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Effect of Serial PMSs on Operational Benefits of Arrival Flights
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作者 XU Can WANG Xunuo +1 位作者 TIAN Yong WANG Zhan 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2022年第S01期73-81,共9页
In order to alleviate the flight congestion in terminal areas(TMAs),it is of great significance to develop an effective method.An arrival sequencing model based on the serial point merge systems(PMSs)is constructed to... In order to alleviate the flight congestion in terminal areas(TMAs),it is of great significance to develop an effective method.An arrival sequencing model based on the serial point merge systems(PMSs)is constructed to improve the operational benefits of arrival flights.The approach of first come first service(FCFS)combined with the method of constraint position shift(CPS)is used as the sequencing strategy.Through the simulated annealing algorithm,the results show that the arrival flights sequencing through serial PMSs has significant advantages in reducing delays and increasing runway throughput especially in the case of high traffic loads.The proposed approach is conducive in promoting the implementation and application of serial PMS. 展开更多
关键词 serial point merge systems(PMSs) terminal area(TMA) arrival flights operational benefits
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Laboratory investigation of axisymmetric single vacuum well point
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作者 武文俊 姚磊华 魏英杰 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第3期750-756,共7页
Vacuum well point is a new but faint soft ground treatment method. This work focuses on the consolidation behavior of a reconstituted soft clayey specimen under vacuum well point combined with surcharge loading. The l... Vacuum well point is a new but faint soft ground treatment method. This work focuses on the consolidation behavior of a reconstituted soft clayey specimen under vacuum well point combined with surcharge loading. The laboratory test was conducted through a vacuum-surcharge consolidation apparatus, and the vacuum loading scheme was adopted for vacuum pressure application to investigate the vacuum effect on soil consolidation. In the testing process, some key parameters such as vacuum pressure, pore water pressure and settlement deformation were timely recorded. Furthermore, the water content, void ratio and permeability coefficient of samples collected after loading were measured to reflect the consolidation characteristics. By comparing with the membrane system and membraneless system, something different was found for the vacuum well point method. The results indicate that the consolidation behavior of an axisymmetric single vacuum well point is almost identical to the behavior of vacuum preloading combined with prefabricated vertical drain(PVD), except for the distribution of the vacuum pressure along the well drain due to the structure of the vacuum well point. And the vacuum well point method may be useful for the improvement of soft clayey deposit in a certain depth. 展开更多
关键词 soft ground vacuum consolidation vacuum well point systems vacuum pressure
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Multi-recurrence and van der Waerden systems 被引量:1
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作者 KWIETNIAK Dominik LI Jian +1 位作者 OPROCHA Piotr YE XiangDong 《Science China Mathematics》 SCIE CSCD 2017年第1期59-82,共24页
We explore recurrence properties arising from dynamical approach to the van der Waerden theorem and similar combinatorial problems. We describe relations between these properties and study their consequences for dynam... We explore recurrence properties arising from dynamical approach to the van der Waerden theorem and similar combinatorial problems. We describe relations between these properties and study their consequences for dynamics. In particular, we present a measure-theoretical analog of a result of Glasner on multi-transitivity of topologically weakly mixing minimal maps. We also obtain a dynamical proof of the existence of a C-set with zero Banach density. 展开更多
关键词 multi-recurrent points van der Waerden systems multiple recurrence theorem multiple IP-recurrence property multi-non-wandering points
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PRECONDITIONING THE INCOMPRESSIBLE NAVIER-STOKES EQUATIONS WITH VARIABLE VISCOSITY 被引量:1
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作者 Xin He Maya Neytcheva 《Journal of Computational Mathematics》 SCIE CSCD 2012年第5期461-482,共22页
This paper deals with preconditioners for the iterative solution of the discrete Oseen problem with variable viscosity. The motivation of this work originates from numerical simulations of multiphase flow, governed by... This paper deals with preconditioners for the iterative solution of the discrete Oseen problem with variable viscosity. The motivation of this work originates from numerical simulations of multiphase flow, governed by the coupled Cahn-Hilliard and incompressible Navier-Stokes equations. The impact of variable viscosity on some known precondition- ing technique is analyzed. Theoretical considerations and numerical experiments show that some broadly used preconditioning techniques for the Oseen problem with constant viscosity are also efficient when the viscosity is vaxving. 展开更多
关键词 Navier-Stokes equations Saddle point systems Augmented Lagrangian FINITEELEMENTS Iterative methods Preconditioning.
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Numerical Studies of Vanka-Type Smoothers in Computational Solid Mechanics
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作者 Hilmar Wobker Stefan Turek 《Advances in Applied Mathematics and Mechanics》 SCIE 2009年第1期29-55,共27页
In this paper multigrid smoothers of Vanka-type are studied in the context of Computational Solid Mechanics(CSM).These smoothers were originally developed to solve saddle-point systems arising in the field of Comput... In this paper multigrid smoothers of Vanka-type are studied in the context of Computational Solid Mechanics(CSM).These smoothers were originally developed to solve saddle-point systems arising in the field of Computational Fluid Dynamics(CFD),particularly for incompressible flow problems.When treating(nearly)incompressible solids,similar equation systems arise so that it is reasonable to adopt the‘Vanka idea’for CSM.While there exist numerous studies about Vanka smoothers in the CFD literature,only few publications describe applications to solid mechanical problems.With this paper we want to contribute to close this gap.We depict and compare four different Vanka-like smoothers,two of them are oriented towards the stabilised equal-order Q_(1)/Q_(1)finite element pair.By means of different test configurations we assess how far the smoothers are able to handle the numerical difficulties that arise for nearly incompressible material and anisotropic meshes.On the one hand,we show that the efficiency of all Vanka-smoothers heavily depends on the proper parameter choice.On the other hand,we demonstrate that only some of them are able to robustly deal with more critical situations.Furthermore,we illustrate how the enclosure of the multigrid scheme by an outer Krylov space method influences the overall solver performance,and we extend all our examinations to the nonlinear finite deformation case. 展开更多
关键词 Coupled multigrid Vanka smoother linear and finite elasticity nearly incompressible material saddle point systems finite elements
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