An analytical study was presented on active control of sound transmission into a vibro-acoustic enclosure comprising two flexible plates. Two types of actuators were used, i.e. acoustic actuator and distributed lead z...An analytical study was presented on active control of sound transmission into a vibro-acoustic enclosure comprising two flexible plates. Two types of actuators were used, i.e. acoustic actuator and distributed lead zirconate titanate piezoelectric (PZT) actuator instead of point force actuator. Using the modal acoustic transfer impedance-mobility matrices, the excitation and interaction in the coupled sound transmission system can be described with clear physical significance. With the control system designed to globally reduce the sound field, different control system configurations were considered, including the structural actuator on the incident plate, actuator on the receiving plate, acoustic actuator on the cavity, and their combinations. The effectiveness and performance of the control strategy corresponding to each system configuration were compared and discussed. The role and control mechanism of each type of actuator were of particular interest. It was shown that the incident plate actuator is effective in controlling the cavity-dominated modes and the structural modes dominated by the incident plate and receiving plate. Two main control mechanisms are involved in this control configuration, i.e., modal suppressing and modal rearrangement. For control system configuration with only acoustic actuator in the enclosure, the mechanism involved in this arrangement is purely modal suppression. Desirable placements of structural actuators in terms of total potential energy reduction were also discussed.展开更多
·Prof.XIONG,could you please give us a brief introduction to SKLMCMS？Director XIONG Ke：The State Key Laboratory of Mechanics and Control of Mechanical Structures（SKLMCMS）was established with the approval of t...·Prof.XIONG,could you please give us a brief introduction to SKLMCMS？Director XIONG Ke：The State Key Laboratory of Mechanics and Control of Mechanical Structures（SKLMCMS）was established with the approval of the Ministry of Science and Technology of the People’s Republic of China in October 2011.The laboratory is located at Nanjing University of Aeronautics and Astronautics（NUAA）.展开更多
Actuators are one of the key points for the development of active flow control technology.Efficient methods of high speed flow control can provide enhanced propulsive efficiency and at the same time enable safe and ma...Actuators are one of the key points for the development of active flow control technology.Efficient methods of high speed flow control can provide enhanced propulsive efficiency and at the same time enable safe and maneuverable high speed flight.The development of high speed flight technology promotes the emergence of novel and robust actuators.This review introduces the state of the art in the development of actuators that can be used in high speed active flow control.The classification and different operation criteria of the actuators are discussed.The specifications,mechanisms and applications of various popular actuator types including fluidic,mechanical,and plasma actuators are described.Based on the realistic need of high speed flow control and the existing results of actuators,a new actuator design method is proposed.At last,the merits and drawbacks of the actuators are summarized and some suggestions on the development of active flow control technology are put forward.展开更多
Herein is introduced the mechanism for active control influencing the generation of the near-wall streamwise vortices,which are closely related to the production of high skin friction in wall-bounded turbulent flows.A...Herein is introduced the mechanism for active control influencing the generation of the near-wall streamwise vortices,which are closely related to the production of high skin friction in wall-bounded turbulent flows.A new opposition control scheme with adjusting control amplitude is proposed and evaluated in turbulent channel flow by direct numerical simulations.The maximum drag reduction rate can be greatly enhanced by the strengthened control.Finally the effectiveness of the control to the coherent structures at high Reynolds numbers is investigated by using a linear transient growth model.展开更多
基金Supported by the National Natural Science Foundation of China (No.10802024)Research Fund for the Doctoral Program of Higher Education of China (No. 200802171009)+1 种基金Innovative Talents Fund of Harbin (No.2009RFQXG211)Fundamental Research Fund of HEU (No. HEUFT08003)
文摘An analytical study was presented on active control of sound transmission into a vibro-acoustic enclosure comprising two flexible plates. Two types of actuators were used, i.e. acoustic actuator and distributed lead zirconate titanate piezoelectric (PZT) actuator instead of point force actuator. Using the modal acoustic transfer impedance-mobility matrices, the excitation and interaction in the coupled sound transmission system can be described with clear physical significance. With the control system designed to globally reduce the sound field, different control system configurations were considered, including the structural actuator on the incident plate, actuator on the receiving plate, acoustic actuator on the cavity, and their combinations. The effectiveness and performance of the control strategy corresponding to each system configuration were compared and discussed. The role and control mechanism of each type of actuator were of particular interest. It was shown that the incident plate actuator is effective in controlling the cavity-dominated modes and the structural modes dominated by the incident plate and receiving plate. Two main control mechanisms are involved in this control configuration, i.e., modal suppressing and modal rearrangement. For control system configuration with only acoustic actuator in the enclosure, the mechanism involved in this arrangement is purely modal suppression. Desirable placements of structural actuators in terms of total potential energy reduction were also discussed.
文摘·Prof.XIONG,could you please give us a brief introduction to SKLMCMS？Director XIONG Ke：The State Key Laboratory of Mechanics and Control of Mechanical Structures（SKLMCMS）was established with the approval of the Ministry of Science and Technology of the People’s Republic of China in October 2011.The laboratory is located at Nanjing University of Aeronautics and Astronautics（NUAA）.
基金supported by the National Natural Science Foundation of China (Grant No. 11002161)the Foundation for the Author of National Excellent Doctor Dissertation of China (Grant No. 201058)the Specialized Research Fund for the Doctor Program of Higher Education of China (Grant No. 20104307110007)
文摘Actuators are one of the key points for the development of active flow control technology.Efficient methods of high speed flow control can provide enhanced propulsive efficiency and at the same time enable safe and maneuverable high speed flight.The development of high speed flight technology promotes the emergence of novel and robust actuators.This review introduces the state of the art in the development of actuators that can be used in high speed active flow control.The classification and different operation criteria of the actuators are discussed.The specifications,mechanisms and applications of various popular actuator types including fluidic,mechanical,and plasma actuators are described.Based on the realistic need of high speed flow control and the existing results of actuators,a new actuator design method is proposed.At last,the merits and drawbacks of the actuators are summarized and some suggestions on the development of active flow control technology are put forward.
基金Tsupported by the National Natural Science Foundation of China (Grant Nos. 10925210 and 11132005)
文摘Herein is introduced the mechanism for active control influencing the generation of the near-wall streamwise vortices,which are closely related to the production of high skin friction in wall-bounded turbulent flows.A new opposition control scheme with adjusting control amplitude is proposed and evaluated in turbulent channel flow by direct numerical simulations.The maximum drag reduction rate can be greatly enhanced by the strengthened control.Finally the effectiveness of the control to the coherent structures at high Reynolds numbers is investigated by using a linear transient growth model.
