Wind tunnel resonances and Helmholtz resonators
Keywords:Computer simulation, Helmholtz equation, Natural frequencies, Pressure effects, Resonators, Vortex flow, Helmholtz resonators, Jet wind tunnels, Pressure fluctuations, Wind speed
AbstractOpen jet wind tunnels can be impacted by low-frequency pressure fluctuations due to different feedback mechanisms coupling with vortices shed from the nozzle exit. These fluctuations can reduce the simulation quality of the wind tunnel and/or reduce the effective wind speed range of the facility. Considerable research has been conducted to understand the on-set of these strong pressure fluctuations and different mitigation methods have been attempted to reduce these fluctuations. The idea of using Helmholtz resonators to provide strong absorption in the low frequency regime has been around for a long time in different acoustical applications. It has been applied in aero-acoustic fields also to control cavity resonances. A parametric study of applying Helmholtz resonators to control the pressure fluctuations in open-jet wind tunnels was undertaken. An existing open-jet tunnel was modified to produce strong low-frequency pressure fluctuations. A control volume to represent a Helmholtz resonator was attached to the wind tunnel. The control volume was made adjustable to produce different tuning frequencies to control fluctuations at different wind speeds. The results of the study are presented in this paper.
How to Cite
Copyright on articles is held by the author(s). The corresponding author has the right to grant on behalf of all authors and does grant on behalf of all authors, a worldwide exclusive licence (or non-exclusive license for government employees) to the Publishers and its licensees in perpetuity, in all forms, formats and media (whether known now or created in the future)
i) to publish, reproduce, distribute, display and store the Contribution;
ii) to translate the Contribution into other languages, create adaptations, reprints, include within collections and create summaries, extracts and/or, abstracts of the Contribution;
iii) to exploit all subsidiary rights in the Contribution,
iv) to provide the inclusion of electronic links from the Contribution to third party material where-ever it may be located;
v) to licence any third party to do any or all of the above.