A panel method is described for calculating potential flow around near-surface submarines. The method uses Havelock sources which automatically satisfy the linearized free-surface boundary condition. Outputs from the ...A panel method is described for calculating potential flow around near-surface submarines. The method uses Havelock sources which automatically satisfy the linearized free-surface boundary condition. Outputs from the method include pressure field, pressure drag, wave resistance, vertical force, trim moment and wave pattern. Comparisons are made with model tests for wave resistance of Series 58 and DARPA SUBOFF hulls, as well as with wave resistance, lift force and trim moment of three length-to-diameter variants of the DSTO Joubert submarine hull. It is found that the Havelock source panel method is capable of determining with reasonable accuracy wave resistance, vertical force and trim moment for submarine hulls. Further experimental data are required in order to assess the accuracy of the method for pressure field and wave pattern prediction. The method is implemented in the computer code“HullWave”and offers potential advantages over RANS-CFD codes in terms of speed, simplicity and robustness.展开更多
The effect of porosity on surface wave scattering by a vertical porous barrier over a rectangular trench is studied here under the assumption of linearized theory of water waves.The fluid region is divided into four s...The effect of porosity on surface wave scattering by a vertical porous barrier over a rectangular trench is studied here under the assumption of linearized theory of water waves.The fluid region is divided into four subregions depending on the position of the barrier and the trench.Using the Havelock’s expansion of water wave potential in different regions along with suitable matching conditions at the interface of different regions,the problem is formulated in terms of three integral equations.Considering the edge conditions at the submerged end of the barrier and at the edges of the trench,these integral equations are solved using multi-term Galerkin approximation technique taking orthogonal Chebyshev’s polynomials and ultra-spherical Gegenbauer polynomial as its basis function and also simple polynomial as basis function.Using the solutions of the integral equations,the reflection coefficient,transmission coefficient,energy dissipation coefficient and horizontal wave force are determined and depicted graphically.It was observed that the rate of convergence of the Galerkin method in computing the reflection coefficient,considering special functions as basis function is more than the simple polynomial as basis function.The change of porous parameter of the barrier and variation of trench width and height significantly contribute to the change in the scattering coefficients and the hydrodynamic force.The present results are likely to play a crucial role in the analysis of surface wave propagation in oceans involving porous barrier over submarine trench.展开更多
This article explores and re-evaluates Zhang Jingsheng＇s views on sex education and aesthetic education, as revealed in his book Sexual Histories and in articles that he published in the journal New Culture. His endo...This article explores and re-evaluates Zhang Jingsheng＇s views on sex education and aesthetic education, as revealed in his book Sexual Histories and in articles that he published in the journal New Culture. His endorsement of sex education and aesthetic education constructed a sexual discourse, advocating the redefinition- of Chinese men and women＇s gender and sexuality through knowledge/power. Zhang Jingsheng highly valued eugenics and ＂aesthetic sexual intercourse,＂ and he attempted to use sex education to improve Chinese people＇s innate physical weakness and their ＂androgynous＂ sexual characteristics. By prescribing an aesthetic education that covered all fundamental aspects of life, he also attempted to remedy what he saw as the inadequate or inverted models of masculinity and femininity available to Chinese men and women. Furthermore, by collecting and analyzing articles solicited for Sexual Histories and letters addressed to New Culture, he discussed how to cure the sexual perversions that were associated with Chinese men and women＇s sexualities. Finally, this article compares the contents of New Culture with the discourses （in Chinese and other languages） on sexual difference published in other Chinese journals in the 1920s, including how the discourses on sexual difference by Havelock Ellis and Edward Carpenter were translated into the modern Chinese context. The article concludes that the contributors to New Culture held unified opinions on the issues of homosexuality and women＇s liberation. Thus, in comparison with journals such as The Chinese Educational Review, The Ladies ＇Journal, and New Women, New Culture was less tolerant of divergent opinions. Although Zhang supported sexual liberation, he nonetheless sought to eliminate homosexuality from the aesthetic society that he envisioned. His idea of sexual liberation tended to signify women＇s liberation and excluded a homosexual agenda because he was homophobic. For most of the May Fourth Generation, including Zhang Jingsheng,sexual and women＇s liberation were not equivalent to self-liberation. Instead, the concepts of sexual liberation and women＇s liberation were invoked to re-code the bodies of Chinese men and women, with the aim of creating a ＂Strong Breed to Rescue the Nation.＂展开更多
文摘A panel method is described for calculating potential flow around near-surface submarines. The method uses Havelock sources which automatically satisfy the linearized free-surface boundary condition. Outputs from the method include pressure field, pressure drag, wave resistance, vertical force, trim moment and wave pattern. Comparisons are made with model tests for wave resistance of Series 58 and DARPA SUBOFF hulls, as well as with wave resistance, lift force and trim moment of three length-to-diameter variants of the DSTO Joubert submarine hull. It is found that the Havelock source panel method is capable of determining with reasonable accuracy wave resistance, vertical force and trim moment for submarine hulls. Further experimental data are required in order to assess the accuracy of the method for pressure field and wave pattern prediction. The method is implemented in the computer code“HullWave”and offers potential advantages over RANS-CFD codes in terms of speed, simplicity and robustness.
文摘The effect of porosity on surface wave scattering by a vertical porous barrier over a rectangular trench is studied here under the assumption of linearized theory of water waves.The fluid region is divided into four subregions depending on the position of the barrier and the trench.Using the Havelock’s expansion of water wave potential in different regions along with suitable matching conditions at the interface of different regions,the problem is formulated in terms of three integral equations.Considering the edge conditions at the submerged end of the barrier and at the edges of the trench,these integral equations are solved using multi-term Galerkin approximation technique taking orthogonal Chebyshev’s polynomials and ultra-spherical Gegenbauer polynomial as its basis function and also simple polynomial as basis function.Using the solutions of the integral equations,the reflection coefficient,transmission coefficient,energy dissipation coefficient and horizontal wave force are determined and depicted graphically.It was observed that the rate of convergence of the Galerkin method in computing the reflection coefficient,considering special functions as basis function is more than the simple polynomial as basis function.The change of porous parameter of the barrier and variation of trench width and height significantly contribute to the change in the scattering coefficients and the hydrodynamic force.The present results are likely to play a crucial role in the analysis of surface wave propagation in oceans involving porous barrier over submarine trench.
文摘This article explores and re-evaluates Zhang Jingsheng＇s views on sex education and aesthetic education, as revealed in his book Sexual Histories and in articles that he published in the journal New Culture. His endorsement of sex education and aesthetic education constructed a sexual discourse, advocating the redefinition- of Chinese men and women＇s gender and sexuality through knowledge/power. Zhang Jingsheng highly valued eugenics and ＂aesthetic sexual intercourse,＂ and he attempted to use sex education to improve Chinese people＇s innate physical weakness and their ＂androgynous＂ sexual characteristics. By prescribing an aesthetic education that covered all fundamental aspects of life, he also attempted to remedy what he saw as the inadequate or inverted models of masculinity and femininity available to Chinese men and women. Furthermore, by collecting and analyzing articles solicited for Sexual Histories and letters addressed to New Culture, he discussed how to cure the sexual perversions that were associated with Chinese men and women＇s sexualities. Finally, this article compares the contents of New Culture with the discourses （in Chinese and other languages） on sexual difference published in other Chinese journals in the 1920s, including how the discourses on sexual difference by Havelock Ellis and Edward Carpenter were translated into the modern Chinese context. The article concludes that the contributors to New Culture held unified opinions on the issues of homosexuality and women＇s liberation. Thus, in comparison with journals such as The Chinese Educational Review, The Ladies ＇Journal, and New Women, New Culture was less tolerant of divergent opinions. Although Zhang supported sexual liberation, he nonetheless sought to eliminate homosexuality from the aesthetic society that he envisioned. His idea of sexual liberation tended to signify women＇s liberation and excluded a homosexual agenda because he was homophobic. For most of the May Fourth Generation, including Zhang Jingsheng,sexual and women＇s liberation were not equivalent to self-liberation. Instead, the concepts of sexual liberation and women＇s liberation were invoked to re-code the bodies of Chinese men and women, with the aim of creating a ＂Strong Breed to Rescue the Nation.＂
