Volume 16, Issue 10 (1-2017)                   Modares Mechanical Engineering 2017, 16(10): 155-162 | Back to browse issues page

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1- phs student/yazd university
2- assistant professor/yazd university
3- phd student/yazd university
Abstract:   (3999 Views)
Accurate measurement of unsteady pressure fluctuations along a surface requires experimental set up with high spacing resolution and high frequency domain. Therefore, in recent decades extensive studies have been conducted on remote microphone approach. In this method, instead of using flash mounted sensors, they installed remotely and connected to the model surface through one or several continuously connected tubes. Surface pressure fluctuations will travel within the tubing in the form of sound waves and they will be measured when passing over the remote pressure sensor, mounted perpendicular to the tubing. In the present study, an analytical solution of sound waves propagation inside the rigid tubes is used for modelling of the remote microphone system and to investigate the effects of its parameters on dynamic response. In order to verify the accuracy of proposed modeling, the dynamic response of a typical remote microphone has been obtained through experimental calibration. Comparing the analytical and experimental results indicates high accuracy of the analytical modeling. Results show that changes in tubing diameter leads to occurrence of resonance and creating harmonics in two frequency regions. The amplitude of low-frequency harmonics depends on the length of the damping duct and decreases with increasing of its length. Instead, the amplitude and frequency of high-frequency harmonics depend on the length of the first tube and they decrease with the increase of first tube length. Also, Increase of the first and second tube lengths lead to an increase in phase of dynamic response of the remote microphone system.
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Article Type: Research Article | Subject: Aerodynamics
Received: 2016/07/3 | Accepted: 2016/09/18 | Published: 2016/10/9

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