水动力学研究与进展:英文版最新文献_第4页

On the clean numerical simulation (CNS) of chaotic dynamic systems 混沌动力系统的洁净数值模拟(CNS)

3区工程技术

水动力学研究与进展:英文版 Pub Date : 2017-10-01 DOI: 10.1016/S1001-6058(16)60785-0

Shi-jun Liao (（廖世俊）)

{"title":"On the clean numerical simulation (CNS) of chaotic dynamic systems","authors":"Shi-jun Liao (（廖世俊）)","doi":"10.1016/S1001-6058(16)60785-0","DOIUrl":"10.1016/S1001-6058(16)60785-0","url":null,"abstract":"<div><p>According to Lorenz, chaotic dynamic systems have sensitive dependence on initial conditions (SDIC), i.e., the butterfly-effect: a tiny difference on initial conditions might lead to huge difference of computer-generated simulations after a long time. Thus, computer-generated chaotic results given by traditional algorithms in double precision are a kind of mixture of “true” (convergent) solution and numerical noises at the same level. Today, this defect can be overcome by means of the “clean numerical simulation” (CNS) with negligible numerical noises in a long enough interval of time. The CNS is based on the Taylor series method at high enough order and data in the multiple precision with large enough number of digits, plus a convergence check using an additional simulation with even smaller numerical noises. In theory, convergent (reliable) chaotic solutions can be obtained in an arbitrary long (but finite) interval of time by means of the CNS. The CNS can reduce numerical noises to such a level even much smaller than micro-level uncertainty of physical quantities that propagation of these physical micro-level uncertainties can be precisely investigated. In this paper, we briefly introduce the basic ideas of the CNS, and its applications in long-term reliable simulations of Lorenz equation, three-body problem and Rayleigh-Bénard turbulent flows. Using the CNS, it is found that a chaotic three-body system with symmetry might disrupt without any external disturbance, say, its symmetry-breaking and system-disruption are “self-excited”, i.e., out-of-nothing. In addition, by means of the CNS, we can provide a rigorous theoretical evidence that the micro-level thermal fluctuation is the origin of macroscopic randomness of turbulent flows. Naturally, much more precise than traditional algorithms in double precision, the CNS can provide us a new way to more accurately investigate chaotic dynamic systems.</p></div>","PeriodicalId":66131,"journal":{"name":"水动力学研究与进展:英文版","volume":"29 5","pages":"Pages 729-747"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1001-6058(16)60785-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4054919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 17

Simulation of flows with moving contact lines on a dual-resolution Cartesian grid using a diffuse-interface immersed-boundary method 用扩散界面浸没边界法模拟双分辨率笛卡尔网格上的运动接触线流动

3区工程技术

水动力学研究与进展:英文版 Pub Date : 2017-10-01 DOI: 10.1016/S1001-6058(16)60788-6

Hao-ran Liu (刘浩然), Han Li (李晗), Hang Ding (丁航)

{"title":"Simulation of flows with moving contact lines on a dual-resolution Cartesian grid using a diffuse-interface immersed-boundary method","authors":"Hao-ran Liu (刘浩然), Han Li (李晗), Hang Ding (丁航)","doi":"10.1016/S1001-6058(16)60788-6","DOIUrl":"10.1016/S1001-6058(16)60788-6","url":null,"abstract":"<div><p>In this paper, we investigate flows with moving contact lines on curved solid walls on a dual-resolution grid using a diffuse-interface immersed-boundary (DIIB) method. The dual-resolution grid, on which the flows are solved on a coarse mesh while the interface is resolved on a fine mesh, was shown to significantly improve the computational efficiency when simulating multiphase flows. On the other hand, the DIIB method is able to resolve dynamic wetting on curved substrates on a Cartesian grid, but it usually requires a mesh of high resolution in the vicinity of a moving contact line to resolve the local flow. In the present study, we couple the DIIB method with the dual-resolution grid, to improve the interface resolution for flows with moving contact lines on curved solid walls at an affordable cost. The dynamic behavior of moving contact lines is validated by studying drop spreading, and the numerical results suggest that the effective slip length λ<sub><em>n</em></sub> can be approximated by 1.9<em>Cn</em>, where <em>Cn</em> is a dimensionless measure of the thickness of the diffuse interface. We also apply the method to drop impact onto a convex substrate, and the results on the dual-resolution grid are in good agreement with those on a single-resolution grid. It shows that the axisymmetric simulations using the DIIB method on the dual-resolution grid saves nearly 60% of the computational time compared with that on a single-resolution grid.</p></div>","PeriodicalId":66131,"journal":{"name":"水动力学研究与进展:英文版","volume":"29 5","pages":"Pages 774-781"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1001-6058(16)60788-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4055644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Numerical simulation of three-dimensional breaking waves and its interaction with a vertical circular cylinder 三维破碎波及其与垂直圆柱相互作用的数值模拟

3区工程技术

水动力学研究与进展:英文版 Pub Date : 2017-10-01 DOI: 10.1016/S1001-6058(16)60791-6

Zhihua Xie , Lin Lu (吕林) , Thorsten Stoesser , Jian-guo Lin (林建国) , Dimitrios Pavlidis , Pablo Salinas , Christopher C. Pain , Omar K. Matar

引用次数: 11

Flow structure and phosphorus adsorption in bed sediment at a 90° channel confluence 90°河道合流河床沉积物的流动结构与磷吸附

3区工程技术

水动力学研究与进展:英文版 Pub Date : 2017-10-01 DOI: 10.1016/S1001-6058(16)60804-1

Yang Xiao (肖洋) , Yang Xia (夏阳) , Sai-yu Yuan (袁赛瑜) , Hong-wu Tang (唐洪武)

{"title":"Flow structure and phosphorus adsorption in bed sediment at a 90° channel confluence","authors":"Yang Xiao (肖洋) , Yang Xia (夏阳) , Sai-yu Yuan (袁赛瑜) , Hong-wu Tang (唐洪武)","doi":"10.1016/S1001-6058(16)60804-1","DOIUrl":"10.1016/S1001-6058(16)60804-1","url":null,"abstract":"<div><p>The distribution of the phosphorus (P) adsorption in a bed sediment at channel confluences is an important issue for understanding the transport of contaminants in channel networks. In this study, the flow structure and its effect on the P distribution in the bed sediment were investigated in a 90° confluence flume. It is shown that the P adsorption amount in the sediment varies significantly in different hydrodynamic zones. The P adsorption amount is high in the flow separation zone where the horizontal velocity of the flow is very small, and it is low in the maximum velocity zone where the flow velocity reaches a maximum. The low P adsorption amount is observed in the downstream portion of the distorted shear layer, while the P enrichment is found in the upstream portion, as is related to the significant downwelling flow in this zone. Thus, the flow structure, especially, the flow velocity, has a significant effect on the distribution of the P adsorption in the bed sediment at the channel confluences.</p></div>","PeriodicalId":66131,"journal":{"name":"水动力学研究与进展:英文版","volume":"29 5","pages":"Pages 902-905"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1001-6058(16)60804-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4055658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 9

Mechanism of air-trapped vertical vortices in long-corridor-shaped surge tank of hydropower station and their elimination 水电站长廊道式调压池内空气困住垂直涡的形成机理及消除

3区工程技术

水动力学研究与进展:英文版 Pub Date : 2017-10-01 DOI: 10.1016/S1001-6058(16)60796-5

Fang Cai (蔡芳) , Yong-guang Cheng (程永光) , Lin-sheng Xia (夏林生) , Yong-qi Jiang (蒋永琪)

{"title":"Mechanism of air-trapped vertical vortices in long-corridor-shaped surge tank of hydropower station and their elimination","authors":"Fang Cai (蔡芳) , Yong-guang Cheng (程永光) , Lin-sheng Xia (夏林生) , Yong-qi Jiang (蒋永琪)","doi":"10.1016/S1001-6058(16)60796-5","DOIUrl":"10.1016/S1001-6058(16)60796-5","url":null,"abstract":"<div><p>The air-trapped vertical vortices (ATVVs) are easy to form above the throttled orifices in the widely used long-corridor-shaped surge tanks (LCSSTs), when the tank water level decreases rapidly during hydraulic transients. These ATVVs may jeopardize the operation safety of the hydropower stations and should be avoided. This study elucidates the formation mechanism of the ATVVs and proposes some simple measures to eliminate them. The 3-D CFD model for predicting the ATVVs is validated first by physical model tests in a model tailrace LCSST, and then the formation mechanism is analyzed based on the numerical results. It is shown that the main influence factor for the ATVVs is the critical submergence, which can be reduced by minimizing the velocity circulation around the throttled orifices. Two practical ATVV elimination measures through suppressing the velocity circulation are compared and verified, and the optimized one is recommended.</p></div>","PeriodicalId":66131,"journal":{"name":"水动力学研究与进展:英文版","volume":"29 5","pages":"Pages 845-853"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1001-6058(16)60796-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4056232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

On the hydrodynamics of hydraulic machinery and flow control 液压机械流体力学与流动控制

3区工程技术

水动力学研究与进展:英文版 Pub Date : 2017-10-01 DOI: 10.1016/S1001-6058(16)60789-8

Hong-xun Chen (陈红勋) , Zheng Ma (马峥) , Wei Zhang (张伟) , Bing Zhu (朱兵) , Rui Zhang (张睿) , Qun Wei (魏群) , Zheng-chuan Zhang (张正川) , Chao Liu (刘超) , Jian-wu He (何建武)

{"title":"On the hydrodynamics of hydraulic machinery and flow control","authors":"Hong-xun Chen (陈红勋) , Zheng Ma (马峥) , Wei Zhang (张伟) , Bing Zhu (朱兵) , Rui Zhang (张睿) , Qun Wei (魏群) , Zheng-chuan Zhang (张正川) , Chao Liu (刘超) , Jian-wu He (何建武)","doi":"10.1016/S1001-6058(16)60789-8","DOIUrl":"10.1016/S1001-6058(16)60789-8","url":null,"abstract":"<div><p>Hydraulic machinery mainly includes turbine and pump, which is closely related to national economy and people's livelihood involving aerospace industry, marine engineering, hydropower engineering, petroleum industry, chemical industry, mining industry, biomedical engineering, environmental engineering, agricultural water-soil engineering, etc.. The internal flow of hydraulic machinery is extremely complex, and its characteristics can be summarized as high Reynolds number, multi-scales, inhomogeneous and vortex-dominant unsteady turbulence which interact with the rotating dynamic boundary (rotor blade). Based on the analysis of the internal flow characteristics of hydraulic machinery, the author and his research team successively proposed a rotation correction model, a curvature corrected filter-based model, a scalable detached eddy simulation method, and a non-linear hybrid RANS/LES turbulence model to capture unsteady flow structures and then predict hydraulic performance and dynamic characteristics more accurately. According to the analysis on the internal flow, the corresponding flow control measures were put forward. It was verified by experiments that these methods could significantly improve the hydraulic performance, anti-cavitation performance and dynamic characteristics (pressure pulsation and vibration) of hydraulic machinery in a certain range of operating conditions. In addition, the mechanism how flow control measures influence internal flow was analyzed in depth, aiming at finding a feasible and effective way to improve hydraulic performance, anti-cavitation performance and dynamic characteristics of hydraulic machinery.</p></div>","PeriodicalId":66131,"journal":{"name":"水动力学研究与进展:英文版","volume":"29 5","pages":"Pages 782-789"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1001-6058(16)60789-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4056449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 13

A 3-D SPH model for simulating water flooding of a damaged floating structure 一种用于模拟受损浮式结构水淹的三维SPH模型

3区工程技术

水动力学研究与进展:英文版 Pub Date : 2017-10-01 DOI: 10.1016/S1001-6058(16)60795-3

Kai Guo (郭凯) , Peng-nan Sun (孙鹏楠) , Xue-yan Cao (曹雪雁) , Xiao Huang (黄潇)

{"title":"A 3-D SPH model for simulating water flooding of a damaged floating structure","authors":"Kai Guo (郭凯) , Peng-nan Sun (孙鹏楠) , Xue-yan Cao (曹雪雁) , Xiao Huang (黄潇)","doi":"10.1016/S1001-6058(16)60795-3","DOIUrl":"10.1016/S1001-6058(16)60795-3","url":null,"abstract":"<div><p>With the quasi-static analysis method, the terminal floating state of a damaged ship is usually evaluated for the risk assessment. But this is not enough since the ship has the possibility to lose its stability during the transient flooding process. Therefore, an enhanced smoothed particle hydrodynamics (SPH) model is applied in this paper to investigate the response of a simplified cabin model under the condition of the transient water flooding. The enhanced SPH model is presented firstly including the governing equations, the diffusive terms, the boundary implementations and then an algorithm regarding the coupling motions of six degrees of freedom (6-DOF) between the structure and the fluid is described. In the numerical results, a non-damaged cabin floating under the rest condition is simulated. It is shown that a stable floating state can be reached and maintained by using the present SPH scheme. After that, three-dimensional (3-D) test cases of the damaged cabin with a hole at different locations are simulated. A series of model tests are also carried out for the validation. Fairly good agreements are achieved between the numerical results and the experimental data. Relevant conclusions are drawn with respect to the mechanism of the responses of the damaged cabin model under water flooding conditions.</p></div>","PeriodicalId":66131,"journal":{"name":"水动力学研究与进展:英文版","volume":"29 5","pages":"Pages 831-844"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1001-6058(16)60795-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4053961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 22

An ISPH model for flow-like landslides and interaction with structures 流状滑坡及其与结构相互作用的ISPH模型

3区工程技术

水动力学研究与进展:英文版 Pub Date : 2017-10-01 DOI: 10.1016/S1001-6058(16)60802-8

Dongfang Liang (梁东方) , Xuzhen He , Jing-xin Zhang (张景新)

引用次数: 5

Determination of urban runoff coefficient using time series inverse modeling 利用时间序列反演模型确定城市径流系数

3区工程技术

水动力学研究与进展:英文版 Pub Date : 2017-10-01 DOI: 10.1016/S1001-6058(16)60803-X

Hai-long Yin (尹海龙) , Zhi-chao Zhao (赵志超) , Ruoqian Wang , Zu-xin Xu (徐祖信) , Huai-zheng Li (李怀正)

{"title":"Determination of urban runoff coefficient using time series inverse modeling","authors":"Hai-long Yin (尹海龙) , Zhi-chao Zhao (赵志超) , Ruoqian Wang , Zu-xin Xu (徐祖信) , Huai-zheng Li (李怀正)","doi":"10.1016/S1001-6058(16)60803-X","DOIUrl":"10.1016/S1001-6058(16)60803-X","url":null,"abstract":"<div><p>Runoff coefficient is an important parameter for the decision support of urban stormwater management. However, factors like comprehensive land-use type, variable spatial elevation, dynamic rainfall and groundwater elevation, make the direct estimation of runoff coefficient difficult. This paper presented a novel method to estimate the urban runoff coefficient using the inverse method, where observed time-series catchment outfall flow volume was employed as input for the water balance model and runoff coefficients of different catchments were treated as unknown parameters. A developed constrained minimization objective function was combined to solve the model and minimized error between observed and modeled outfall flow is satisfactory for the presenting of a set of runoff coefficients. Estimated runoff coefficients for the urban catchments in Shanghai downtown area demonstrated that practice of low impact design could play an important role in reducing the urban runoff.</p></div>","PeriodicalId":66131,"journal":{"name":"水动力学研究与进展:英文版","volume":"29 5","pages":"Pages 898-901"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1001-6058(16)60803-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4055668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 9

BEM for wave interaction with structures and low storage accelerated methods for large scale computation 波与结构相互作用的边界元法和大规模计算的低存储加速方法

3区工程技术

水动力学研究与进展:英文版 Pub Date : 2017-10-01 DOI: 10.1016/S1001-6058(16)60786-2

Bin Teng (滕斌), Ying Gou (勾莹)

{"title":"BEM for wave interaction with structures and low storage accelerated methods for large scale computation","authors":"Bin Teng (滕斌), Ying Gou (勾莹)","doi":"10.1016/S1001-6058(16)60786-2","DOIUrl":"10.1016/S1001-6058(16)60786-2","url":null,"abstract":"<div><p>The boundary element method (BEM) is a main method for analyzing the interactions between the waves and the marine structures. As with the BEM, a set of linear equations are generated with a full matrix, the required calculations and storage increase rapidly with the increase of the structure scale. Thus, an accelerated method with a low storage is desirable for the wave interaction with a very large structure. A systematic review is given in this paper for the BEM for solving the problem of the wave interaction with a large scale structure. Various integral equations are derived based on different Green functions, the advantages and disadvantages of different discretization schemes of the integral equations by the constant panels, the higher order elements, and the spline functions are discussed. For the higher order element discretization method, the special concerns are given to the numerical calculations of the single-layer potential, the double layer potential and the solid angle coefficients. For a large scale computation problem such as the wave interaction with a very large structure or a large number of bodies, the BEMs with the FMM and pFFT accelerations are discussed, respectively, including the principles of the FMM and the pFFT, and their implementations in various integral equations with different Green functions. Finally, some potential applications of the acceleration methods for problems with large scale computations in the ocean and coastal engineering are introduced.</p></div>","PeriodicalId":66131,"journal":{"name":"水动力学研究与进展:英文版","volume":"29 5","pages":"Pages 748-762"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1001-6058(16)60786-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4056446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10