The role of acoustic resonances in unsteady turbomachinery aerodynamics
Abstract
The role of acoustic resonances in the unsteady aerodynamics of turbomachinery, with the term resonance taken to include all phenomena that occur close to the cut-off of acoustic waves upstream and downstream of a cascade and which result in sudden changes in the response of the cascade, is discussed. Examples of acoustic resonances as they affect two-dimensional calculations of blade flutter with attached flow are illustrated by calculations for flat plates and turbine blades. In the former case the blade loading goes to zero at the cut-on condition, but in the latter there can be sharp peaks in the response. The self-excited resonances that can occur when vortex shedding from the blade trailing edges couples into an acoustic resonance of the blade row is considered. It is shown how many of the features of these resonances can be explained by a simple semiactuator disk model of the flow.
- Publication:
-
Presented at the 4th Symposium on the Unsteady Aerodynamics and Aeroelasticity of Turbomachines and Propellers
- Pub Date:
- October 1987
- Bibcode:
- 1987uaat.symp....6C
- Keywords:
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- Aeroacoustics;
- Aerodynamics;
- Resonant Vibration;
- Sound Waves;
- Turbomachinery;
- Unsteady Flow;
- Actuator Disks;
- Cascade Flow;
- Flutter Analysis;
- Self Excitation;
- Trailing Edges;
- Acoustics