Analysis on the sound speed measurement results differences for the purely longitudinal modes using a fixed path acoustic cylindrical resonator

作者：An Bao Lin^*; Liu Qiang; Duan Yuan Yuan

来源：Journal of Engineering Thermophysics, 2014, 35(10): 1901-1905.

• Acoustic theory
• Boundary influences
• Cylindrical resonator
• Fixed path resonators
• Longitudinal modes
• Resonance frequencies
• Shell vibration
• Sound speed

The gaseous sound speed is one of the basic thermophysical properties of fluids, and can be measured accurately using a fixed path acoustic cylindrical resonator. The purely longitudinal modes are widely used in the sound speed measurements using an acoustic cylindrical resonator. However, the differences among the sound speed measurement results from different longitudinal modes always exist. In this paper, the differences were analyzed from acoustic theory to experiment, in order to give useful guidelines for the selection of the purely longitudinal modes. The results show that the odd modes show advantage on the influence of shell hole while the even modes shows advantage on the influence of shell vibration; the larger mode number means lager relaxation influence and smaller boundary influence; the differences of the corrected measurement results will be very small for the modes whose resonance frequencies are far from the acoustic resonator natural frequencies.

• 出版日期2014
• 单位清华大学