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Simulation of Wave Impact on a Horizontal Deck Based on SPH Method 被引量:3
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作者 孙家文 梁书秀 +1 位作者 孙昭晨 赵西增 《Journal of Marine Science and Application》 2010年第4期372-378,共7页
A numerical model was established for simulating wave impact on a horizontal deck by an improved incompressible smoothed particle hydrodynamics (ISPH). As a grid-less particle method, the ISPH method has been widely u... A numerical model was established for simulating wave impact on a horizontal deck by an improved incompressible smoothed particle hydrodynamics (ISPH). As a grid-less particle method, the ISPH method has been widely used in the free-surface hydrodynamic flows with good accuracy. The improvement includes the employment of a corrective function for enhancement of angular momentum conservation in a particle-based calculation and a new estimation method to predict the pressure on the horizontal deck. The simulation results show a good agreement with the experiment. The present numerical model can be used to study wave impact load on the horizontal deck. 展开更多
关键词 incompressible smoothed particle hydrodynamics (ISPH) wave impact kernel gradient correction
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An Improved Parameter Dimensionality Reduction Approach Based on a Fast Marching Method for Automatic History Matching
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作者 Hairong Zhang Yongde Gao +4 位作者 Wei Li Deng Liu Jing Cao Luoyi Huang Xun Zhong 《Fluid Dynamics & Materials Processing》 EI 2022年第3期609-628,共20页
History matching is a critical step in reservoir numerical simulation algorithms.It is typically hindered by difficulties associated with the high-dimensionality of the problem and the gradient calculation approach.He... History matching is a critical step in reservoir numerical simulation algorithms.It is typically hindered by difficulties associated with the high-dimensionality of the problem and the gradient calculation approach.Here,a multi-step solving method is proposed by which,first,a Fast marching method(FMM)is used to calculate the pressure propagation time and determine the single-well sensitive area.Second,a mathematical model for history matching is implemented using a Bayesian framework.Third,an effective decomposition strategy is adopted for parameter dimensionality reduction.Finally,a localization matrix is constructed based on the single-well sensitive area data to modify the gradient of the objective function.This method has been verified through a water drive conceptual example and a real field case.The results have shown that the proposed method can generate more accurate gradient information and predictions compared to the traditional analytical gradient methods and other gradient-free algorithms. 展开更多
关键词 History matching parameter dimensionality reduction sensitive area gradient correction
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Compton profiles of NiO and TiO_2 obtained from first principles GWA spectral function
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作者 S M Khidzir M F M Halid W A T Wan Abdullah 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第6期407-415,共9页
In this work,we first use momentum density studies to understand strongly correlated electron behavior,which is typically seen in transition metal oxides.We observe that correlated electron behavior as seen in bulk Ni... In this work,we first use momentum density studies to understand strongly correlated electron behavior,which is typically seen in transition metal oxides.We observe that correlated electron behavior as seen in bulk NiO is due to the Fermi break located in the middle of overlapping spectral functions obtained from a GW(G is Green’s function and W is the screened Coulomb interaction) approximation(GWA) calculation while in the case of TiO2 we can see that the origin of the constant momentum distribution in lower momenta is due to a pile up of spectra before the Fermi energy.These observations are then used to compare our calculated Compton profiles with previous experimental studies of Fukamachi and Limandri.Our calculations for NiO are observed to follow the same trend as the experimental profile but it is seen to have a wide difference in the case of TiO2 before the Fermi break.The ground state momentum densities differ significantly from the quasiparticle momentum density,thus stressing the importance of the quasiparticle wave function as the input for the study of charge density and the electron localization function.Finally we perform a calculation of the quasiparticle renormalization function,giving a quantitative description of the discontinuity of the GWA momentum density. 展开更多
关键词 elastic and Compton scattering density functional theory local density approximation gradient and other corrections elements OXIDES nitrides borides carbides CHALCOGENIDES
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Corrective Plate With a Gradient Index Media in the Catadioptiric System
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作者 Qiao Yatian (Xian Institute of Posts and Telecommunications,Xian 710061, P. R. China) 《The Journal of China Universities of Posts and Telecommunications》 EI CSCD 1994年第1期57-59,共3页
In this paper a gradient index media plate is described. The media plate has some properties similar to the Schmidt aspherical corrective plate. In the catadioptiric system,Duncan T. Moors has studied a axial gradien... In this paper a gradient index media plate is described. The media plate has some properties similar to the Schmidt aspherical corrective plate. In the catadioptiric system,Duncan T. Moors has studied a axial gradient index corrective plate and gave a better result. His plate,in fact,is a zero power plate with two Spherical surfaces of different radius of curvature. However ,my plate is a parallel plate designed forth a shallow radial gradient index media. The spherical aberration of the gradient index corrector with parallel plane ed eliminate the spherical aberration of the spherical primary mirror in the catadioptiric system. In this paper the aberrational correction is analyzed. In the conventional optical systems,this gradient index plate is used to provide the precorrectional quantity of the spherical aberration of the optical lee systems. The refractive index in such a media in the lens systems is given in the same way. 展开更多
关键词 gradient index optics Corrective plate with gradient index media
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