitoring Center Dalian 116023 China State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116023 China

Shallow lakes are an important part of the earth's water circulation system, and many factors may impact the evolution of the lake water circulation, including the wind, the topography, the human activities, and the aquatic plants. This paper proposes a depth-averaged 2-D hydrodynamic model to investigate the interaction of the wind-induced current and the aquatic plant in the lake. The model is based on the generalized shallow water equations solved by an explicit finite volume method with unstructured triangular grids. The drag force of the vegetation is considered into the momentum equations as the source term. Remote sensing techniques are applied to evaluate the aquatic vegetation in the Taihu Lake, China, based on Landsat TM satellite images. The study model is then used to simulate the characteristics of the wind-induced currents in the Taihu Lake, without and with the vegetation effects. The simulation results are in good agreement with the field measurements, demonstrating that the aquatic plants significantly affect the magnitude of the velocity and the flow circulation induced by the wind in the Taihu Lake. In addition, a sensitivity analysis reveals that the plant parameters (the density and the drag force coefficient) are significant factors influencing the velocity and the structure of the currents in the Taihu Lake.

关键词： Finite volume method Roe solver shallow lake wind-induced current aquatic plant

Excel as an Educational Platform for Design Analyses of Fluid-Thermal Systems

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World Journal of Engineering and Technology 2022年第2期10卷 434-443页

作者： Mohamed M. El-Awad Mohammed S. Al-Saidi Engineering Department University of Technology and Applied Sciences Suhar Oman

Equipped with its solver and-in and VBA, Microsoft Excel makes an ideal educational platform for design analyses of fluid-thermal systems. This paper illustrates this capability by considering a common type of these systems;which is the double-pipe heat exchanger. While solver is used for the optimisation analysis, VBA is used for the development of a user-defined function (UDF) that determines the optimum standard-pipe size for the system.

关键词： Fluid-Thermal Systems Design Optimisation Excel solver VBA

Optimization Model: Resource Distribution for Risk Factors of Type 2 Diabetes Prevention

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Open Journal of Optimization 2023年第1期12卷 1-9页

作者： Kanika Misra Stevens Institute of Technology Hoboken USA

Type 2 Diabetes, a lifestyle disease, can be prevented/delayed by adopting a healthy lifestyle. Awareness of the same amongst the citizens can be one of the best ways to initiate a decline in the positive census of the disease. We use this paper to illustrate an optimization model where the budget can be distributed based on the census data of the risk factors involved. It uses a non-linear programming model and can easily be modified into a linear one. The alternative options and constraints too, are mentioned in the paper. The results show that the mid-western states need more share of the allocation based on risk factors. The model distributes the percentage of the budget allocated to different states based on a fixed risk factor constraint.

关键词： Optimization Algorithms Application Based Solution Diabetes Resources solver Excel Objective Function

Analysis of Unsteady Flow over Offshore Wind Turbines in Combination with Different types of Foundations

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Journal of Marine Science and Application 2017年第2期16卷 199-207页

作者： Israa Alesbe Moustafa Abdel-Maksoud Sattar Aljabair Institute for Fluid Dynamics and Ship Theory (M8) Hamburg University of Technology (TUHH) D-21073 Hamburg Germany Department of Mechanical Engineering University of Technology Baghdad 10066 Iraq

Environmental effects have an important influence on Offshore Wind Turbine (OWT) power generation efficiency and the structural stability of such turbines. In this study, we use an in-house Boundary Element (BEM)-panMARE code-to simulate the unsteady flow behavior of a full OWT with various combinations of aerodynamic and hydrodynamic loads in the time domain. This code is implemented to simulate potential flows for different applications and is based on a three-dimensional first-order panel method. Three different OWT configurations consisting of a generic 5 MW NREL rotor with three different types of foundations (Monopile, Tripod, and Jacket) are investigated. These three configurations are analyzed using the RANSE solver which is carried out using ANSYS CFX for validating the corresponding results. The simulations are performed under the same environmental atmospheric wind shear and rotor angular velocity, and the wave properties are wave height of 4 m and wave period of 7.16 s. In the present work, wave environmental effects were investigated firstly for the two solvers, and good agreement is achieved. Moreover, pressure distribution in each OWT case is presented, including detailed information about local flow fields. The time history of the forces at inflow direction and its moments around the mudline at each OWT part are presented in a dimensionless form with respect to the mean value of the last three loads and the moment amplitudes obtained from the BEM code, where the contribution of rotor force is lower in the tripod case and higher in the jacket case and the calculated hydrodynamic load that effect on jacket foundation type is lower than other two cases.

关键词： panel method time domain offshore wind turbine RANSE solver boundary element method unsteady flow