The hydrodynamic coefficients C-d and C-m are not only dependent on the size of slender cylinder, its location in water, KC number and Re number, but also vary with environmental conditions, i.e., in regular waves or ...The hydrodynamic coefficients C-d and C-m are not only dependent on the size of slender cylinder, its location in water, KC number and Re number, but also vary with environmental conditions, i.e., in regular waves or in irregular waves, in pure waves or in wave-current coexisting field. In this paper, the normalization of hydrodynamic coefficients for various environmental conditions is discussed. When a proper definition of KC number and proper characteristic values of irregular waves are used, a unified relationship between C-d, C-m and KC number for regular waves, irregular waves, pure waves and wave-current coexisting field can be obtained.展开更多
This study investigates the hydro-elastic behaviors of fully submerged horizontal cylinders in different regular waves.Two methods were proposed and compared in this study.The first method was based on potential theor...This study investigates the hydro-elastic behaviors of fully submerged horizontal cylinders in different regular waves.Two methods were proposed and compared in this study.The first method was based on potential theory in frequency domain and the discrete-module-beam(DMB)method,which discretizes a floating elastic structure into a sufficient number of rigid bodies while simultaneously representing the elastic behavior from beam elements with Euler-Bernoulli beam and Saint-Venant torsion.Moreover,the Morison method in time domain was employed;this method estimates wave forces from the semi-empirical Morison equation,and the elastic behavior is embodied by massless axial,bending,and torsional springs.Various parametric studies on cylinder diameter,submergence depth,and wave direction were conducted.Wave forces,dry/wet mode shapes/natural frequencies,and dynamic motions are presented and analyzed.展开更多
Diagrams as a visual technique played a key role in early modern natural history.Robert Morison,a Scottish botanist and the first Professor of Botany at Oxford University,made a noteworthy early attempt in the 17th ce...Diagrams as a visual technique played a key role in early modern natural history.Robert Morison,a Scottish botanist and the first Professor of Botany at Oxford University,made a noteworthy early attempt in the 17th century to promote the use of diagrams in plant taxonomy.By pioneering the use of diagrams as the core of his botanical monographs,Morison inverted the order in which text and diagrams are read in natural history books and made diagrams more than a mere adjunct to the main text.Morison also consciously aligned the structure of the diagrams with the spatial arrangement of his seed collection and the Oxford Botanic Garden,so that the diagrams functioned productively as a means of bridging difierent botanical practices and retrieving information from multiple aspects.Morison’s appropriation and mobilisation of the diagrammatic mode of representation that originated in the Middle Ages helped pave the way for the diagram,as a visual language between textuality and pictoriality,to become prevalent amongst early modern naturalists.展开更多
基金National Natural Science Foundation of China(No.59779005)
文摘The hydrodynamic coefficients C-d and C-m are not only dependent on the size of slender cylinder, its location in water, KC number and Re number, but also vary with environmental conditions, i.e., in regular waves or in irregular waves, in pure waves or in wave-current coexisting field. In this paper, the normalization of hydrodynamic coefficients for various environmental conditions is discussed. When a proper definition of KC number and proper characteristic values of irregular waves are used, a unified relationship between C-d, C-m and KC number for regular waves, irregular waves, pure waves and wave-current coexisting field can be obtained.
文摘This study investigates the hydro-elastic behaviors of fully submerged horizontal cylinders in different regular waves.Two methods were proposed and compared in this study.The first method was based on potential theory in frequency domain and the discrete-module-beam(DMB)method,which discretizes a floating elastic structure into a sufficient number of rigid bodies while simultaneously representing the elastic behavior from beam elements with Euler-Bernoulli beam and Saint-Venant torsion.Moreover,the Morison method in time domain was employed;this method estimates wave forces from the semi-empirical Morison equation,and the elastic behavior is embodied by massless axial,bending,and torsional springs.Various parametric studies on cylinder diameter,submergence depth,and wave direction were conducted.Wave forces,dry/wet mode shapes/natural frequencies,and dynamic motions are presented and analyzed.
文摘Diagrams as a visual technique played a key role in early modern natural history.Robert Morison,a Scottish botanist and the first Professor of Botany at Oxford University,made a noteworthy early attempt in the 17th century to promote the use of diagrams in plant taxonomy.By pioneering the use of diagrams as the core of his botanical monographs,Morison inverted the order in which text and diagrams are read in natural history books and made diagrams more than a mere adjunct to the main text.Morison also consciously aligned the structure of the diagrams with the spatial arrangement of his seed collection and the Oxford Botanic Garden,so that the diagrams functioned productively as a means of bridging difierent botanical practices and retrieving information from multiple aspects.Morison’s appropriation and mobilisation of the diagrammatic mode of representation that originated in the Middle Ages helped pave the way for the diagram,as a visual language between textuality and pictoriality,to become prevalent amongst early modern naturalists.
