The stratospheric quasi-zero wind layer (QZWL) is a transition region with low zonal wind speeds in the lower stratosphere at an altitude of ~20 km. The zonal wind direction above the QZWL layer is opposite to that be...The stratospheric quasi-zero wind layer (QZWL) is a transition region with low zonal wind speeds in the lower stratosphere at an altitude of ~20 km. The zonal wind direction above the QZWL layer is opposite to that below the QZWL layer and the north –south wind component is small. The atmospheric wind field near the stratospheric QZWL is an important factor affecting the flight altitude and dynamic control of stratospheric airships. It is therefore necessary to study the stratospheric QZWL to provide better environmental information for these aircraft. High-resolution radiosonde data were used to analyze the characteristics of the stratospheric QZWL over Korla, Xinjiang Province, China. A weak wind layer in which the wind direction suddenly reversed from westerly to easterly was observed at ~20 km in the lower stratosphere, characteristic of the stratospheric QZWL. The Weather Research and Forecasting model was used to simulate the profiles of the horizontal wind speed and direction over Korla. The forcing effect of each diagnostic term in the equation on the zonal wind speed was analyzed. The results showed that the advection term was the dominant factor forcing the zonal wind speed. The wave term had a secondary forcing role, although the forcing effect of the wave term on the zonal wind speed was significant in some regions.展开更多
The parametric model of stratospheric airships is established in the body axes coordinate system. In this paper we study the turning mechanism of stratospheric airships including the generated forces and the key param...The parametric model of stratospheric airships is established in the body axes coordinate system. In this paper we study the turning mechanism of stratospheric airships including the generated forces and the key parameters for steady turning. We compare and analyze the different driven-characteristics between aerodynamic control surfaces and vectored thrust in turning. We design a composite control combining aerodynamic control surfaces and vectored thrust according to different dynamic pressure conditions, to achieve coordinated turning under high or low airspeed situations.展开更多
The advance of transportation technology depends on science and economics. During the 1930s, airships and airplanes competed head-to-head for the Atlantic passenger market. When World War 2 broke out, everything chang...The advance of transportation technology depends on science and economics. During the 1930s, airships and airplanes competed head-to-head for the Atlantic passenger market. When World War 2 broke out, everything changed. Over the next five years, the combined combatants built over half of a million military airplanes. By the end of the war, four-engine, high-altitude bombers and jet engines were developed. Further investment in airplane technology was stimulated by the Cold War. All this public investment was adapted to civilian passenger jet airplanes. By 1980, dedicated jet airplanes were in use as cargo carriers. Despite the growth of the cargojet market over the past three decades, rising fuel costs and environmental concerns are changing the economics of airships and airplanes again. Investment in large cargo airships is returning. Much of the technology developed for fixed-wing aircraft can be applied to cargo airships. New materials, better engines, control systems and engineering eliminate the need for large ground crews and improve airship reliability and safety. However, two fundamental design issues have yet to be resolved: structural integrity and buoyancy control. A worldwide competition is underway on three continents to develop the dominant design for a cargo airship. This paper examines the alternative design approaches and presents the status of the international competition.展开更多
Fluid-structure interaction is an important issue for non-rigid airships with inflated envelopes. In this study, a wind tunnel test is conducted, and a loosely coupled procedure is correspondingly established for nume...Fluid-structure interaction is an important issue for non-rigid airships with inflated envelopes. In this study, a wind tunnel test is conducted, and a loosely coupled procedure is correspondingly established for numerical simulation based on computational fluid dynamics and nonlinear finite element analysis methods. The typical results of the numerical simulation and wind tunnel experiment, including the overall lift and deformation, are in good agreement with each other. The results obtained indicate that the effect of fluid-structure interaction is noticeable and should be considered for non-rigid airships. Flow- induced deformation can further intensify the upward lift force and pitching moment, which can lead to a large deformation. Under a wind speed of 15 m/s, the lift force of the non-rigid model is increased to approximatelv 60% compared with that of the rigid model under a high angle of attack.展开更多
基金supported by National Outstanding Youth Science Foundation(61125306)National Natural Science Foundation of Major Research Plan(91016004,61034002)+2 种基金Specialized Research Fund for the Doctoral Program of Higher Education of China(20110092110020)Open Fund of Key Laboratory of Measurement and Control of Complex Systems of Engineering(Southeast University)Ministry of Education(MCCSE2013B01)
基金supported by National Natural Science Foundation of China(61425008,61333004,61273054)Top-Notch Young Talents Program of China,and Aeronautical Foundation of China(2013585104)
基金supported by National Natural Science Foundation of China(61125306,61273092,61301035,61304018,and 61411130160)National HighTechnology Research and Development Program of China(2014AA051901)+4 种基金Tianjin Science and Technology Supporting Program(14JCQNJC05400)Research Innovation Program of Tianjin University(2013XQ0101)Hubei Science and Technology Supporting Program(XYJ2014000314)Science Foundation of China Supported by Science and Technology on Aircraft Control Laboratory(20125848004)China Post-doctoral Science Foundation(2014M561559)
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA17010105)
文摘The stratospheric quasi-zero wind layer (QZWL) is a transition region with low zonal wind speeds in the lower stratosphere at an altitude of ~20 km. The zonal wind direction above the QZWL layer is opposite to that below the QZWL layer and the north –south wind component is small. The atmospheric wind field near the stratospheric QZWL is an important factor affecting the flight altitude and dynamic control of stratospheric airships. It is therefore necessary to study the stratospheric QZWL to provide better environmental information for these aircraft. High-resolution radiosonde data were used to analyze the characteristics of the stratospheric QZWL over Korla, Xinjiang Province, China. A weak wind layer in which the wind direction suddenly reversed from westerly to easterly was observed at ~20 km in the lower stratosphere, characteristic of the stratospheric QZWL. The Weather Research and Forecasting model was used to simulate the profiles of the horizontal wind speed and direction over Korla. The forcing effect of each diagnostic term in the equation on the zonal wind speed was analyzed. The results showed that the advection term was the dominant factor forcing the zonal wind speed. The wave term had a secondary forcing role, although the forcing effect of the wave term on the zonal wind speed was significant in some regions.
基金Project (No.61175074) supported by the National Natural Science Foundation of China
文摘The parametric model of stratospheric airships is established in the body axes coordinate system. In this paper we study the turning mechanism of stratospheric airships including the generated forces and the key parameters for steady turning. We compare and analyze the different driven-characteristics between aerodynamic control surfaces and vectored thrust in turning. We design a composite control combining aerodynamic control surfaces and vectored thrust according to different dynamic pressure conditions, to achieve coordinated turning under high or low airspeed situations.
基金supported by National Natural Science Foundation of China(61174102)Jiangsu Natural Science Foundation of China(SBK20130033)+1 种基金Aeronautical Science Foundation of China 20145152029)Specialized Research Fund for the Doctoral Program of Higher Education(20133218110013)
文摘The advance of transportation technology depends on science and economics. During the 1930s, airships and airplanes competed head-to-head for the Atlantic passenger market. When World War 2 broke out, everything changed. Over the next five years, the combined combatants built over half of a million military airplanes. By the end of the war, four-engine, high-altitude bombers and jet engines were developed. Further investment in airplane technology was stimulated by the Cold War. All this public investment was adapted to civilian passenger jet airplanes. By 1980, dedicated jet airplanes were in use as cargo carriers. Despite the growth of the cargojet market over the past three decades, rising fuel costs and environmental concerns are changing the economics of airships and airplanes again. Investment in large cargo airships is returning. Much of the technology developed for fixed-wing aircraft can be applied to cargo airships. New materials, better engines, control systems and engineering eliminate the need for large ground crews and improve airship reliability and safety. However, two fundamental design issues have yet to be resolved: structural integrity and buoyancy control. A worldwide competition is underway on three continents to develop the dominant design for a cargo airship. This paper examines the alternative design approaches and presents the status of the international competition.
基金the National Natural Science Foundation of China (11202215 and 11332011)the Youth Innovation Promotion Association of CAS (2015015)
文摘Fluid-structure interaction is an important issue for non-rigid airships with inflated envelopes. In this study, a wind tunnel test is conducted, and a loosely coupled procedure is correspondingly established for numerical simulation based on computational fluid dynamics and nonlinear finite element analysis methods. The typical results of the numerical simulation and wind tunnel experiment, including the overall lift and deformation, are in good agreement with each other. The results obtained indicate that the effect of fluid-structure interaction is noticeable and should be considered for non-rigid airships. Flow- induced deformation can further intensify the upward lift force and pitching moment, which can lead to a large deformation. Under a wind speed of 15 m/s, the lift force of the non-rigid model is increased to approximatelv 60% compared with that of the rigid model under a high angle of attack.
