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Assessment of ship maneuvering simulation with different propeller models

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Journal of Hydrodynamics 2022年第3期34卷 422-433页

作者： Ganbo Deng Patrick Queutey Jeroen Wackers Michel Visonneau Emmanuel Guilmineau Alban Leroyer LHEEA Lab Ecole Centrale de NantesNantesFrance

This paper is devoted to the assessment of ship maneuvering simulation using different propeller models with the focus on a simplified propeller model that represents the action of the propeller by body force and uses propeller performance curve to determine propeller loading during ship *** are also performed with an actual propeller approach with which the propeller rotation is simulated directly with the Reynolds averaged Navier-Stokes equation(RANSE)*** time accurate simulations using sliding grid and rotating frame approximations have been performed for *** zigzag and turning circle maneuvers in calm water have been simulated for two different ship models,namely the ONR tumblehome(ONRT)test case and the KRISO(Korea Research Institute of Ship and Ocean)Container Ship(KCS)test *** ship motion is compared with measurement data to assess the accuracy of the numerical prediction using RANSE computations with different propeller models.

关键词： Ship zigzag and turning circle motion simplified propeller model with body force actual propeller approach

Theoretical and numerical investigation of HF elastic wave propagation in two-dimensional periodic beam lattices

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Acta Mechanica Sinica 2013年第6期29卷 783-798页

作者： B.Tie B.Y.Tian D.Aubry Laboratory MSSMat(UMR-CNRS 8579) Ecole Centrale ParisGrande Voie des Vignes92295 Chatenay-Malabry CedexFrance

The elastic wave propagation phenomena in two-dimensional periodic beam lattices are studied by using the Bloch wave transform. The numerical modeling is applied to the hexagonal and the rectangular beam lattices, in which, both the in-plane （with respect to the lattice plane） and out-of-plane waves are considered. The dispersion relations are obtained by calculating the Bloch eigenfrequencies and eigenmodes. The frequency bandgaps are observed and the influence of the elastic and geometric properties of the primitive cell on the bandgaps is studied. By analyzing the phase and the group velocities of the Bloch wave modes, the anisotropic behaviors and the dispersive characteristics of the hexagonal beam lattice with respect to the wave prop- agation are highlighted in high frequency domains. One im- portant result presented herein is the comparison between the first Bloch wave modes to the membrane and bend- ing/transverse shear wave modes of the classical equivalent homogenized orthotropic plate model of the hexagonal beam lattice. It is shown that, in low frequency ranges, the homog- enized plate model can correctly represent both the in-plane and out-of-plane dynamic behaviors of the beam lattice, its frequency validity domain can be precisely evaluated thanks to the Bloch modal analysis. As another important and original result, we have highlighted the existence of the retro- propagating Bloch wave modes with a negative group veloc- ity, and of the corresponding ＂retro-propagating＂ frequency bands.

关键词： Elastic wave propagation Periodic beam lattice Bloch wave theory Bandgaps Anisotropy Disper- sion relation

Controllability of a class of conformable fractional differential system

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Journal of Control and Decision 2021年第4期8卷 415-421页

作者： Sanjukta Das ecole centrale School of Engineering Mahindra UniversityHyderabadIndia

The controllability of a class of conformable fractional differential system with a non-densely defined linear part satisfying Hille-Yosida condition,is *** existence of mild solution and controllability is established by Banach-fixed point theorem for the system with non-local conditions and control term appearing also in the nonlinear *** example is discussed to illustrate the results.

关键词： Non-dense operator deviated argument non-local conditions conformable fractional differential equation controllability

Characterization of Particle Emissions of Turbocharged Direct Injection Gasoline Engine in Transients and Hot Start Conditions

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Journal of Thermal Science 2021年第6期30卷 2056-2070页

作者： Vincent BERTHOME David CHALET Jean-François HETET ecole centrale de Nantes LHEEA Lab.(ECN/CNRS)Nantes 44300France

Reducing pollutant emissions,particularly soot particles emitted by internal combustion engines,is a major challenge for car *** this paper,the experimental setup is a turbocharged three-cylinders gasoline direct injection engine installed on a HORIBA dynamic test driven by a HORIBA STARS *** particle-measuring device is a Pegasor Particles Sensor that measures the current carried by previously electrically charged *** hot engine stabilized tests,with lambda parameter lower or equal to one,have very low emission levels,unlike dynamic *** a consequence,the present paper deals with experiments in transient *** diesel engine,cycle tests show that particulate emissions vary *** understand the phenomenon,a simple transient was created and reproduced a hundred times in order to obtain enough data to analyze and compare these different *** transient starts from idle to reach the speed of 2000 r/min and 60 N·m in 5 *** reach this point,it is necessary to stay in full load for about 3 *** maximum deviations of particles reaches 85%with the standard deviationσ=18%.The cylinder pressure sensor shows significant variations at the very beginning of each transient,i.e.,during the first 500 *** kind of result was observed for Worldwide harmonized Light vehicles Test Cycles(WLTC)with a maximum deviations of particles reaching 75%withσ=30%,on Real Drive Emissions Cycle(RDE)with a maximum deviations of particles reaching 45%withσ=22%and for a 300 s Mini-Cycle with a maximum deviations of particles reaching 70%withσ=17%.The Mini-cycle is made up of the five largest accelerations of the WLTP cycle.A complete analysis highlights the importance of filling the first engine *** depends on the opening speed of the throttle,the position of the crankshaft at the beginning of the transient,and the acceleration of the first ***,the NO_(x) sensor shows very slight variations between each *** a consequence,i

关键词： particles gasoline engine cycle-to-cycle variations transients oil consumption

A highly stable explicit scheme for a fourth-order nonlinear diffusion filter

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International Journal of Modeling, Simulation, and Scientific Computing 2020年第4期11卷 121-138页

作者： Mahipal Jetta Department of Mathematics Mahindra Ecole Centrale´Hyderabad 500043India

The standard finite difference scheme(forward difference approximation for time derivative and central difference approximations for spatial derivatives)for fourth-order nonlinear diffusion filter allows very small time-step size to obtain stable *** alternating directional implicit(ADI)splitting scheme such as Douglas method is highly stable but compromises accuracy for a relatively larger time-step *** this paper,we develop 3×3 stencils for the approximation of second-order spatial derivatives based on the finite pointset *** then make use of these stencils for approximating the fourth-order partial differential *** show that the proposed scheme allows relatively bigger time-step size than the standard finite difference scheme,without compromising on the quality of the filtered ***,we demonstrate through numerical simulations that the proposed scheme is more efficient,in obtaining quality filtered image,than an ADI splitting scheme.

关键词： Fourth-order partial differential equation image denoising multiplicative noise finite pointset method finite difference method stability.

Recent understanding on the subgrid-scale modeling of large-eddy simulation in physical space

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Science China(Physics,Mechanics & Astronomy) 2014年第12期57卷 2188-2193页

作者： FANG Le SHAO Liang BERTOGLIO J.-P. Laboratory of Mathematics and Physics Ecole Centrale de P'ekin Beijing University of Aeronautics and Astronautics Laboratoire de M'ecaniques des Fluides et d'Acoustique Ecole Centrale de Lyon

In the last 50 years,the methodology of large-eddy simulation(LES)has been greatly developed,while lots of different subgridscale(SGS)models have ***,the understanding of the procedure of SGS modeling is still not *** present contribution aims at reviewing the recent SGS models and,more importantly,expressing our recent understanding on the SGS modeling of LES in physical *** the Kolmogorov equation for filtered quantities(KEF)as an example,it is argued that the KEF alone is not enough to be a closure *** physical laws are then introduced to complete this closure procedure and are expected to inspire the future researches of SGS modeling.

关键词： large-eddy simulation subgrid-scale modeling Koimogorov equation

Topological Studies of Three-dimensional Flows in a High Pressure Compressor Stator Blade Row without and with Boundary Layer Aspiration

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Chinese Journal of Aeronautics 2011年第5期24卷 541-549页

作者： Ankit SACHDEVA Francis LEBOEUF Laboratoire de Mécanique des Fluides et d'Acoustique Ecole Centrale de Lyon

This paper presents a numerical study of the flow topologies of three-dimensional （3D） flows in a high pressure compressor stator blade row without and with boundary layer aspiration on the hub wall. The stator blade is representative of the first stage operating under transonic inlet conditions and the blade design encourages development of highly complex 3D flows. The blade has a small tip clearance. The computational fluid dynamics （CFD） studies show progressive increase of hub corner stall with the increase in incidence. Aspiration is implemented on the hub wall via a slot in the comer between the hub wall and the suction surface. The CFD studies show aspiration to be sensitive to the suction flow rate; lower rate leads to very complex flow struc- tures and increased level of losses whereas higher rate renders aspiration effective for control of hub comer separation. The flow topologies are studied by trace of skin friction lines on the walls. The nature of flow can be explained by the topological rules of closed separation. Furthermore, a deeper analysis is done for a particular case with advanced criterion to test the non-degeneracy of critical points in the flow field.

关键词： high pressure compressor flow topologies three-dimensional flows boundary layer aspiration tip clearance

Displacement manifold method for type synthesis of lower-mobility parallel mechanisms

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Science China(Technological Sciences) 2004年第6期47卷 641-650页

作者： LI Qinchuan HUANG Zhen Jacques Marie Hervé Center of Integration Engineering Zhejiang University of SciencesHangzhou 310033China Robotics Research Center Yanshan UniversityQinhuangdao 066004China ecole centrale paris France

Type synthesis of lower-mobility parallel mechanisms is a hot and frontier topic in international academic and industrial field. Based on the Lie group theory, a displacement manifold synthesis method is proposed. For all the nine kinds of lower-mobility parallel mechanisms, the mechanism displacement manifold, limb displacement manifold and the geometrical conditions which guarantee that the intersection of the limb displacement manifold is the desired mechanism displacement manifold are enumerated. Various limb kinematic chains can be obtained using the product closure of displacement subgroup. Parallel mechanisms can be constructed with these limbs while obeying the geometrical conditions. Hence, all the nine kinds of lower-mobility parallel mechanisms can be synthesized using this method. Since displacement manifold deals with finite motion, the result mechanism of synthesis have full-cycle mobility. Novel architectures of lower-mobility parallel mechanisms can be obtained using this method.

关键词： lower-mobility parallel mechanisms Lie group displacement manifold type synthesis

Investigation of dynamics of discrete framed structures by a numerical wave-based method and an analytical homogenization approach

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Chinese Journal of Aeronautics 2017年第1期30卷 66-74页

作者： Zhou Changwei Sun Xiangkun Mohamed Ichchou Abdel-Malek Zine Jean-Pierre Lainé Stephane Hans Claude Boutin Laboratory of Tribology and Systems Dynamics Ecole Centrale de Lyon Ecully 69134 France Institut Camille Jordan Ecole Centrale de Lyon Ecully 69134 France Laboratory of Tribology and Systems Dynamics Ecole Nationale des Travaux Publics de l'Etat Vaulx-en-Velinx 69518 France

In this article, the analytical homogenization method of periodic discrete media（HPDM）and the numerical condensed wave finite element method（CWFEM） are employed to study the longitudinal and transverse vibrations of framed structures. The valid frequency range of the HPDM is re-evaluated using the wave propagation feature identified by the CWFEM. The relative error of the wavenumber by the HPDM compared to that by the CWFEM is illustrated in functions of frequency and scale ratio. A parametric study on the thickness of the structure is carried out where the dispersion relation and the relative error are given for three different thicknesses. The dynamics of a finite structure such as natural frequency and forced response are also investigated using the HPDM and the CWFEM.

关键词： Framed structures Homogenization method Periodic structures Wave finite element method Wave propagation