Based on the atmospheric dynamics, a two dimensional, slab symmetric numerical microburst model is developed. The model subdivides water substance into five types, including water vapor, cloud droplets, rainwater, i...Based on the atmospheric dynamics, a two dimensional, slab symmetric numerical microburst model is developed. The model subdivides water substance into five types, including water vapor, cloud droplets, rainwater, ice crystals and graupels (hails), considering the detailed microphysical processes of warm cloud and ice phase as well. By the model the wet microburst is numerically simulated with an agreeable result. In addition, ten experiments are conducted in order to examine the microburst sensitivity to environmental conditions.展开更多
This article deals with real-time hi-fi simulation of large aircraft flying in turbulent wind in a simulator to study its takeoff and landing behavior in microburst wind shear. A parameterized three-dimensional （3D）...This article deals with real-time hi-fi simulation of large aircraft flying in turbulent wind in a simulator to study its takeoff and landing behavior in microburst wind shear. A parameterized three-dimensional （3D） microburst model is built up on the basis of vortex ring and Rankine vortex principle. Complicated microburst wind fields are simulated by means of vortex ring declination and multi-vortex superposition. Based on the modeling data of Boeing 747-100, a dynamic model with wind shear effects considered is established and a general method to modify the aerodynamic model is proposed. A controller for longitudinal and lateral escapes is designed and verified in simulated microburst wind field. Results indicate that, with high extensibility, reasonability and effectiveness, the 3D microburst model with wind shear effects considered is fit to simulate real wind fields. Different escape schemes can be adopted to fly through a wind field from different locations. The model can be used for real-time flight simulation in a flight simulator.展开更多
Microburst is a special kind of low-level wind shear, which may do great damage to aircrafts. Modelling of a microburst is significant for flight simulations. In this paper we adopt multiple vortex ring principle to m...Microburst is a special kind of low-level wind shear, which may do great damage to aircrafts. Modelling of a microburst is significant for flight simulations. In this paper we adopt multiple vortex ring principle to model microburst and propose a new parameter selection method of multiple vortex ring model. We treat the parameters selection as an optimization problem, and introduce the differential evolution algorithm into it. A nested differential evolution algorithm is proposed to complete the two optimization process, objective optimization and intermediate optimization. The simulation results show that this method can flexibly generate microburst with any maximum wind velocity.展开更多
An engineering microburst model to generate the microburst wind field for virtual flight simulation has been presented. The model is built as a finite viscosity vortex core model based on the vortex ring theory consid...An engineering microburst model to generate the microburst wind field for virtual flight simulation has been presented. The model is built as a finite viscosity vortex core model based on the vortex ring theory considering the air viscosity,and it can solve the problem of induced velocity discontinuity at the inner region near the vortex core. Moreover,the central axis velocity is obtained by turbulence free jet theory so as to avoid the singularity.The parameters in multiple-vortex-ring microburst model are determined by improved quantum genetic algorithm( QGA) based on immune and mutation operator,and the parameters optimization of the model under condition of different maximum vertical velocity are investigated. The results show that the microburst model is effective and accurate. The simulation results fit the preset value very well,and the error is controlled within 10^(- 7).展开更多
Based on observational analyses and on-site ground and aerial damage surveys, this work aims to reveal the weather phenomena--especially the wind situation--when Oriental Star capsized in the Yangtze River on June 1, ...Based on observational analyses and on-site ground and aerial damage surveys, this work aims to reveal the weather phenomena--especially the wind situation--when Oriental Star capsized in the Yangtze River on June 1, 2015. Results demonstrate that the cruise ship capsized when it encountered strong winds at speeds of at least 31 m s ^-1 near the apex of a bow echo embedded in a squall line. As suggested by the fallen trees within a 2-kin radius around the wreck location, such strong winds were likely caused by microburst straight-line wind and/or embedded small vortices, rather than tomadoes.展开更多
文摘Based on the atmospheric dynamics, a two dimensional, slab symmetric numerical microburst model is developed. The model subdivides water substance into five types, including water vapor, cloud droplets, rainwater, ice crystals and graupels (hails), considering the detailed microphysical processes of warm cloud and ice phase as well. By the model the wet microburst is numerically simulated with an agreeable result. In addition, ten experiments are conducted in order to examine the microburst sensitivity to environmental conditions.
基金Foundation item： Program of National Natural Science Foundation of China and The Civil Aviation （60776812）
文摘This article deals with real-time hi-fi simulation of large aircraft flying in turbulent wind in a simulator to study its takeoff and landing behavior in microburst wind shear. A parameterized three-dimensional （3D） microburst model is built up on the basis of vortex ring and Rankine vortex principle. Complicated microburst wind fields are simulated by means of vortex ring declination and multi-vortex superposition. Based on the modeling data of Boeing 747-100, a dynamic model with wind shear effects considered is established and a general method to modify the aerodynamic model is proposed. A controller for longitudinal and lateral escapes is designed and verified in simulated microburst wind field. Results indicate that, with high extensibility, reasonability and effectiveness, the 3D microburst model with wind shear effects considered is fit to simulate real wind fields. Different escape schemes can be adopted to fly through a wind field from different locations. The model can be used for real-time flight simulation in a flight simulator.
基金Sponsored by the National Natural Science Foundation of China(Grant No. 61201305)the Heilongjiang Provincial Postdoctoral Foundation(Grant No.LBH-Z11170)the Fundamental Research Funds for the Central Universities(Grant No. HIT. NSRIF. 2012015)
文摘Microburst is a special kind of low-level wind shear, which may do great damage to aircrafts. Modelling of a microburst is significant for flight simulations. In this paper we adopt multiple vortex ring principle to model microburst and propose a new parameter selection method of multiple vortex ring model. We treat the parameters selection as an optimization problem, and introduce the differential evolution algorithm into it. A nested differential evolution algorithm is proposed to complete the two optimization process, objective optimization and intermediate optimization. The simulation results show that this method can flexibly generate microburst with any maximum wind velocity.
基金National Natural Science Foundation of China(No.61032001)
文摘An engineering microburst model to generate the microburst wind field for virtual flight simulation has been presented. The model is built as a finite viscosity vortex core model based on the vortex ring theory considering the air viscosity,and it can solve the problem of induced velocity discontinuity at the inner region near the vortex core. Moreover,the central axis velocity is obtained by turbulence free jet theory so as to avoid the singularity.The parameters in multiple-vortex-ring microburst model are determined by improved quantum genetic algorithm( QGA) based on immune and mutation operator,and the parameters optimization of the model under condition of different maximum vertical velocity are investigated. The results show that the microburst model is effective and accurate. The simulation results fit the preset value very well,and the error is controlled within 10^(- 7).
基金the Ministry of Science and Technology of China (2013CB430104)he National Natural Science Foundation of China (41425018, 4141101075, and 41375048)
文摘Based on observational analyses and on-site ground and aerial damage surveys, this work aims to reveal the weather phenomena--especially the wind situation--when Oriental Star capsized in the Yangtze River on June 1, 2015. Results demonstrate that the cruise ship capsized when it encountered strong winds at speeds of at least 31 m s ^-1 near the apex of a bow echo embedded in a squall line. As suggested by the fallen trees within a 2-kin radius around the wreck location, such strong winds were likely caused by microburst straight-line wind and/or embedded small vortices, rather than tomadoes.
