检索结果-南通市图书馆

Experimental Study on the Performance of Twin Plate Breakwater

在线全文

学校读者我要写书评

暂无评论

China Ocean engineering 2011年第4期25卷 645-656页

作者：郭传胜张宁川李艳阳李靖波房卓崔成 state key laboratory of coastal and offshore engineering Dalian University of Technology

The wave transmission characteristics and wave induced pressures on twin plate breakwater are investigated experimentally in regular and random waves. A total of twenty pressure transducers are fixed on four surfaces of twin plate to measure the wave induced dynamic pressures. The spatial distribution of dynamic wave pressure is given along the surface of the twin plate. The uplift wave force obtained by integrating the hydrodynamic pressure along the structure is presented. Discussed are the influence of different incident wave parameters including the relative plate width B/L, relative wave height Hi / a and relative submergence depth s / a on the non-dimensional dynamic wave pressures and total wave forces. From the investigation, it is found that the optimum transmission coefficient, Kt occurs around B/L = 0.41 - 0.43, and the twin plate breakwater is more effective in different water depths. The maximum of pressure ratio decreases from 1.8 to 1.1 when the relative submergence depth of top plate is increased from -0.8 to ＋0.8.

关键词： twin plate wave pressure vertical wave force relative submergence transmission coefficient

Mechanics Behavior of Ultra High Toughness Cementitious Composites after Freezing and Thawing

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2010年第3期25卷 509-514页

作者：徐世烺 The state key laboratory of coastal and offshore engineering Dalian University of Technology

Mechanical behaviors of UHTCC after freezing and thawing were investigated,and compared with those of steel fiber reinforced concrete（SFRC）,air-entrained concrete（AEC） and ordinary concrete（OC）.Four point bending tests had been applied after different freezing-thawing cycles（0,50,100,150,200 and 300 cycles,respectively）.The results showed that residual flexural strength of UHTCC after 300 freezing-thawing cycles was 10.62 MPa（70% of no freezing thawing ones）,while 1.58 MPa（17% of no freezing thawing ones） for *** toughness of UHTCC decreased by 17%,while 70% for SFRC *** has been demonstrated experimentally that UHTCC without any air-entraining agent could resist freezing-thawing and retain its high toughness characteristic in cold ***,UHTCC could be put into practice for new-built or retrofit of infrastructures in cold regions.

关键词： ultra high toughness cementitious composites cyclic freezing and thawing flexural strength multiple cracking flexural toughness

Oblique and Multi-Directional Random Wave Loads on Vertical Breakwaters

在线全文

学校读者我要写书评

暂无评论

海洋工程：英文版 2003年第2期17卷 189-202页

作者：俞聿修李本霞张宁川 state key laboratory of coastal and offshore engineering Dalian University of Technology

Extensive 3-D model tests have been performed to study the effects of wave obliquity and multi-directionality on the wave loads acting on vertical breakwaters. The variation of horizontal and uplift forces acting on an unit length of a breakwater with wave direction, the longitudinal distribution of wave forces, as well as the longitudinal load reduction are analyzed. Some empirical formulae of the longitudinal distribution coefficient and the longitudinal load reduction factor are presented for practical use.

关键词： vertical breakwaters oblique wave multi-directional random wave longitudinal distribution wave forces longitudinal load reduction

Experimental Study on Performance of Plain Concrete Due to Triaxial Variable-Amplitude Tension-Compression Cyclic Loading

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2005年第3期20卷 104-109页

作者：曹伟 state key laboratory of coastal and offshore engineering Dalian University of Technology

An experimental study on performance of plain concrete under triaxial constant-amplitude and variable amplitude tension- compression cyclic loadings was carded out. The low level of the cyclic stress is 0. 2f and the upper level ranges between 0. 20f and 0. 55f., while the constant lateral pressure is 0. 3 f . The specimen failure mode, the three-stage evolution rule of the longitudinal strains and the damage evolution law under cyclic loading were analyzed. Furthermore, Miner＇s rule is proved not to be applicable to the cyclic loading conditions, hereby, a nonlinear cumulative damage model was established. Based on the model the remaining fatigue life was evaluated. The comparison whh the experiment resuhs shaws that the model is of better precision and applicability.

关键词： concrete triaxial tension-compression Cyclic loading three-stage evolution rule nonlinear cumulative damage model

Numerical Studies on the Generation and Propagation of Tsunami Waves Based on the High-Order Spectral Method

在线全文

学校读者我要写书评

暂无评论

China Ocean engineering 2022年第2期36卷 268-278页

作者： HAO Jian LI Jin-xuan LIU Shu-xue WANG Lei state key laboratory of coastal and offshore engineering Dalian University of TechnologyDalian 116024China

An effective numerical model for wave propagation over three-dimensional(3D)bathymetry was developed based on the High-Order Spectral(HOS)method and combined with a moving bottom *** on this model,tsunami waves caused by various mechanisms were simulated and ***-dimensional bed upthrust and the effect of the uplift velocity of the bathymetry on the wave profiles of tsunami waves were ***,tsunami waves caused by 3D submarine slides were generated and the effects of the slide velocity,slide dimension and water depth on the tsunami waves were *** on wavelet analysis,the properties of the tsunami wave propagation were *** results show that the bottom movement can significantly affect the generation and propagation of tsunami waves and the studies could help understand the mechanisms of tsunamis caused by a moving bottom boundary.

关键词： tsunami waves High-Order Spectral(HOS)method moving bottom boundary wavelet analysis

ABRUPT DEFLECTED SUPERCRITICAL WATER FLOW IN SLOPED CHANNELS

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2008年第3期20卷 293-298页

作者： LIU Ya-kun NI Han-gen state key laboratory of coastal and offshore engineering Dalian University of Technology Dalian 116024China

The effect of the bottom slope on abrupt deflected supercritical water flow was experimentally and theoretically studied. Model tests were conducted in a flume of 1.2 m wide and 2.6 m long with sloped bottom at an angle 35.54°, its length of deflector was 0.2 m and the deflection angles were 15° and 30°. An approximate method for calculating the shock wave angle and depth ratio of the abrupt deflected supercritical water flow was suggested, and a correction coefficient for the hydrodynamic pressure was introduced to generalize the momentum equation in the direction perpendicular to the shock front. It must be noticed that in the sloped channel the shock wave angle and the depth ratio are no longer constant as those in the horizontal channels, but slowly change along the shock front. The calculated results are in good agreement with measured data.

关键词： shock wave abrupt deflection of supercritical water flow slopping channel

ABRUPT DEFLECTED SUPERCRITICAL WATER FLOW-REVISED THEORY OF SHOCK WAVE

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2006年第1期18卷 32-39页

作者： NI Han-gen LIU Ya-kun state key laboratory of coastal and offshore engineering Dalian University of Technology Dalian 116024 China

The shock wave angle and depth ratio of the abrupt deflected supercritical water flow due to deflector was investigated experimentally and theoretically. A correction coefficient of the hydro-dynamic pressure ξ was introduced to generalize the momentum equation in the perpendicular direction to the shock front. An extensive series of tests were conducted in a 1 m wide flume with the Froude number ranging from 1.70 to 8.37, the deflection angle ranging from 5° to 40° and the length of deflector ranging from 0.28 m to 1 m. A dimensionless parameter K was defined to depict the ratio of the flow height to flow thickness. Test results show that the val ue of ~, the correction coefficient of the non-hydrostatic pres- sure distribution, decreases with the increase of the value of K An empirical relationship between the value of ξ and the val ue of K was proposed. It is indicated that the relative errors of the results calculated by the revised theory is much smaller than that obtained from the Ippen theory. Finally, a simple explicit expression was suggested to calculate the shock wave height ratio in consideration of the effect of the non-hydrostatic pressure distribution.

关键词： theory of shock wave abrupt deflection of supercritical flow trajectory type energy dissipater

A STUDY ON UNSTEADY SEEPAGE FLOW THROUGH DAM

在线全文

学校读者我要写书评

暂无评论

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

A NEW NUMERICAL WAVE FLUME COMBINING THE 0-1 TYPE BEM AND THE VOF METHOD

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2012年第4期24卷 506-517页

作者： GUO Li-dong SUN Da-peng WU Hao state key laboratory of coastal and offshore engineering Dalian University of TechnologyDalian 116024China

A new coupling numerical wave model, based on both the Boundary Element Method （BEM） and the Volume Of Fluid （VOF） method, is established by taking advantages of the both methods to solve the wave-structure interaction problems. In this model, the wave transformation in front of structures is calculated by the 0-1 type BEM, and the intense wave motions near the structures are calculated by the VOF method. In this paper, the characteristics of the BEM and the VOF method are discussed first, and then the coupling treatments are described in detail. In the end, the accuracy and the validity of the coupling model are examined by comparing the numerical results with experiment results and other numerical results available for the interactions between regular waves with a monolayer horizontal plate.

关键词： Boundary Element Method (BEM) Volume Of Fuid (VOF) method coupling numerical wave model horizontal plate