Tephra fallout is an important type of hazard caused by explosive volcanic eruption, and numerical simulation has become a fast and effective approach to assess the dispersion and deposition of tephra fallout. Accordi...Tephra fallout is an important type of hazard caused by explosive volcanic eruption, and numerical simulation has become a fast and effective approach to assess the dispersion and deposition of tephra fallout. According to the improved 2D diffusion model of Suzuki （ 1983）, we edited a tephra diffusion program that can run in the Windows system. Based on previous data, we simulated the diffusion scope of the Jinlongdingzi volcanic eruption, which is the latest eruption in the Longgang volcanic cluster. The simulated results are in good agreement with the results from measurement in situ, indicating that the model is reliable and the parameters used in the model are suitable. By using wind profiles of ten years, 7, 021 simulations under different wind profiles were carried out, and then probabilistic hazard maps of tephra fallout were constructed for tephra thickness thresholds, lcm and 0.5cm. This study can provide an important scientific basis for volcanic hazard analysis, risk mitigation plans and countermeasures in the Longgang volcanic area.展开更多
Uncontained Engine Rotor Failure(UERF)can cause a catastrophic failure of an aircraft,and the quantitative assessment of the hazards related to UERF is a very important part of safety analysis.However,the procedure fo...Uncontained Engine Rotor Failure(UERF)can cause a catastrophic failure of an aircraft,and the quantitative assessment of the hazards related to UERF is a very important part of safety analysis.However,the procedure for hazard quantification of UERF recommended by the Federal Aviation Administration in advisory circular AC20-128A is cumbersome,as it involves building auxiliary lines and curve projections.To improve the efficiency and general applicability of the risk angle calculation,a boundary discretization method is developed that involves discretizing the geometry of the target part/structure into node points and calculating the risk angles numerically by iterating a particular algorithm over each node point.The improved efficiency and excellent accuracy for the developed algorithm was validated through a comparison with manual solutions for the hazard quantification of the engine nacelle structures of a passenger aircraft using the guidance in AC20-128A.To further demonstrate the applicability of the boundary discretization method,the proposed algorithm was used to examine the influence of the target size and the distance between the target and rotor on the hazard probability.展开更多
基金unded by the National Natural Science Foundation Project(40972209)the Special Projects for China Earthquake Research(201208005)
文摘Tephra fallout is an important type of hazard caused by explosive volcanic eruption, and numerical simulation has become a fast and effective approach to assess the dispersion and deposition of tephra fallout. According to the improved 2D diffusion model of Suzuki （ 1983）, we edited a tephra diffusion program that can run in the Windows system. Based on previous data, we simulated the diffusion scope of the Jinlongdingzi volcanic eruption, which is the latest eruption in the Longgang volcanic cluster. The simulated results are in good agreement with the results from measurement in situ, indicating that the model is reliable and the parameters used in the model are suitable. By using wind profiles of ten years, 7, 021 simulations under different wind profiles were carried out, and then probabilistic hazard maps of tephra fallout were constructed for tephra thickness thresholds, lcm and 0.5cm. This study can provide an important scientific basis for volcanic hazard analysis, risk mitigation plans and countermeasures in the Longgang volcanic area.
基金supported by the National Natural Science Foundation of China(No.51706187)。
文摘Uncontained Engine Rotor Failure(UERF)can cause a catastrophic failure of an aircraft,and the quantitative assessment of the hazards related to UERF is a very important part of safety analysis.However,the procedure for hazard quantification of UERF recommended by the Federal Aviation Administration in advisory circular AC20-128A is cumbersome,as it involves building auxiliary lines and curve projections.To improve the efficiency and general applicability of the risk angle calculation,a boundary discretization method is developed that involves discretizing the geometry of the target part/structure into node points and calculating the risk angles numerically by iterating a particular algorithm over each node point.The improved efficiency and excellent accuracy for the developed algorithm was validated through a comparison with manual solutions for the hazard quantification of the engine nacelle structures of a passenger aircraft using the guidance in AC20-128A.To further demonstrate the applicability of the boundary discretization method,the proposed algorithm was used to examine the influence of the target size and the distance between the target and rotor on the hazard probability.
