Documents disponibles écrits par cet auteur

Numerical model for flood routing with a Cartesian cut-cell domain / Hyung-Jun Kim in Journal of hydraulic research, Vol. 49 N° 2 (Mars/Avril 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 2 (Mars/Avril 2011) . - pp. 205-212 Titre : Numerical model for flood routing with a Cartesian cut-cell domain Type de document : texte imprimé Auteurs : Hyung-Jun Kim, Auteur ; Yong-Sik Cho, Auteur Année de publication : 2011 Article en page(s) : pp. 205-212 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Cut-cell  system  Dam-break  Finite  volume  method  Shallow-water  Shock-capturing Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : Flood risk analysis requires adequate numerical modeling to estimate the inundation depth and velocity in a wide-ranging study area. Thus, accurate, simple, and efficient numerical models with adequate mesh systems are needed for large-scale flood simulations. A numerical model based on a finite volume approach with the Cartesian cut-cell method is adopted herein to solve the shallow-water equations. To improve the representation of the flow domain, a modified cut-cell technique is suggested. The modified cut-cell mesh can be generated by a mesh merging process which needs two or more cut-cell meshes for different flow characteristic domains such as a compound meandering channel with steps. The modified cut-cell mesh indicated a reasonable flow domain to represent complicated domains. To verify the accuracy and stability of the present numerical model, various tests were performed and the obtained predictions compared with available exact solutions and laboratory measurements. A very reasonable agreement was observed. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2010.547037 [article] Numerical model for flood routing with a Cartesian cut-cell domain [texte imprimé] / Hyung-Jun Kim, Auteur ; Yong-Sik Cho, Auteur . - 2011 . - pp. 205-212. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 2 (Mars/Avril 2011) . - pp. 205-212 Mots-clés : Cut-cell  system  Dam-break  Finite  volume  method  Shallow-water  Shock-capturing Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : Flood risk analysis requires adequate numerical modeling to estimate the inundation depth and velocity in a wide-ranging study area. Thus, accurate, simple, and efficient numerical models with adequate mesh systems are needed for large-scale flood simulations. A numerical model based on a finite volume approach with the Cartesian cut-cell method is adopted herein to solve the shallow-water equations. To improve the representation of the flow domain, a modified cut-cell technique is suggested. The modified cut-cell mesh can be generated by a mesh merging process which needs two or more cut-cell meshes for different flow characteristic domains such as a compound meandering channel with steps. The modified cut-cell mesh indicated a reasonable flow domain to represent complicated domains. To verify the accuracy and stability of the present numerical model, various tests were performed and the obtained predictions compared with available exact solutions and laboratory measurements. A very reasonable agreement was observed. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2010.547037

Numerical simulation of shallow-water flow using a modified cartesian cut-cell approach / Hyung-Jun Kim in Journal of engineering mechanics, Vol. 136 N° 3 (Mars 2010) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 136 N° 3 (Mars 2010) . - pp. 399-404 Titre : Numerical simulation of shallow-water flow using a modified cartesian cut-cell approach Type de document : texte imprimé Auteurs : Hyung-Jun Kim, Auteur ; Lee, Jin Woo, Auteur ; Yong-Sik Cho, Auteur Article en page(s) : pp. 399-404 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Dam  failures  Shallow  water  Water  flow  Simulation. Résumé : The Cartesian cut-cell method can be used to represent irregular and complex computational domains with less computational efforts by cutting the grid cells on the boundary surfaces in a background uniform Cartesian mesh. In this study, a modified Cartesian cut-cell grid technique is proposed to better represent complex physical geometries. A point shifting treatment was employed to determine the start and end points of a line segment in cut-cell grids. This led to an improved representation of sharply-shaped corners in surface polygons. Numerical simulation to solve a set of shallow-water equations was performed by incorporating a finite volume approach into the Cartesian cut-cell mesh. The advective fluxes at intercells were first estimated by a Harten, Lax and van Leer for contact wave approximate Riemann solver. In order to improve the model accuracy to the second order, a total variation diminishing-weighted average flux method was applied to work adaptively with the cut-cell mesh. The numerical model was then employed to simulate dam-break flow propagation in a small channel with a rectangular obstacle or a 45° bend. The numerical results show good agreement with available laboratory measurements. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JENMDT&ONLINE=YES&s [...] [article] Numerical simulation of shallow-water flow using a modified cartesian cut-cell approach [texte imprimé] / Hyung-Jun Kim, Auteur ; Lee, Jin Woo, Auteur ; Yong-Sik Cho, Auteur . - pp. 399-404. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 136 N° 3 (Mars 2010) . - pp. 399-404 Mots-clés : Dam  failures  Shallow  water  Water  flow  Simulation. Résumé : The Cartesian cut-cell method can be used to represent irregular and complex computational domains with less computational efforts by cutting the grid cells on the boundary surfaces in a background uniform Cartesian mesh. In this study, a modified Cartesian cut-cell grid technique is proposed to better represent complex physical geometries. A point shifting treatment was employed to determine the start and end points of a line segment in cut-cell grids. This led to an improved representation of sharply-shaped corners in surface polygons. Numerical simulation to solve a set of shallow-water equations was performed by incorporating a finite volume approach into the Cartesian cut-cell mesh. The advective fluxes at intercells were first estimated by a Harten, Lax and van Leer for contact wave approximate Riemann solver. In order to improve the model accuracy to the second order, a total variation diminishing-weighted average flux method was applied to work adaptively with the cut-cell mesh. The numerical model was then employed to simulate dam-break flow propagation in a small channel with a rectangular obstacle or a 45° bend. The numerical results show good agreement with available laboratory measurements. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JENMDT&ONLINE=YES&s [...]

Well-balanced scheme between flux and source terms for computation of shallow-water equations over irregular bathymetry / Dae-Hong Kim in Journal of engineering mechanics, Vol. 134 N°4 (Avril 2008) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 134 N°4 (Avril 2008) . - pp.277–290.. Titre : Well-balanced scheme between flux and source terms for computation of shallow-water equations over irregular bathymetry Type de document : texte imprimé Auteurs : Dae-Hong Kim, Auteur ; Yong-Sik Cho, Auteur ; Hyung-Jun Kim, Auteur Année de publication : 2008 Article en page(s) : pp.277–290.. Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Shallow  waters  Computation  Bathymetry  Numerical  models  Subcritical  flow  Supercritical  flow. Résumé : Although many numerical techniques such as approximate Riemann solvers can be used to analyze subcritical and supercritical flows modeled by hyperbolic-type shallow-water equations, there are some difficulties in practical applications due to the numerical unbalance between source and flux terms. In this study, a revised surface gradient method is proposed that balances source and flux terms. The new numerical model employs the MUSCL–Hancock scheme and the HLLC approximate Riemann solver. Several verifications are conducted, including analyses of transcritical steady-state flows, unsteady dam break flows on a wet and dry bed, and flows over an irregular bathymetry. The model consistently returns accurate and reasonable results comparable to those obtained through analytical methods and laboratory experiments. The revised surface gradient method may be a simple but robust numerical scheme appropriate for solving hyperbolic-type shallow-water equations over an irregular bathymetry. ISSN : 0733-9399 En ligne : http://ascelibrary.org/action/showAbstract?page=277&volume=134&issue=4&journalCo [...] [article] Well-balanced scheme between flux and source terms for computation of shallow-water equations over irregular bathymetry [texte imprimé] / Dae-Hong Kim, Auteur ; Yong-Sik Cho, Auteur ; Hyung-Jun Kim, Auteur . - 2008 . - pp.277–290.. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 134 N°4 (Avril 2008) . - pp.277–290.. Mots-clés : Shallow  waters  Computation  Bathymetry  Numerical  models  Subcritical  flow  Supercritical  flow. Résumé : Although many numerical techniques such as approximate Riemann solvers can be used to analyze subcritical and supercritical flows modeled by hyperbolic-type shallow-water equations, there are some difficulties in practical applications due to the numerical unbalance between source and flux terms. In this study, a revised surface gradient method is proposed that balances source and flux terms. The new numerical model employs the MUSCL–Hancock scheme and the HLLC approximate Riemann solver. Several verifications are conducted, including analyses of transcritical steady-state flows, unsteady dam break flows on a wet and dry bed, and flows over an irregular bathymetry. The model consistently returns accurate and reasonable results comparable to those obtained through analytical methods and laboratory experiments. The revised surface gradient method may be a simple but robust numerical scheme appropriate for solving hyperbolic-type shallow-water equations over an irregular bathymetry. ISSN : 0733-9399 En ligne : http://ascelibrary.org/action/showAbstract?page=277&volume=134&issue=4&journalCo [...]