With the purpose of making calculation more efficient in practical hydraulic simulations, an improved algorithm was proposed and was applied in the practical water distribution field. This methodology was developed by...With the purpose of making calculation more efficient in practical hydraulic simulations, an improved algorithm was proposed and was applied in the practical water distribution field. This methodology was developed by expanding the traditional loop-equation theory through utilization of the advantages of the graph theory in efficiency. The utilization of the spanning tree technique from graph theory makes the proposed algorithm efficient in calculation and simple to use for computer coding. The algorithms for topological generation and practical implementations are presented in detail in this paper. Through the application to a practical urban system, the consumption of the CPU time and computation memory were decreased while the accuracy was greatly enhanced compared with the present existing methods.展开更多
A large eddy simulation(LES)is conducted to investigate the distribution of turbulence kinetic energy(TKE)under a plunging solitary wave over a 1:15 slope.This study provides a novel contribution to the field by exami...A large eddy simulation(LES)is conducted to investigate the distribution of turbulence kinetic energy(TKE)under a plunging solitary wave over a 1:15 slope.This study provides a novel contribution to the field by examining the roles of resolved and sub-grid scale TKE in plunging solitary waves at the different stages of wave breaking.Furthermore,comparing the performances of two sub-grid scale(SGS)models in simulating the distribution of TKE was carried out to identify their performances.The separate investigation of these components in the context of wave breaking and recognizing the importance of an appropriate sub-grid scale model to consider the effects of small-scale eddies provide a significant advancement in understanding coastal morphological changes and nearshore sediment transport.Both the zero-equation and one-equation SGS models demonstrated acceptable performance in simulating water surface and kinematic properties.The one-equation SGS model,however,provided more accurate results on TKE transport during the breaking process and as the wave approaches its collapsing point.The study’s results reveal that an SGS model’s inability to simulate TKE transport(such as in the zero equation model)leads to inaccurate simulations of the TKE level and breaking location in the breaking zone.Additionally,the results of the one-equation model demonstrated that the maximum horizontal fluid velocity around the wavefront surface is a better predictor of breaking wave onset than the horizontal fluid velocity at the wave crest.展开更多
基金funded by the National Natural Science Foundation of China(51922096)the Excellent Youth Natural Science Foundation of Zhejiang Province,China(LR19E080003)the support from the Hong Kong Research Grants Council(RGC)(15200719)。
文摘With the purpose of making calculation more efficient in practical hydraulic simulations, an improved algorithm was proposed and was applied in the practical water distribution field. This methodology was developed by expanding the traditional loop-equation theory through utilization of the advantages of the graph theory in efficiency. The utilization of the spanning tree technique from graph theory makes the proposed algorithm efficient in calculation and simple to use for computer coding. The algorithms for topological generation and practical implementations are presented in detail in this paper. Through the application to a practical urban system, the consumption of the CPU time and computation memory were decreased while the accuracy was greatly enhanced compared with the present existing methods.
基金funding support from the Research Institute for Sustainable Urban Development at the Hong Kong Polytechnic University(project numbers 1-BD86 and 1-BBWT).
文摘A large eddy simulation(LES)is conducted to investigate the distribution of turbulence kinetic energy(TKE)under a plunging solitary wave over a 1:15 slope.This study provides a novel contribution to the field by examining the roles of resolved and sub-grid scale TKE in plunging solitary waves at the different stages of wave breaking.Furthermore,comparing the performances of two sub-grid scale(SGS)models in simulating the distribution of TKE was carried out to identify their performances.The separate investigation of these components in the context of wave breaking and recognizing the importance of an appropriate sub-grid scale model to consider the effects of small-scale eddies provide a significant advancement in understanding coastal morphological changes and nearshore sediment transport.Both the zero-equation and one-equation SGS models demonstrated acceptable performance in simulating water surface and kinematic properties.The one-equation SGS model,however,provided more accurate results on TKE transport during the breaking process and as the wave approaches its collapsing point.The study’s results reveal that an SGS model’s inability to simulate TKE transport(such as in the zero equation model)leads to inaccurate simulations of the TKE level and breaking location in the breaking zone.Additionally,the results of the one-equation model demonstrated that the maximum horizontal fluid velocity around the wavefront surface is a better predictor of breaking wave onset than the horizontal fluid velocity at the wave crest.
