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| The formation mechanism of disturbances in self-excited oscillating louver-cavity flows |
| Received:February 21, 2020 Revised:June 08, 2020 |
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| DOI：10.7511/jslx20200221001 |
| KeyWord:louver cavity flow self-excited oscillation flow disturbance numerical simulation |
| Author | Institution |
| 张永昌 |
内蒙古大学 交通学院, 呼和浩特 |
| 孟杨 |
内蒙古大学 交通学院, 呼和浩特 |
| 徐宇工 |
北京交通大学 机械与电子控制工程学院, 北京 |
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| Abstract: |
| Flow past a louvered cavity can give rise to self-excited oscillations which can lead to structural vibrations or noise problems.It is significant to study the formation mechanism of this phenomenon for the design of vibration or noise reduction of related equipment.At present,it is known that this phenomenon is excited under the coupling of the forward and backward disturbances in the flow field.However,the formation mechanism of these two disturbances is not clear.To solve this problem,a numerical model of louver-cavity flow is established and unsteady simulation is carried out.By analyzing the pressure oscillation data and the flow structure evolution process,the formation progress of the two kinds of disturbances is studied.The results show that both the forward and backward disturbances are related to the small-scale vortices formed in the gaps of the louver.The small-scale vortices in the upstream region separate from the gaps of the louver successively and aggregate into large-scale vortices.The forward disturbance of the flow system is excited during this progress.The backward disturbance is composed of disturbing reverse flow caused by the separation of the small-scale vortices in the downstream region and has a continuous positive feedback effect on the forward disturbance. |