检索结果-南通市图书馆

Surface characters of internal waves generated by Rankine ovoid

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2006年第5期22卷 417-423页

作者： zhaoting xu xu Chen Izolda V. Sturova Instituie of Physical Oceanography and Physical Oceanography Laboratory Ocean University of ChinaQingdao 266003 China Lafrentyev Institute of Hydrodynamics Russian Academy of ScienceNovosibirsk 630090 Russia

A linear theory on the internal waves generated in the stratified fluid with a pycnocline is presented in this paper. The internal wave fields such as the velocity fields in the stratified fluid and velocity gradient fields at the free surface are also investigated by means of the theoretical and numerical method. From the numerical results, it is shown that the internal wave generated by horizontally moving Rankine ovoid is a sort of trapped wave which propagates in a wave guide, and its waveform is a kind of Mach front-type internal wave in the pycnocline. Influence of the internal wave on the flow fields at the free surface is represented by the velocity gradient fields resulted from the internal waves generated by motion of the Rankine ovoid. At the same time, it is also shown that under the hypothesis of inviscid fluid, the synchronism between the surface velocity gradient fields at the free surface and the internal wave fields in the fluid is retained. This theory opens a possibility to study further the modulated spectrum of the Bragg waves at the free surface.

关键词： Internal wave Rankine ovoid Strtified flow Pycnocline

Numerical modeling on the interaction of internal solitary wave with slope-shelf and modal analysis

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2007年第6期26卷 139-149页

作者： LI Qun xu zhaoting CHEN xu YU Jia Physical Oceanography Laboratory and Institute of Physical Oceanography Ocean University of China Qingdao 266100 China

On the basis of a nonhydrostatic numerical model, the interaction of internal solitary wave with slope - shelf was studied. The breaking and polarity transformation were analyzed. A ＂kink＂ structure, due to shoaling topography and higher nonlinear effect, was found to be generated by the leading wave before breaking. Coherent vortex shedding behind the leading wave was presented. The evolution characteristics of the modal structure were analyzed based on the empirical orthogonal function method. The modal structure was complicated due to the effect of the variable topography, especially when breaking occurred. In the performed experiments, the contributions to the total variance from higher mode jumped from no more than 20% to over 40%.

关键词： internal solitary wave modal structure empirical orthogonal function

A correction of the 2D KdV equation of Djordjevic & Redekopp in exponentially stratified fluid

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2005年第4期21卷 346-352页

作者： zhaoting xu Guojin Shen Samuel Shan-pu Shen Institute Of Physical Oceanography and Physical Oceanography Laboratory Ocean University of China Qingdao 266003 China Department of Mathematics and Statistics Science University of Alberta Edmonton Alberta T6G 2G 1 Canada

To further study the nal solitons on the continental fission laws of initial intershelf/slope, we rederive and correct the 2D KdV equation of Djordjevic ＆ Redekopp for exponentially stratified fluid （or ocean） and with twodimensional topography. Through a combination of theoretical study and numerical experiments, we show that solitons in the odd vertical modes can fission. However, because of the corrections, the fission conditions are different from those of Djordjevic ＆ Redekopp. The even modes cannot fission unless the initial internal solitons propagate from shallow sea to deep sea. This conclusion is entirely opposite to that of Djordjevic ＆ Redekopp.

关键词： Internal wave Soliton Fission 2D KdV equation

UNCONVENTIONAL GURTIN-TYPE VARIATIONAL PRINCIPLES FOR FINITE DEFORMATION ELASTODYNAMICS

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2003年第1期16卷 1-7页

作者： xu zhaoting xu Hao and Samuel Shan-pu Shen Zhongshan Univ Dept Appl Mech & Engn Guangzhou 510275 Peoples R China

A theory of tailing wavetrain generation for the precursor soliton generation in two-layer flow is presented by using averaged KdV equations (AKdV), which are derived by the authors in terms of Whitham's method of averaging[1,2]. From the AKdV equations, group velocities of the tailing wavetrain generation are obtained by means of generating conditions of the tailing wavetrains, furthermore an analytical solution of the tailing wavetrain generation is found theoretically. A comparison between the theoretical and numerical results is carried out in the present paper, which shows that the theoretical results are in good agreement with the numerical ones, obtained from the fKdV equation in two-layer flow with the depth of unity in the rest.

关键词： tailing wavetrain group velocity soliton two layer flow

Numerical Simulation on the Interaction of an Internal Solitary Wave with a Step-Type Topography

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean University of China 2008年第2期7卷 119-123页

作者： xu zhaoting LI Qun CHEN xu YU Jia Physical Oceanography Laboratory and Institute of Physical Oceanography Ocean University of China Qingdao 266100 P R. China

Based on a nonhydrostatic numerical ocean model developed by one of the authors, the interaction of an internal solitary wave with a step-type topography was investigated. Over the step topography, the flow pattern could be classified into three catego- ries: 1) the propagation and spatial structure of the internal solitary wave was little influenced by the bottom topography, 2) the in- ternal solitary wave was significantly distorted by the blocking effect of the topography without the occurrence of wave breaking and 3) the internal solitary wave was broken as it encountered and passed over the bottom topography. A detailed description of the processes leading to wave breaking is given in this paper together with energy budget analysis. The results revealed that the maxi- mum of the energy dissipation rate is no more than 40%, which is consistent with available experimental data.

关键词：数字模拟成层流量独立波地形学

On hydraulic falls of single-layer flow

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 1996年第1期15卷 19-30页

作者： xu zhaoting Tian Jiwei Lou Shunli andSamuel Shan pn Shen Institute of Physical Oceanography Physical Oceanography Laboratory Ocean University of Qingdao Qingdao 266003 China Department of Mathematics Institute of Applied Mathematics University of Alberta Edmonton Alta. T6G 2G1 Canada

Hydraulic falls of single-layer now are determined theoretically in terms of a time-dependent averaged fKdV equation(AfKdV equation)in phase coordinate. From the theory of the present paper it was known that difference of the asymptotic mean levels upstream and downsream at the subcritical cutoff points is just equal to a subcritical value of the AfKdV equation An experiment is carried out to examine the theoretical results. From comparison between theoreticaland experimental results, it was shown that they are in good *** the same time, it should be pointed out that the theory of the present paper is agreement with the experimental and numerical results of Forbes and can be employed to find the generating properties of the precursor solitons at near-resonance.

关键词： Hydraulic fall fKdV equation subcritical cutoff point single-layer flow

An infinity of conservation laws of fKdV equation

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 1997年第1期16卷 19-28页

作者： xu zhaoting, xu Yu and Tian Jiwei Institute of Physical Oceanography and Physical Oceanography Laboratory, Ocean University of Qingdao, Qingdao 266003, China Institute of Physical Oceanography Physical Oceanography Laboratory Ocean University of Qingdao Qingdao 266003 China

An infinity of conservation laws of fKdV equation is derived in terms of the Miura and Gardner's transform. The pseudo-mass and energy theorems are studied by the first two conservation laws. As a typical example, the theoretical mean wave resistance and the regional distribution of energy of the precursor soliton generation are determined by means of the first and the second conservation laws.

关键词： Precursor soliton of fKdV equation an fKdV equation an infinity of conservation laws

On hydraulic falls of two-layer flow

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 1996年第2期15卷 179-191页

作者： xu zhaoting Lou Shunli Tian Jiwei and Samuel Shan pn Shen(Institute of Physical Deeanopaphy and Physical oceanography Laboratory, Ocean University Of Qngdao, Qngdao266003, China Department of Mathematics and Applied Mathematics institute, University of A Institute of Physical Oceanography Physical Oceanography Laboratory Ocean University of Qingdao Qingdao 266003 China Department of Mathematics Applied Mathematics Institute University of Alberta Edmonton Alta. T6G 2G1 Canada

Hydraulic falls and asymptotic mean levels of two-layer flow are determined by means of AfKdV equation in phase coordinate theoretically. By present theory, the hydraulic falls Hf depend on a characteristic value of the MfKdV equation at the subcritical cutoff points It is proved that the differences of the asymptotic mean levels upstream and downstream at the subcritical cutoff points are equal to 2 A relation between and the asymptotic mean levels at the subcritical cutoff points is also found in terms of the solution of the hydraulic falls. Because the AfKdV equation is derived based on the small topography assumption, for semicircular topography the valid region of this theory is α< 0. 35, in which α is radius of the semicircular topography. An experiment is carried out to examine the theory of the present paper. From comparisons between the theoretical and experimental results. it is shown that they are in better agreement. Under conditions of different stratified parameters, the hydraulic falls of two-layer flow are predicted theoretically. This work was supered by the Foundation of the State Education COmmission 'The dynamics of upper ocean'.

关键词： fKdV equation hydraulic fall two-layer flow subcritical cutoff point

在线全文

学校读者我要写书评

暂无评论

轻量化高强度过渡车钩开发研究

智慧轨道交通 2022年第3期59卷 70-73页

作者：徐兆亭中车青岛四方车辆研究所有限公司钩缓事业部青岛266031

本文介绍了一款新型过渡车钩,相比原普通碳钢材质过渡车钩,重量降低30%以上,强度尚有提升,可单人进行搬运、连挂操作,可以满足机车5 km连挂地铁车辆的要求。该过渡车钩采用钛合金材质,具有高强度、轻量化、耐腐蚀的特点,即使表面不做任... 详细信息

本文介绍了一款新型过渡车钩,相比原普通碳钢材质过渡车钩,重量降低30%以上,强度尚有提升,可单人进行搬运、连挂操作,可以满足机车5 km连挂地铁车辆的要求。该过渡车钩采用钛合金材质,具有高强度、轻量化、耐腐蚀的特点,即使表面不做任何防腐处理,仍具有较好的耐腐蚀性能。解决了目前过渡车钩实际应用过程中的部分问题,具有广阔的推广应用前景。阐述了新型过渡车钩的设计研发过程,并对产品样机进行试验、研究,为后续产品的研发及改进提供借鉴。

关键词：过渡车钩轻量化高强度钛合金耐腐蚀