1,862 research outputs found
Corrigendum. Three-dimensional interaction between uniform current and a submerged horizontal cylinder in an ice-covered channel (Journal of Fluid Mechanics (2021) 928 (A4) DOI: 10.1017/jfm.2021.792)
No full textIn the Appendix B of Yang, Wu & Ren (2021), we made the statement that the Green function G has the symmetry property with respect to the field point P(x
1, y
1, z
1) and field point P
0(x
0, y
0, z
0), or G(x
1, y
1, z
1; x
0, y
0, z
0) = G(x
0, y
0, z
0; x
1, y
1, z
1). This is not always correct. The mistake arose from the statement below (B2) that 'Although G and ξ involve only the real part, we may use the whole complex function here'. In the derivations followed, the full complex functions of G
i and ξ
i (i = 0, 1) in (B1) and (B2) were directly used without taking their real parts, which led to an incorrect conclusion. However, it should be noted that when 0 < Fn < Fn
(1)
c , G
i and ξ
i contain only the k
0 component. G
(0)
i is fully real and ξ
(0)
i is fully imaginary, and they can be taken out of the operator Re{}. Therefore, the symmetry property is satisfied within this range. In summary, the symmetry property G(x
1, y
1, z
1; x
0, y
0, z
0) = G(x
0, y
0, z
0; x
1, y
1, z
1) holds only when 0 < Fn < Fn
(1)
c, and it is incorrect when Fn > Fn
(1)
c. This mistake is confined solely to the Appendix B, and it does not affect any other formulas or results presented in the paper.</p
Analysis of Earth Pressure for Retaining Wall and Ultimate Bearing Capacity for Shallow Foundation by Variational Method
No full textVariational Stability Analysis of Cohesive Slope by Applying Boundary Integral Equation Method
No full textSurface wave interaction with floating elastic plates in channels
No full textThe interaction between surface waves and a finite rectangular floating plate in a channel is considered analytically, while the location of the plate is not restricted. The mathematical model is based on the linear velocity potential flow theory for the fluid and the Kirchhoff-Love plate theory for the plate. The problem is converted into an integral equation through using the Green function. The second-order singularity associated with a body with no thickness is treated with the Dirac delta function. The developed scheme is used for case studies of various edge constraints. Extensive results are provided for the hydrodynamic forces acting on the plate and the wave reflection and transmission coefficients. The effects of wave frequency, channel width, plate length, and edge conditions are analyzed, and their physical implications are highlighted. Significant findings comprise the highly oscillatory nature of force curves, influenced by the natural frequencies of the channels and the length of the plate, and substantial effects of edge conditions and the plate position on the results.</p
Hydroelastic wave interaction with a circular crack of an ice-cover in a channel
No full textHydroelastic wave interaction with a circular crack of an ice-cover in a channel together with some related problems is considered, based on the linearized velocity potential theory and Kirchhoff plate theory. The domain decomposition method is adopted in the solution procedure. Two sub-domains are divided by the crack, one below the inner ice sheet and the other below the outer ice sheet. By using the Green function of an ice-covered channel, the velocity potential in the outer domain is established from the source distribution formula over an artificial vertical surface extended from the crack. The source distribution is expanded in both vertical and circumferential directions, which allows the velocity potential to be obtained in an explicit form with unknown coefficients. The velocity potential in the inner domain is expanded into a double series. An orthogonal inner product is used to impose continuity conditions on the artificial vertical surface and the edge conditions at the crack. The derived formulation is not just limited to the circular crack problem but can also be readily used in a variety of other problems, including wave diffraction by a surface-piercing vertical cylinder, polynya and circular disc floating on the free surface in a channel. Extensive results are provided for the forces on the inner ice sheet, the transmission and reflection coefficients. In particular, a detailed analysis is made on their behaviours near the natural frequencies of the channel, and the natural frequencies corresponding to the motion of the inner ice sheet.</p
Interaction between a uniform current and a submerged cylinder in a marginal ice zone
No full textThe interaction between a uniform current with a circular cylinder submerged in a fluid covered by a semi-infinite ice sheet is considered analytically. The ice sheet is modelled as an elastic thin plate, and the fluid flow is described by the linearised velocity potential theory. The Green function or the velocity potential due to a source is first obtained. As the water surface is divided into two semi-infinite parts with different boundary conditions, the Wiener-Hopf method (WHM) offers significant advantages over alternative approaches and is consequently adopted. To do that, the distribution of the roots of the dispersion equation for fluid fully covered by an ice sheet in the complex plane is first analysed systematically, which does not seem to have been done before. The variations of these roots with the Froude number are investigated, especially their effects or factorisation and decomposition required in the WHM. The result is verified by comparing with that obtained from the matched eigenfunction expansion method. Through differentiating the Green function with respect to the source position, the potentials due to multipoles are obtained, which are employed to construct the velocity potential for the circular cylinder. Extensive results are provided for hydrodynamic forces on the cylinder and wave profiles, and some unique features are discussed. In particular, it is found that the forces can be highly oscillatory with the Froude number when the body is below the ice sheet, whereas such an oscillation does not exist when the body is below the free surface.</p
Fabrication and optical properties of periodical structures based on water-developable and tunable La SrMnO resist
No full text“Why did she love her mother’s so?”: L.E.L. Forging Corinne
No full text在十九世紀上半葉歐洲社會對於童話、民間故事的蒐集益加熱烈，民間傳說甚至被視為國族文化的基礎，特別是有關美人魚的傳說逐漸成為跨文化的神話典型之一。此類傳說由政治寓言的縮影，如法國中古傳奇《梅律欣》，轉型為浪漫個人主體追求的代言，如安徒生的《小美人魚》與斯黛夫人的《蔻琳，義大利》。英國女詩人蘭登將梅律欣半人半魚的混雜身體嫁接在蔻琳的聲音上，企求在文學商品化的時代脈動中，鑄煉自身文學的威信，能與當代女詩人的另一典範，有著?虔敬母親?之稱的賀曼絲並駕齊驅。蘭登的自我定義分為三個階段：第一、在〈即興女詩人〉一詩中，蘭登將女詩人蔻琳的即興表演發揮地淋漓盡致，更利用詩人聲音稍縱即逝的特性，她得以擊破流行文學雜誌與年鑑以視覺為賣點的策略。第二、在〈噴泉仙女〉一詩中，蘭登將市場對女性詩人兜售身體的要求，透過梅律欣身體的三重展演，轉化為對她們文字的珍視。第三、〈蔻琳在米賽納角〉一詩則具體而微地體現蘭登如何巧用視覺機制突顯文字的優勢，為斯黛夫人筆下失去義大利詩歌本真的蔻琳賦予聲音。本論文探討蘭登如何與斯黛夫人與賀曼絲這兩位?文學母親?的詩學遺產較勁，以梅律欣的?混合嫁妝?譬喻自己在十九世紀文學商業化潮流下的掙扎。The early decades of the nineteenth century witnessed a renewed interest in the folklore of the mermaid. This period of intensified nation-building and pursuit of individual spirit gradually shifted the political concerns of the medieval romance, such as in the French legend of M?lusine, to the struggle of Romantic author, such as in Corinne, or Italy (1807) by Germaine de Sta?l. Corinne, an improvisatrice of hybrid origin becomes a model for women writers in the nineteenth century. Their responses can be summed up in the polarized paradigm of the poetess represented by Felicia Dorothea Hemans, “the pious mother,” and Letitia Elizabeth Landon, the pretty verse maker.
Landon’s self-definition as a poetess against the model of Corinne develops in three phases in which she adjusts her alignment with her foremothers and finally finds a way out of the impasse bequeathed by them, namely the overwhelming emphasis on the body. First, in “The Improvisatrice,” Landon exploits Corinne’s performative art to exude the visual confines demanded by the popular periodicals and gift annuals. Second, in “The Fairy of the Fountains,” she adapts the matrilineal legend of M?lusine by crafting the word rather than the body of the Fairy into the crux of transgression. Third, in “Corinne at the Cape of Misena,” Landon uses her translation of Corinne’s last song to reinstate her virtuosity. This paper seeks to delineate the ways in which Landon forges her own authority as a new Corinne by capitalizing on the “mingled dower” of M?lusine
Hydroelastic wave diffraction by a vertical circular cylinder standing in a channel with an ice cover
No full textThe problem of hydroelastic wave diffraction by a surface-piercing vertical circular cylinder mounted on the bottom of an ice-covered channel is considered. The ice sheet is modelled as an elastic thin plate with homogeneous properties, while the linearized velocity potential theory is adopted to describe the motion of the fluid. The solution starts from the Green function satisfying all other boundary conditions apart from that on the body surface. This is obtained through applying a Fourier transform in the longitudinal direction of the channel and adopting an eigenfunction expansion in the vertical direction. The boundary conditions on the side walls and ice edges are imposed through an orthogonal product. Through the Green function, the velocity potential due to a surface-piercing structure with arbitrary shape can be expressed through a source distribution formula derived in this work, in which only integrals over the body surface and its interaction line with the ice sheet need to be retained. For a vertical circular cylinder, the unknown source distribution can be expanded further into a Fourier series in the circumferential direction, and then the analytical solution of the velocity potential can be obtained further. Extensive results and discussions are provided for the hydrodynamic forces and vertical shear forces on the cylinder, as well as the deflection and strain of the ice sheet. In particular, the behaviour of the solution near one of the natural frequencies of the channel is investigated in detail
Three-dimensional interaction between uniform current and a submerged horizontal cylinder in an ice-covered channel
No full textThe problem of interaction of a uniform current with a submerged horizontal circular cylinder in an ice-covered channel is considered. The fluid flow is described by linearized velocity potential theory and the ice sheet is treated as a thin elastic plate. The potential due to a source or the Green function satisfying all boundary conditions apart from that on the body surface is first derived. This can be used to derive the boundary integral equation for a body of arbitrary shape. It can also be used to obtain the solution due to multipoles by differentiating the Green function with its position directly. For a transverse circular cylinder, through distributing multipoles along its centre line, the velocity potential can be written in an infinite series with unknown coefficients, which can be determined from the impermeable condition on a body surface. A major feature here is that different from the free surface problem, or a channel without the ice sheet cover, this problem is fully three-dimensional because of the constraints along the intersection of the ice sheet with the channel wall. It has been also confirmed that there is an infinite number of critical speeds. Whenever the current speed passes a critical value, the force on the body and wave pattern change rapidly, and two more wave components are generated at the far-field. Extensive results are provided for hydroelastic waves and hydrodynamic forces when the ice sheet is under different edge conditions, and the insight of their physical features is discussed
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