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3-D SHALLOW WATER FLOW COMPUTATION BY A SEMIIMPLICIT FINITE ELEMENT METHOD

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Journal of Hydrodynamics 1998年第2期10卷 21-28页

作者： jin, sheng Dalian Univ of Technology Dalian China

A simi-implicit finite element method is developed for three-dimensional shallow water flow. By using water depth to scale the vertical coordinate. the governing equation is transformed into fixed computational domain... 详细信息

关键词： 3-D flow shallow water iterative scheme finite element

Hausdorff Dimensions of Quasilines and Differentiability of Quasisymmetric Homeomorphisms

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Acta Mathematica Sinica,English Series 2016年第4期32卷 499-506页

作者： sheng jin HUO sheng Jian WU Department of Mathematics Tianjin Polytechnic University LMAM and School of Mathematical Sciences Peking University

In this paper,we try to describe the relationship between the differentiability of a quasisymmetric homeomorphism and the local Hausdorff dimension of the quasiline at a point.

关键词： Quasiline quasisymmetric Fuchsian group Mostow’s rigidity

APPLICATION OF VIDEO ANAGLYPH MAKER FOR 3-D FLOW SIMULATION

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Journal of Hydrodynamics 2010年第2期22卷 289-294页

作者： KANG Su-hai jin sheng State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024China Key Laboratory of Engineering Sediment of Ministry of Communications Tianjin Research Institute for WaterTransport Engineering Tianjin 300456 China

In this article,the anaglyph video maker is employed for generating realistic 3-D flows and the software FlowAnimator is developed using that *** on Microsoft Windows Presentation Foundation（WPF）,the real 3-D scene is set up and marker particles are distributed in it randomly in order to create a more natural flow *** trajectory of the particle motion is calculated with Lagrangian description in 3-D *** the simulation,the viewport can be changed in order to focus on different parts of the model by panning,zooming,rotating and inclination variation *** particles may appear in different shapes：spheres,tracking-balls,cylinders and ribbons in order to fit different *** is the first time that the video anaglyph technology is employed in the 3-D hydrodynamic simulation,which removes the obstacles for 3-D scenes to be rendered on a flat-panel display.

关键词： 3-D simulation flow simulation anaglyph stereoscopy Windows Presentation Foundation(WPF)

A Note on the Density of a Subset of All Integrable Holomorphic Quadratic Differentials

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Acta Mathematica Sinica,English Series 2014年第5期30卷 793-796页

作者： sheng jin HUO Department of Mathematics Tianjin Polytechnic University

Let T0（Δ） be the subset of the universal Teichm¨uller space, which consists all of the elements with boundary dilatation 1. Let SQ（Δ） be the unit ball of the space Q（Δ） of all integrable holomorphic quadratic differentials on the unit disk Δ and Q0（Δ） be defined as Q0（Δ） = {？ ∈ SQ（Δ）： there exists a k ∈（0, 1） such that [kˉ？｜？｜] ∈ T0（Δ）}. In this paper, we show that Q0（Δ） is dense in SQ（Δ）.

关键词： Teichm¨uller space quadratic differential Hamilton sequence

The internal structure models of Europa

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Science China(Physics,Mechanics & Astronomy) 2012年第1期55卷 156-161页

作者： jin sheng JI JiangHui Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210008 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

We model the interior of Europa using a method by which we set three layers of Europa and the composition of each layer in advance. Comparing the calculated mass and radius related to each model with the data derived by the observations, we propose three possible internal structure models for Europa. All models are assumed to be differentiated into a metallic core, a (Mg,Fe)2SiO4 silicate mantle and an outer water shell. The only difference amongst these models are the composition of the core. The core of Model I is composed of Fe, while Model II composed of FeS, and the two models are based on the inferences provided by Europa's external gravitational field. Model III has a core which consists of Fe-FeS alloy, similar to that of Earth's outer core. Model I has a Fe core with a radius of 431 km, a (Mg,Fe)2SiO4 mantle with 999 km and a water shell with 132 km. Model II has a 777 km FeS core, a 619 km (Mg,Fe)2SiO4 mantle and a 167 km water shell. Model III has a 571 km Fe0.8(FeS)0.2 core, a 832 km (Mg,Fe)2SiO4 mantle and a 166 km water shell. In all three models, the density range and the radius of each layer is consistent with those deduced by Anderson et al.

关键词： Europa internal structure equation of state

Investigation of vortical flow over bluff bodies with base cavities

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Acta Mechanica Sinica 2012年第5期28卷 1238-1247页

作者： Shu-Cheng Pan jin-sheng Cai National Key Laboratory of Aerodynamic Design and Research Northwestern Polytechnical University

Based on our previous research about drag reduction in term of the base cavity length using two dimensional simulations, this paper describes a numerical study of a bluff body of which the number of base cavities is successively increased and the cavity geometries are also modified to assume different shapes. Here we attempt to find an effective configuration to reduce the drag by increasing the number of base cavities. The numerical simulations examining varied number of base cavities reveal the presence of different strength of vortices in the wake zone which is the reason why the drag coefficients are distinctly different for different cases. In the case with double and triple rectangular cavities, we use the pressure contours snapshots at successive time instants to describe the wake evolution. We further investigate the effect of variable base cavity shapes for a constant cavity length at an identical time instant. A total of two different geometries of base cavities are discussed here： the rectangular and the sinusoidal cavities with sharp and rounded trailing edges, respectively. The numerical results reveal that the for- mer is an effective drag reduction configuration which can produce a significant base pressure recovery corresponding to the strength of the vortices shown in the pressure contour figures. While the latter shows no obvious reduction in drag coefficient and a similar intensity of vortex in the wake zone compared with the unmodified case. Reductions in drag are observed for all the investigated cavity configurations, and additionally it is found that the magnitude of the reduction bears a direct relationship with the number of the cavities up to a certain minimum value.

关键词： Flow control Drag reduction. Bluff body Basecavity

3-D numerical simulation of curved open channel confluence flow with partially non-submerged rigid vegetation

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Journal of Hydrodynamics 2021年第5期33卷 992-1006页

作者： Zheng-rui Shi Cong-fang Ai sheng jin School of Civil and Hydraulic Engineering Dalian University of TechnologyDalian 116024China

For the study of the effects of partially non-submerged rigid vegetation on the free-surface confluence flow in a curved open channel,a numerical simulation is carried out by using the Volume of Fluid model combined with the porous media model with the software *** model is first validated by using available experimental measurement data with a good ***,the characteristics of the separation zone generated by the centrifugal forces and the confluence flow are *** to the resistance created by the vegetation,the velocities in the separation zone are more chaotic and the separation zone becomes smaller and more *** reduction of the separation zone area of the vegetated flow in the convex bank is more significant than that in the concave *** velocities in the vegetated region become much smaller and remains so in the downstream flow after the vegetation ***,the vegetation compresses and divides the circulations in the flow area,rebuilding a structure with smaller circulations in the main flow and unclear circulations in the vegetation *** addition,the bed wall shear stresses are significantly smaller in the vegetation region and the separation zone compared to the non-vegetated *** implies that the vegetation can have the effect of protecting the river bed from erosion.

关键词： Curved open channel confluence flow porous media model non-submerged rigid vegetation separation zone

FVS SCHEME FOR SEVERE TRANSIENT FLOW IN PIPE NETWORKS

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Journal of Hydrodynamics 2005年第5期17卷 621-628页

作者： GENG Yan-fen WANG Zhi-li jin sheng State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian116024 China Nanjing Hydraulic Research Institute Nanjing 210024 China State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China

An efficient numerical method with first and second order accuracy is developed by the flux split technology to simulate the water hammer problem in single and multiple pipe networks under severe transient conditions. The finite volume formulation ensures that both schemes conserve mass and momentum and produces physically realizable shock fronts. The conception of the fictitious cell at the junction is developed. The typical water hammer problem and the experi ment with friction and the comprehensive orbicular network with control valve and pressure relief valve and surge tank are implemented to test the numerical method. Strong numerical evidences show that the proposed scheme has several desirable properties, such as, accurate, efficient, robust, high shock resolution, conservative and stable for Courant number.

关键词： pipe networks water hammer flux vector splitting fictitious cell finite volume method

A STUDY ON UNSTEADY SEEPAGE FLOW THROUGH DAM

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Journal of Hydrodynamics 2009年第4期21卷 499-504页

作者： FU Jun-feng jin sheng State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China

A numerical model is proposed to simulate the unsteady seepage flow through dam, with both saturation and water head as variables to describe the seepage domain. Experiments of seepage flow through dam with unsteady conditions were conducted in laboratory to verify the reliability and the accuracy of the numerical model. The performance of the model is also assessed by comparing with analytical solutions. The examples show that the accuracy and the reliability of the model are adequate to handle seepage flow problems with complex conditions. It is also demonstrated that the method of determining the seepage surface through the saturation description is natural, logical and practical in actual applications. The method provides a relatively simple computing scheme, as compared with traditional methods.

关键词： saturation unsteady seepage saturated and unsaturated seepage finite element method