Urban flooding poses serious threats to human life. In China, many cities have recently experienced flooding during every rainy season. Several years ago, policies, scientific methods, and engineering measures were ap...Urban flooding poses serious threats to human life. In China, many cities have recently experienced flooding during every rainy season. Several years ago, policies, scientific methods, and engineering measures were applied to address this systematic problem. However, flooding disasters remain frequent in urban areas in China. Therefore, this article discusses the human-earth relationship from a philosophical perspective to analyse the causes of urban water problems. This article mainly illustrates the value of the what-if analysis concept and how to use this concept to address urban flooding issues and improve the management of urban overland flow. However, the existing simulation models and software do not effectively support what-if analyses. In particular, most existing urban hydrological simulation models and software do not sufficiently consider the heterogeneity of geographical objects on urban surfaces and lack interactions to support what-if analyses. These limitations hinder effective implementation of what-if analysis. This article introduces three key technologies that allow an urban overland flow simulation system to effectively support what-if analyses: 1) urban spatial automatic discretization and topo-adjacency, which reflect the heterogeneity of an urban area;2) hydrological models for the simulation of the hydrologicalprocesses of the main geographical objects in the urban area;and 3) key strategies for a visual analytic platform to support what-if analyses in well-perceived way. The experiment was conducted using a community in Chongqing as a case study. The results demonstrate that the designed key technologies and functions of the proposed system can support what-if analysis and that what-if analysis is an important and useful concept for urban water management.展开更多
In this paper, a compact finite difference method is presented for solving the initial boundary value problems for the improved Boussinesq equation with damping terms. The fourth-order equation can be transformed into...In this paper, a compact finite difference method is presented for solving the initial boundary value problems for the improved Boussinesq equation with damping terms. The fourth-order equation can be transformed into a first-order ordinary differential system, and then, the classical Pad4 approximation is used to discretize spatial derivative in the non- linear partial differential equations. The resulting coefficient matrix for the semi-discrete scheme is tri-diagonal and can be solved efficiently. In order to maintain the same order of convergence, the classical fourth-order Runge-Kutta method is the preferred method for explicit time integration. Soliton-type solutions are used to evaluate the accuracy of the method, and various numerical experiments are designed to test the different effects of the damping terms.展开更多
文摘Urban flooding poses serious threats to human life. In China, many cities have recently experienced flooding during every rainy season. Several years ago, policies, scientific methods, and engineering measures were applied to address this systematic problem. However, flooding disasters remain frequent in urban areas in China. Therefore, this article discusses the human-earth relationship from a philosophical perspective to analyse the causes of urban water problems. This article mainly illustrates the value of the what-if analysis concept and how to use this concept to address urban flooding issues and improve the management of urban overland flow. However, the existing simulation models and software do not effectively support what-if analyses. In particular, most existing urban hydrological simulation models and software do not sufficiently consider the heterogeneity of geographical objects on urban surfaces and lack interactions to support what-if analyses. These limitations hinder effective implementation of what-if analysis. This article introduces three key technologies that allow an urban overland flow simulation system to effectively support what-if analyses: 1) urban spatial automatic discretization and topo-adjacency, which reflect the heterogeneity of an urban area;2) hydrological models for the simulation of the hydrologicalprocesses of the main geographical objects in the urban area;and 3) key strategies for a visual analytic platform to support what-if analyses in well-perceived way. The experiment was conducted using a community in Chongqing as a case study. The results demonstrate that the designed key technologies and functions of the proposed system can support what-if analysis and that what-if analysis is an important and useful concept for urban water management.
文摘In this paper, a compact finite difference method is presented for solving the initial boundary value problems for the improved Boussinesq equation with damping terms. The fourth-order equation can be transformed into a first-order ordinary differential system, and then, the classical Pad4 approximation is used to discretize spatial derivative in the non- linear partial differential equations. The resulting coefficient matrix for the semi-discrete scheme is tri-diagonal and can be solved efficiently. In order to maintain the same order of convergence, the classical fourth-order Runge-Kutta method is the preferred method for explicit time integration. Soliton-type solutions are used to evaluate the accuracy of the method, and various numerical experiments are designed to test the different effects of the damping terms.
