A lumped element electroacoustic model for a synthetic jet actuator is presented. The model includes the nonlinear flow resistance associated with flow separation and employs a finite difference scheme in the time domain. As opposed to more common analytical frequency domain electroacoustic models, in which the nonlinear resistance can only be considered as a constant, it allows the calculation of higher harmonics, i.e., distortion components, generated as a result of this nonlinear resistance. Model calculations for the time-averaged momentum flux of the synthetic jet as well as the radiated sound power spectrum are compared to experimental results for various configurations. It is shown that a significantly improved prediction of the momentum flux-and thus flow velocity-of the jet is obtained when including the nonlinear resistance. Here, the current model performs slightly better than an analytical model. For the power spectrum of radiated sound, a reasonable agreement is obtained when assuming a plausible slight asymmetry in the nonlinear resistance. However, results suggest that loudspeaker nonlinearities play a significant role as well in the generation of the first few higher harmonics.
Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers)Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. AbstractThe paper discusses experimental results for a typical embodiment of synthetic jet cooling technology: an acoustic dipole cooler comprised of a standard loudspeaker in a housing provided with two pipes. A transient measurement set up is used to measure the average heat transfer coefficient based on cooling a 5*5 cm 2 metal plate. Heat transfer and noise results are presented for a range of frequencies, pipe lengths and diameters. The results are compared with a standard 60*60 mm fan. It is concluded that, at least for the cases studied, the synthetic jet is superior on all fronts: heat transfer performance, noise level and dissipated power.
Tibetan singing bowls are employed worldwide for meditation, music, relaxation, personal wellbeing, and religious practices. Each Tibetan bowl can produce a limited number of sounds, defined by the size and material of the bowl, and the actuator device used. Usually, there is a need for a second person to actuate the bowl. Addressing these limitations, we built an electronic device, named eBowl, which can mimic the acoustics of Tibetan bowls, and beyond that, can produce a wide range of other sounds. Furthermore, it can be used for relaxation and sound massage without the need for a second person. The eBowl generates auditory beats that are in EEG alpha frequency range, which can cause brainwave entrainment and lead to relaxation. User tests measuring physiological parameters revealed the eBowl's effectiveness for relaxation, showing that eBowl influences skin conductance, heart rate, and respiration rate and induces relaxation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.