检索结果-南通市图书馆

Reduced Basis Approximation and Error Bounds for Potential Flows in Parametrized geometries

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2011年第1期9卷 1-48页

作者： gianluigi rozza Massachusetts Institute of Technology Department of Mechanical EngineeringRoom 3-26477 Massachusetts AvenueCambridge MA02142-4307USA Modelling and Scientific Computing Ecole Polytechnique Federale de LausanneStation 8-MACH 1015LausanneSwitzerland.

In this paper we consider(hierarchical,Lagrange)reduced basis approximation and a posteriori error estimation for potential flows in affinely parametrized *** review the essential ingredients:i)a galerkin projection onto a lowdimensional space associated with a smooth“parametric manifold”in order to get a dimension reduction;ii)an efficient and effective greedy sampling method for identification of optimal and numerically stable approximations to have a rapid convergence;iii)an a posteriori error estimation procedure:rigorous and sharp bounds for the linearfunctional outputs of interest and over the potential solution or related quantities of interest like velocity and/or pressure;iv)an Offline-Online computational decomposition strategies to achieve a minimum marginal computational cost for high performance in the real-time and many-query(e.g.,design and optimization)*** present three illustrative results for inviscid potential flows in parametrized geometries representing a Venturi channel,a circular bend and an added mass problem.

关键词： Reduced basis approximation error bounds potential flows galerkin method a posteriori error estimation parametrized geometries

Reduced Basis Approaches in Time-Dependent Non-Coercive Settings for Modelling the Movement of Nuclear Reactor Control Rods

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2016年第6期20卷 23-59页

作者： Alberto Sartori Antonio Cammi Lelio Luzzi gianluigi rozza Politecnico di Milano–Department of Energy CeSNEFEnrico Fermi Center for Nuclear Studiesvia La Masa 3420156MilanoItaly SISSA International School for Advanced StudiesMathematics Area–mathLabVia Bonomea 26534136 TriesteItaly.

In this work,two approaches,based on the certified Reduced Basis method,have been developed for simulating the movement of nuclear reactor control rods,in time-dependent non-coercive settings featuring a 3D geometrical *** particular,in a first approach,a piece-wise affine transformation based on subdomains division has been implemented for modelling the movement of one control *** the second approach,a“staircase”strategy has been adopted for simulating themovement of all the three rods featured by the nuclear reactor chosen as case *** neutron kinetics has been modelled according to the so-called multi-group neutron diffusion,which,in the present case,is a set of ten coupled parametrized parabolic equations(two energy groups for the neutron flux,and eight for the precursors).Both the reduced order models,developed according to the two approaches,provided a very good accuracy comparedwith high-fidelity results,assumed as“truth”*** the same time,the computational speed-up in the Online phase,with respect to the fine“truth”finite element discretization,achievable by both the proposed approaches is at least of three orders of magnitude,allowing a real-time simulation of the rod movement and control.

关键词： Reduced basis method control rod movement spatial kinetics parametrized geometry multi-group neutron diffusion non-coercive operators

A Novel Iterative Penalty Method to Enforce Boundary Conditions in FiniteVolume POD-galerkin Reduced Order Models for Fluid Dynamics Problems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2021年第6期30卷 34-66页

作者： S.Kelbij Star giovanni Stabile Francesco Belloni gianluigi rozza Joris Degroote SCK CEN Institute for Advanced Nuclear SystemsBoeretang 2002400MolBelgium ghent University Department of ElectromechanicalSystems and Metal EngineeringSint-Pietersnieuwstraat 41B-9000 GhentBelgium SISSA International School for Advanced StudiesMathematics AreamathLabvia Bonomea 26534136 TriesteItaly

A Finite-Volume based POD-galerkin reduced ordermodel is developed for fluid dynamics problems where the(time-dependent)boundary conditions are controlled using two different boundary control strategies:the lifting function method,whose aim is to obtain homogeneous basis functions for the reduced basis space and the penalty method where the boundary conditions are enforced in the reduced order model using a penalty *** penalty method is improved by using an iterative solver for the determination of the penalty factor rather than tuning the factor with a sensitivity analysis or numerical *** boundary control methods are compared and tested for two cases:the classical lid driven cavity benchmark problem and a Y-junction flow case with two inlet channels and one outlet *** results show that the boundaries of the reduced order model can be controlled with the boundary control methods and the same order of accuracy is achieved for the velocity and pressure ***,the reduced order models are 270-308 times faster than the full ordermodels for the lid driven cavity test case and 13-24 times for the Y-junction test case.

关键词： Proper Orthogonal Decomposition Navier-Stokes equations galerkin projection penalty method lifting function method iterative method

Parametric POD-galerkin Model Order Reduction for Unsteady-State Heat Transfer Problems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2020年第1期27卷 1-32页

作者： Sokratia georgaka giovanni Stabile gianluigi rozza Michael J.Bluck Imperial College London Department of Mechanical EngineeringLondonSW72BXUK SISSA International School for Advanced StudiesMathematics AreamathLabvia Bonomea 265–34136TriesteItaly

A parametric reduced order model based on proper orthogonal decomposition with galerkin projection has been developed and applied for the modeling of heat transport in T-junction pipes which are widely found in nuclear power reactor cooling *** mixing of different temperature coolants in T-junction pipes leads to temperature fluctuations and this could potentially cause thermal fatigue in the pipe *** novelty of this paper is the development of a parametric ROM consider-ing the three dimensional,incompressible,unsteady Navier-Stokes equations coupled with the heat transport equation in a finite volume *** different parametric cases are presented in this paper:parametrization of the inlet temperatures and parametrization of the kinematic *** training spaces are considered and the results are compared against the full order *** first test case results to a computational speed-up factor of 374 while the second test case to one of 211.

关键词： Proper orthogonal decomposition finite volume approximation Poisson equation for pressure inf-sup approximation supremizer velocity space enrichment Navier-Stokes equations

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

X染色体变异在高血压家族遗传中的可能作用

中华高血压杂志 2016年第4期24卷 316-316页

作者：刘莉叶鹏 Ciccarelli M Finelli R Rivera N Santulli g Izzo R De Luca N rozza F Ceccarelli M5 Pagnotta S Uliano F Tremigliozzi R Condorelli g Trimarco V Iaccarino g

最近的全基因组研究结果表明,人类基因组某些区域可能参与高血压表型的传递,高血压家族遗传参与高血压的发病。但以往研究主要涉及常染色体,迄今为止,对于性染色体在高血压家族遗传中的作用还未阐明。研究人员获取意大利那不勒斯费德里... 详细信息

最近的全基因组研究结果表明,人类基因组某些区域可能参与高血压表型的传递,高血压家族遗传参与高血压的发病。但以往研究主要涉及常染色体,迄今为止,对于性染色体在高血压家族遗传中的作用还未阐明。研究人员获取意大利那不勒斯费德里克二世大学医院高血压中心Campania Salute数据库资料,应用父系、母系遗传及性别（男、女）的二元变量对高血压患者12 504（男6868、女5636）例和对照组人群6352（男3484、女2868）名进行分析。

关键词： X染色体家族遗传数据库资料母系遗传人类基因组常染色体大学医院染色体变异基因组研究德里克

在动脉性高血压患者中,是否心脏收缩和舒张功能信息有助于预测由左心室肥大而造成的心血管事件?

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

中华高血压杂志 2010年第10期18卷 969-969页

作者：张玲玉叶鹏 de Simone g Izzo R Chinali M De Marco M Casalnuovo g.rozza F girfoglio D Iovino gL Trimarco B De Lu-ca N

左心室质量（left ventricular mass，LVM）是高血压患者超声心电图检查中最重要的指标。但独立于LVM，左心室功能也能够预测心血管风险。目前没有证据表明，与单纯的LVM相比，左心室功能联合LVM能够显著提高对心血管风险的预测价值。... 详细信息

左心室质量（left ventricular mass，LVM）是高血压患者超声心电图检查中最重要的指标。但独立于LVM，左心室功能也能够预测心血管风险。目前没有证据表明，与单纯的LVM相比，左心室功能联合LVM能够显著提高对心血管风险的预测价值。因此，在无常见心血管疾病的高血压门诊病人5380例（女性2336例，糖尿病298例，肥胖者1315例）中，

关键词：高血压患者预测价值心血管事件左心室肥大功能信息心脏收缩动脉性心血管风险