Identification of aerodynamic sound source in the wake of a rotating circular cylinder
Iida, Ayiyoshi, Mizuno, Akisato, & Brown, Richard J. (2004) Identification of aerodynamic sound source in the wake of a rotating circular cylinder. In Behinia, M., Lin, W., & McBain, G.D. (Eds.) 15th Australasian Fluid Mechanics Conference, 13-17 December 2004, Sydney.
In order to reduce aerodynamic noise radiated from the turbulent wake of bluff bodies, vorticity structures and flow field around a rotating circular cylinder at Reynolds numbers between 102 and 104 were numerically investigated. Vorticity structures and resultant aerodynamic noise is strongly dependant on the velocity ratio, which is defined as flow velocity over rotational speed to the cylinder. At low velocity ratio, the noise level and aerodynamic forces increase and an anti-symmetric vorticity structure is observed. On the other hand, the absolute value of lift-drag ratio becomes small and alternative vorticity structure disappears as the velocity ratio exceeds about 2. As a result, the fluctuating aerodynamic forces become weak and the resulting aerodynamic sound becomes small. The noise level of the rotational cylinder is 10 dB lower than that of the conventional circular cylinder. Source terms of aerodynamic sound were also visualized by using vortex sound theory. The intensity of the source term of the separated shear layer rapidly change as the shear layers roll up. Therefore, the separated shear layers play an important role in generating aerodynamic sound at low velocity ratio. Since the anti-symmetric vorticity structure disappears at high velocity ratio, vorticity fluctuation and resultant aerodynamic noise is restrained. As a result, very interestingly, in the case of the high velocity ratio the intensity of the source term generated by the separated shear layer is maintained, however, the noise level gradually decreases. This reveals that cylinder rotation is an effective method for reducing the aerodynamic noise radiated from a turbulent wake.
Impact and interest:
Citation counts are sourced monthly from and citation databases.
These databases contain citations from different subsets of available publications and different time periods and thus the citation count from each is usually different. Some works are not in either database and no count is displayed. Scopus includes citations from articles published in 1996 onwards, and Web of Science® generally from 1980 onwards.
Citations counts from theindexing service can be viewed at the linked Google Scholar™ search.
Full-text downloads displays the total number of times this work’s files (e.g., a PDF) have been downloaded from QUT ePrints as well as the number of downloads in the previous 365 days. The count includes downloads for all files if a work has more than one.
|Item Type:||Conference Paper|
|Additional Information:||The contents of this conference can be freely accessed online via the conference’s web page (see hypertext link).|
|Subjects:||Australian and New Zealand Standard Research Classification > PHYSICAL SCIENCES (020000) > CLASSICAL PHYSICS (020300) > Fluid Physics (020303)
Australian and New Zealand Standard Research Classification > MATHEMATICAL SCIENCES (010000) > NUMERICAL AND COMPUTATIONAL MATHEMATICS (010300) > Numerical Analysis (010301)
Australian and New Zealand Standard Research Classification > ENGINEERING (090000) > AEROSPACE ENGINEERING (090100) > Aerodynamics (excl. Hypersonic Aerodynamics) (090101)
|Divisions:||Past > QUT Faculties & Divisions > Faculty of Built Environment and Engineering|
|Copyright Owner:||Copyright 2004 The University of Sydney|
|Deposited On:||28 Feb 2008|
|Last Modified:||10 Aug 2011 14:50|
Repository Staff Only: item control page