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浅水波方程模型与奇非线性行波方程解的动力学行为及精确的参数表示:动力系统方法
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作者 李继彬 《四川师范大学学报(自然科学版)》 CAS 2024年第4期451-468,共18页
首先,介绍在重力作用下,无旋、无黏性和不可压缩的流体的表面波传播的一维(或两维单向)浅水波运动的各种不同模型(PDE),这些模型对应的行波系统一般是奇平面动力系统.其次,用著名的广义Camassa-Holm方程作为例子,通过对应的行波系统的... 首先,介绍在重力作用下,无旋、无黏性和不可压缩的流体的表面波传播的一维(或两维单向)浅水波运动的各种不同模型(PDE),这些模型对应的行波系统一般是奇平面动力系统.其次,用著名的广义Camassa-Holm方程作为例子,通过对应的行波系统的精确解来研究该方程的尖孤子、周期尖波、伪尖孤子、伪周期尖波及有界破缺波解的存在性.第三,应用动力系统分支理论和奇摄动几何理论相结合的方法,建立了奇非线性行波方程研究的理论和方法,介绍奇非线性行波动力学行为的2个主要定理,完整地解决了波的光滑性与非光滑性、完整性和破缺性的判定问题.第四,介绍当伴随正则系统直线解上的奇点是结点时,如何用相轨道识别对应的波形,并研究一个非线性水波方程,获得该系统的各型光滑的孤立波和周期波在不同参数条件下的存在性和精确的参数表示. 展开更多
关键词 浅水波方程模型 广义CAMASSA-HOLM方程 奇非线性行方程 分枝 动力系统方法
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PODEn4DVar对松弛系数和局地化半径的敏感性
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作者 宋海清 盛炎平 《北京信息科技大学学报(自然科学版)》 2012年第3期15-20,共6页
针对松弛系数和局地化半径的敏感性对PODEn4DVar同化方法性能的影响,以浅水波方程作为预报模型,测试了其对不同松弛系数α和局地化半径R的敏感性,获得了不同模型误差情形下该方法同化时产生的均方根误差变化情况,确定了不同模型误差时... 针对松弛系数和局地化半径的敏感性对PODEn4DVar同化方法性能的影响,以浅水波方程作为预报模型,测试了其对不同松弛系数α和局地化半径R的敏感性,获得了不同模型误差情形下该方法同化时产生的均方根误差变化情况,确定了不同模型误差时的最优松弛系数α和局地化半径R。实验结果表明,在模型有误差时,PODEn4DVar同化方法对参数地选取很敏感。选取最优参数值后,同化精度有了明显提高。 展开更多
关键词 本征正交分解的集合四维交分同化 数据同化 松弛系数 局地化半径 浅水波方程模型
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N-Fold Darboux Transformation and Bidirectional Solitons for Whitham-Broer-Kaup Model in Shallow Water
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作者 王雷 高以天 +3 位作者 盖晓玲 孟得新 吕兴 于鑫 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第3期413-422,共10页
Under investigation in this paper is the Whitham-Broer-Kaup (WBK) system, which describes the dispersive long wave in shallow water. Through a variable transformation, the WBK system is casted into a general Broer-Kau... Under investigation in this paper is the Whitham-Broer-Kaup (WBK) system, which describes the dispersive long wave in shallow water. Through a variable transformation, the WBK system is casted into a general Broer-Kaup system whose Lax pair can be derived by the Ablowitz-Kaup-Newell-Segur technology. With symbolic computation, based on the aforementioned Lax pair, the N-fold Darboux transformation is constructed with a gauge transformation and the multi-soliton solutions are obtained. Finally, the elastic interactions of the two-soliton solutions (including the head-on and overtaking collisions) for the WBK system are graphically studied. Those multi-soliton collisions can beused to illustrate the bidirectional propagation of the waves in shallow water. 展开更多
关键词 Whitham Broer-Kaup system Bidirectional solitons Multi-soliton solutions N-fold Darboux transformation Lax pair
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Integrating 1D and 2D hydrodynamic,sediment transport model for dam-break flow using finite volume method 被引量:3
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作者 ZHANG MingLiang XU YuanYuan +1 位作者 HAO ZiNing QIAO Yang 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2014年第4期774-783,共10页
The purpose of this study is to set up a dynamically linked 1D and 2D hydrodynamic and sediment transport models for dam break flow.The 1D-2D coupling model solves the generalized shallow water equations,the non-equil... The purpose of this study is to set up a dynamically linked 1D and 2D hydrodynamic and sediment transport models for dam break flow.The 1D-2D coupling model solves the generalized shallow water equations,the non-equilibrium sediment transport and bed change equations in a coupled fashion using an explicit finite volume method.It considers interactions among transient flow,strong sediment transport and rapid bed change by including bed change and variable flow density in the flow continuity and momentum equations.An unstructured Quadtree rectangular grid with local refinement is used in the 2D model.The intercell flux is computed by the HLL approximate Riemann solver with shock captured capability for computing the dry-to-wet interface for all models.The effects of pressure and gravity are included in source term in this coupling model which can simplify the computation and eliminate numerical imbalance between source and flux terms.The developed model has been tested against experimental and real-life case of dam-break flow over fix bed and movable bed.The results are compared with analytical solution and measured data with good agreement.The simulation results demonstrate that the coupling model is capable of calculating the flow,erosion and deposition for dam break flows in complicated natural domains. 展开更多
关键词 1D/2D coupling model finite volume method HLL approximate Riemann solver non-equilibrium sediment transport
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