Flow Estimation by Flow Induced Vibration of Bluff Bodies

Abstract

The study confirms the feasibility of using information from flow-induced vibration generated by bluff bodies for measurement of flow. The proposed methodology is based on experiments conducted for recording acceleration signals from vibration sensors embedded along with bluff bodies in cross flow. The studies were undertaken in a wide Reynolds number range of 4700 to 5.655x105, with five different geometries of bluff bodies for shape optimization. Resonance and vortex shedding frequencies of samples are determined experimentally. The recorded acceleration signals are analysed using three different techniques such as frequency shift method, resonance amplitude method and overall acceleration estimation method. In this, the frequency shift method shows correlation at low flow velocities. In the resonance amplitude method and overall acceleration method, acceleration levels show a cubic relation with the flow rate. In the resonance amplitude method, obtained R2 values are from 0.93 to 0.99. Overall acceleration estimation method has shown better correlation with flow rate and its R2 values were above 0.99. The study confirms that application of all three methods together yields reasonably good estimation for a wide range of flow.

Keywords

• flow measurement
• vibration measurement
• cross flow
• overall amplitude method
• resonance frequency