Shipboard operations as a hazardous process require the human element to be aware of any operation risks. Since the concept of human error exposed to ample arguments, the introduction of human element concerns to prac...Shipboard operations as a hazardous process require the human element to be aware of any operation risks. Since the concept of human error exposed to ample arguments, the introduction of human element concerns to practices rather than other means is essential because the provenance of accidents is human error. HRA （human reliability assessment） is a theoretical framework to assess the human actions for predicting the potential human error probability of a certain given task or operation scenario. Furthermore, surveillance of the human performance is through the task by steps and sub-steps. The CREAM （cognitive reliability and error analysis method） tool is the second generation of HRA which emphasizes the features of the context and utilized as retrospective and prospective tool. The paper illustrates the basic and extended version of CREAM and its suitability for critical shipboard operations safety assessment.展开更多
A discontinuous Galerkin method based on an artificial viscosity model is investigated in the context of the simulation of compressible turbulence. The effects of artificial viscosity on shock capturing ability, broad...A discontinuous Galerkin method based on an artificial viscosity model is investigated in the context of the simulation of compressible turbulence. The effects of artificial viscosity on shock capturing ability, broadband accuracy and under-resolved instability are examined combined with various orders and mesh resolutions. For shock-dominated flows, the superior accuracy of high order methods in terms of discontinuity resolution are well retained compared with lower ones. For under-resolved simulations, the artificial viscosity model is able to enhance stability of the eighth order discontinuous Galerkin method despite of detrimental influence for accuracy. For multi-scale flows, the artificial viscosity model demonstrates biased numerical dissipation towards higher wavenumbers. Capability in terms of boundary layer flows and hybrid meshes is also demonstrated.It is concluded that the fourth order artificial viscosity discontinuous Galerkin method is comparable to typical high order finite difference methods in the literature in terms of accuracy for identical number of degrees of freedom, while the eighth order is significantly better unless the under-resolved instability issue is raised. Furthermore, the artificial viscosity discontinuous Galerkin method is shown to provide appropriate numerical dissipation as compensation for turbulent kinetic energy decaying on moderately coarse meshes, indicating good potentiality for implicit large eddy simulation.展开更多
文摘Shipboard operations as a hazardous process require the human element to be aware of any operation risks. Since the concept of human error exposed to ample arguments, the introduction of human element concerns to practices rather than other means is essential because the provenance of accidents is human error. HRA （human reliability assessment） is a theoretical framework to assess the human actions for predicting the potential human error probability of a certain given task or operation scenario. Furthermore, surveillance of the human performance is through the task by steps and sub-steps. The CREAM （cognitive reliability and error analysis method） tool is the second generation of HRA which emphasizes the features of the context and utilized as retrospective and prospective tool. The paper illustrates the basic and extended version of CREAM and its suitability for critical shipboard operations safety assessment.
基金supported by the National Natural Science Foundation of China(Grant No.11402016)the Fundamental Research Funds for the Central Universities(Grant Nos.50100002014105020&50100002015105033)
文摘A discontinuous Galerkin method based on an artificial viscosity model is investigated in the context of the simulation of compressible turbulence. The effects of artificial viscosity on shock capturing ability, broadband accuracy and under-resolved instability are examined combined with various orders and mesh resolutions. For shock-dominated flows, the superior accuracy of high order methods in terms of discontinuity resolution are well retained compared with lower ones. For under-resolved simulations, the artificial viscosity model is able to enhance stability of the eighth order discontinuous Galerkin method despite of detrimental influence for accuracy. For multi-scale flows, the artificial viscosity model demonstrates biased numerical dissipation towards higher wavenumbers. Capability in terms of boundary layer flows and hybrid meshes is also demonstrated.It is concluded that the fourth order artificial viscosity discontinuous Galerkin method is comparable to typical high order finite difference methods in the literature in terms of accuracy for identical number of degrees of freedom, while the eighth order is significantly better unless the under-resolved instability issue is raised. Furthermore, the artificial viscosity discontinuous Galerkin method is shown to provide appropriate numerical dissipation as compensation for turbulent kinetic energy decaying on moderately coarse meshes, indicating good potentiality for implicit large eddy simulation.
