In this paper, by defining new state vectors and developing new transfer matrices of various elements mov- ing in space, the discrete time transfer matrix method of multi-rigid-flexible-body system is expanded to stud...In this paper, by defining new state vectors and developing new transfer matrices of various elements mov- ing in space, the discrete time transfer matrix method of multi-rigid-flexible-body system is expanded to study the dynamics of multibody system with flexible beams moving in space. Formulations and numerical example of a rigid- flexible-body three pendulums system moving in space are given to validate the method. Using the new method to study the dynamics of multi-rigid-flexible-body system mov- ing in space, the global dynamics equations of system are not needed, the orders of involved matrices of the system are very low and the computational speed is high, irrespec- tive of the size of the system. The new method is simple, straightforward, practical, and provides a powerful tool for multi-rigid-flexible-body system dynamics.展开更多
Using the Control Volume and the Discrete Transfer (DT) methods incorporating the Spectral Band Model, the transient coupled radiative-conductive heat transfer is investigated in cylinders filled with semi-transparent...Using the Control Volume and the Discrete Transfer (DT) methods incorporating the Spectral Band Model, the transient coupled radiative-conductive heat transfer is investigated in cylinders filled with semi-transparent media with both opaque and send-transparent surfaces. This is a three dimensional problem with nonlinear boundary conditions of the second and third kinds. The temperature field in the optical window of a space camera is calculated with complicated boundary conditions. By comparing with the zone and the improved Monte-Carlo methods, the reliability and calculating precision of this method are shown.展开更多
The infrared radiation characteristics of aircraft are a key focus in attack-defense confrontation and early warning detection.A rapid simulation method for calculating the infrared characteristics of targets is propo...The infrared radiation characteristics of aircraft are a key focus in attack-defense confrontation and early warning detection.A rapid simulation method for calculating the infrared characteristics of targets is proposed by combining the discrete transfer method.By constructing the aerodynamic shape of a Su-27-like aircraft,the flow field parameters and skin temperature under cruise conditions were calculated.The proposed method was used to generate infrared images and calculate infrared radiation intensity at various detection angles,and perform speed tests.The results indicate that this method has high accuracy;the generated infrared image is clear,accurate,and can be used to identify the characteristic attributes of the target.In the pitch detection plane,the total infrared radiation intensity of the aircraft exhibits a“8”distribution,with the fuselage contributing the most(approximately 50%).In the yaw plane,the vertical stabilizer’s infrared radiation intensity shows a lobed distribution,with peaks at 60°and 120°.The method can achieve a calculation speed of four times per second for a single detection angle,meeting real-time processing requirements and providing valuable data for infrared target recognition algorithms.展开更多
基金supported by the Natural Science Foundation of China Government (10902051)the Natural Science Foundation of Jiangsu Province (BK2008046)the German Science Foundation
文摘In this paper, by defining new state vectors and developing new transfer matrices of various elements mov- ing in space, the discrete time transfer matrix method of multi-rigid-flexible-body system is expanded to study the dynamics of multibody system with flexible beams moving in space. Formulations and numerical example of a rigid- flexible-body three pendulums system moving in space are given to validate the method. Using the new method to study the dynamics of multi-rigid-flexible-body system mov- ing in space, the global dynamics equations of system are not needed, the orders of involved matrices of the system are very low and the computational speed is high, irrespec- tive of the size of the system. The new method is simple, straightforward, practical, and provides a powerful tool for multi-rigid-flexible-body system dynamics.
文摘Using the Control Volume and the Discrete Transfer (DT) methods incorporating the Spectral Band Model, the transient coupled radiative-conductive heat transfer is investigated in cylinders filled with semi-transparent media with both opaque and send-transparent surfaces. This is a three dimensional problem with nonlinear boundary conditions of the second and third kinds. The temperature field in the optical window of a space camera is calculated with complicated boundary conditions. By comparing with the zone and the improved Monte-Carlo methods, the reliability and calculating precision of this method are shown.
基金This work was supported by the National Natural Science Foundation of China(12102356).
文摘The infrared radiation characteristics of aircraft are a key focus in attack-defense confrontation and early warning detection.A rapid simulation method for calculating the infrared characteristics of targets is proposed by combining the discrete transfer method.By constructing the aerodynamic shape of a Su-27-like aircraft,the flow field parameters and skin temperature under cruise conditions were calculated.The proposed method was used to generate infrared images and calculate infrared radiation intensity at various detection angles,and perform speed tests.The results indicate that this method has high accuracy;the generated infrared image is clear,accurate,and can be used to identify the characteristic attributes of the target.In the pitch detection plane,the total infrared radiation intensity of the aircraft exhibits a“8”distribution,with the fuselage contributing the most(approximately 50%).In the yaw plane,the vertical stabilizer’s infrared radiation intensity shows a lobed distribution,with peaks at 60°and 120°.The method can achieve a calculation speed of four times per second for a single detection angle,meeting real-time processing requirements and providing valuable data for infrared target recognition algorithms.
