The large eddy simulation(LES)method combined with the global dynamic grid strategy is used to numerically study the influence of pitch angles on cavitation and ventilation phenomena in the rear of fuselage during dit...The large eddy simulation(LES)method combined with the global dynamic grid strategy is used to numerically study the influence of pitch angles on cavitation and ventilation phenomena in the rear of fuselage during ditching.The volume of fluid(VOF)method is used to capture the interface.By analyzing the normal force,moment,pressure distribution and nephograms,we find that the pitch angle has a great influence on the total load,the cavitation occurrence time and its transition to ventilation,thus affects the longitudinal load distribution and the controlling of aircraft dynamics.展开更多
Dynamic latency over the Intemet is an Important parameter for evaluating the performance of Web service orchestration. In this paper, we propose a performance analyzing and correctness checking method for service orc...Dynamic latency over the Intemet is an Important parameter for evaluating the performance of Web service orchestration. In this paper, we propose a performance analyzing and correctness checking method for service orchestration with dynamic latency simulated in Colored PetriNets （CPNs）. First, we extend the CPN to Web Service Composition Orchestration Network System （WS-CONS） for the description of dynamic latency in service orchestration. Secondly, with simulated dynamic latency, a buffer-limited policy and admittance-control policy are designed in WS- CONS and implemented on CPN Tools. In the buffer-limited policy, the passing messages would be discarded if the node capacity is not adequate. In the admittance-control policy, the ability of a message entering the system depends on the number of messages concurrently flowing in the system. This helps to enhance the success rate of message passing. Finally, the system performance is evaluated through running models in CPN Tools. Simulated results show that the dynamic latency plays an important role in the system throughput and response latency. This simulation helps system designers to quickly make proper compromises at low cost.展开更多
文摘The large eddy simulation(LES)method combined with the global dynamic grid strategy is used to numerically study the influence of pitch angles on cavitation and ventilation phenomena in the rear of fuselage during ditching.The volume of fluid(VOF)method is used to capture the interface.By analyzing the normal force,moment,pressure distribution and nephograms,we find that the pitch angle has a great influence on the total load,the cavitation occurrence time and its transition to ventilation,thus affects the longitudinal load distribution and the controlling of aircraft dynamics.
基金This paper was supported by the National Natural Science Foundation of China under Grants No.61170053,No.61101214,No.61100205，the National High-Tech Research and Development Plan of China under Grant No.2012AA010902-1，the Natural Science Foundation of Beijing under Grant No.4112027，Special Project of National CAS Union-The High Performace Cloud Service Platform for Enterprise Creative Computing
文摘Dynamic latency over the Intemet is an Important parameter for evaluating the performance of Web service orchestration. In this paper, we propose a performance analyzing and correctness checking method for service orchestration with dynamic latency simulated in Colored PetriNets （CPNs）. First, we extend the CPN to Web Service Composition Orchestration Network System （WS-CONS） for the description of dynamic latency in service orchestration. Secondly, with simulated dynamic latency, a buffer-limited policy and admittance-control policy are designed in WS- CONS and implemented on CPN Tools. In the buffer-limited policy, the passing messages would be discarded if the node capacity is not adequate. In the admittance-control policy, the ability of a message entering the system depends on the number of messages concurrently flowing in the system. This helps to enhance the success rate of message passing. Finally, the system performance is evaluated through running models in CPN Tools. Simulated results show that the dynamic latency plays an important role in the system throughput and response latency. This simulation helps system designers to quickly make proper compromises at low cost.
