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
This paper generalizes the contour dynamics for single ring vortices to that for multiple ring vortices,wherein sixsets of numerical computation are performed.The phenomenon of the counterclockwise loop of a moving vo...This paper generalizes the contour dynamics for single ring vortices to that for multiple ring vortices,wherein sixsets of numerical computation are performed.The phenomenon of the counterclockwise loop of a moving vortex is clearly shown in the computational results and the asymmetric change with time of the vortex structure may serve as a pre-cursor for the phenomenon.Besides,we also discuss the dependence of the motion direction of a vortex upon the degreeof its contour denseness,and the dependence of the westward component of vortex motion upon its asymmetricstructure.The results are fairly consistent with those of previous dynamical analyses and numerical experiments.展开更多
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This work is supported by the National Natural Science Foundation of China.
文摘This paper generalizes the contour dynamics for single ring vortices to that for multiple ring vortices,wherein sixsets of numerical computation are performed.The phenomenon of the counterclockwise loop of a moving vortex is clearly shown in the computational results and the asymmetric change with time of the vortex structure may serve as a pre-cursor for the phenomenon.Besides,we also discuss the dependence of the motion direction of a vortex upon the degreeof its contour denseness,and the dependence of the westward component of vortex motion upon its asymmetricstructure.The results are fairly consistent with those of previous dynamical analyses and numerical experiments.
