The vibration characteristics of transverse oscillation of an axially moving beam with high velocity is in- vestigated. The vibration equation and boundary conditions of the free-free axially moving beam are derived u...The vibration characteristics of transverse oscillation of an axially moving beam with high velocity is in- vestigated. The vibration equation and boundary conditions of the free-free axially moving beam are derived using Hamilton＇s principle. Furthermore, the linearized equations are set up based on Galerkinl s method for the ap- proximation solution. Finally, three influencing factors on the vibration frequency of the beam are considered： （1） The axially moving speed. The first order natural frequency decreases as the axial velocity increases, so there is a critical velocity of the axially moving beam. （2） The mass loss. The changing of the mass density of some part of the beam increases the beam natural frequencies. （3） The thermal effect.＇ The temperature increase will decrease the beam elastic modulus and induce the vibration frequencies descending.展开更多
This paper focuses on the temperature and pressure characteristics of a Swift-Backhaus type traveling-wave thermoacoustic prime mover during its onset and damping processes,in order to understand the intrinsic mechani...This paper focuses on the temperature and pressure characteristics of a Swift-Backhaus type traveling-wave thermoacoustic prime mover during its onset and damping processes,in order to understand the intrinsic mechanism of thermoacoustic oscillation onset and the feasibility of using low-grade thermal energy based on a low onset temperature. The influences of heat input and filling pressure on hysteretic loop,due to the noncoincidence between onset and damping processes,are measured and analyzed. The condition for the occurrence of hysteresis is also briefly discussed.展开更多
The characteristics of a laminar wall jet submitted to different configurations have been experimentally explored in order to obtain a better knowledge of transition modifications,In fact different parameters can acce...The characteristics of a laminar wall jet submitted to different configurations have been experimentally explored in order to obtain a better knowledge of transition modifications,In fact different parameters can accelerate or delay the transition using a smooth or rough surface,heated or not,submitted to vibrations or not .In this study,significant effects can be noticed.It has been possible to measure the beginning of growth rates of disturbance amplitude using a wind tunnel and comparing the results with the linear stability theory.展开更多
基金Supported by the National Natural Science Foundation of China(10972104)~~
文摘The vibration characteristics of transverse oscillation of an axially moving beam with high velocity is in- vestigated. The vibration equation and boundary conditions of the free-free axially moving beam are derived using Hamilton＇s principle. Furthermore, the linearized equations are set up based on Galerkinl s method for the ap- proximation solution. Finally, three influencing factors on the vibration frequency of the beam are considered： （1） The axially moving speed. The first order natural frequency decreases as the axial velocity increases, so there is a critical velocity of the axially moving beam. （2） The mass loss. The changing of the mass density of some part of the beam increases the beam natural frequencies. （3） The thermal effect.＇ The temperature increase will decrease the beam elastic modulus and induce the vibration frequencies descending.
基金the National Natural Science Foundation of China (Nos. 50776075 and 50536040)the Natural ScienceFoundation of Zhejiang Province (No. Y107229), China
文摘This paper focuses on the temperature and pressure characteristics of a Swift-Backhaus type traveling-wave thermoacoustic prime mover during its onset and damping processes,in order to understand the intrinsic mechanism of thermoacoustic oscillation onset and the feasibility of using low-grade thermal energy based on a low onset temperature. The influences of heat input and filling pressure on hysteretic loop,due to the noncoincidence between onset and damping processes,are measured and analyzed. The condition for the occurrence of hysteresis is also briefly discussed.
文摘The characteristics of a laminar wall jet submitted to different configurations have been experimentally explored in order to obtain a better knowledge of transition modifications,In fact different parameters can accelerate or delay the transition using a smooth or rough surface,heated or not,submitted to vibrations or not .In this study,significant effects can be noticed.It has been possible to measure the beginning of growth rates of disturbance amplitude using a wind tunnel and comparing the results with the linear stability theory.
