I'm looking for experimental data/papers of flow-induced noise by free jets and flow through pinholes and gaps.
For a acoustics simulation I want to set up the source of noise as boundary condition. For this I'm searching for relations between flow (density, velocity) and frequency as well as flow and sound pressure level.
Many thanks, Michael Rembe
Hello Mr M Rembe: A very interesting research area : May be the following links will prove helpful https://pdfs.semanticscholar.org/9641/933836fe554d00a3ff67502d3c036c008c00.pdf
https://scholarcommons.usf.edu/cgi/viewcontent.cgi?article=6881&context=etd
"electrodes can induce a flow from the upper to lower electrode by means of ... noise control; vortices; wind tunnel experiments; acoustic sources. 1. Introduction. Self-sustained oscillations in a flow over a cavity as shown in Figure 1—such ... l actuators, such as a piezo-actuator, an impinging jet, or a synthet."
Experimental Tests and Aeroacoustic Simulations of ... - MDPI
PDFby H Yokoyama - 2017
I do hope the input helps you along. Best wishes--
Dear Michael,
I just added to Researchgate some data we reported on this subject in NAG journal 129 (Nederlandse Akoestisch Genootschap). We considered sound produces by slits and small circular perforations in a plate blocking a pipe. The pressure across the plate was varied between 2 en 70 bar. Aim was to predict sound produced in a pipe by a leaky valve. Yours sincerely, Mico
It is important to realise that the frequency spectrum radiated by jets formed by a circular perforation can be quite different than that produced by slits. For subsonic jets there is a lot of literature concerning circular orifices. The only paper I know for slits is: Bjorno, L. & Larsen, P.N., Noise of air jets from rectangular slits, Acustica 54 (1984) 247-256. This paper focus on broad band noise associated with turbulence.
In subsonic jets one can observe whistling (self-sustained oscillation) with a typical line spectrum. This depends on the shape of the orifice.
When associated with a cavity resonance this is similar to human whistling (
Wilson, T.A., Beavers, G.S., De Coster, M.A., Holger, D.K. & Regenfuss, D., Exper- iments on the fluid mechanics of whistling, J. Acoust. Soc. Am. 50 (1971) 366-372. ). See also:
STRUCTURE AND VELOCITY OF THE PERIODIC VORTEX-RING FLOW PATTERN OF A PRIMARY PFEIFENTON (PIPE TONE) JET By: ANDERSON, ABC JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA Volume: 27 Issue: 6 Pages: 1048-1053 Published: 1955
The whistling potentiality of an orifice in a confined flow using an energetic criterion By: Testud, P.; Auregan, Y.; Moussou, P.; et al. JOURNAL OF SOUND AND VIBRATION Volume: 325 Issue: 4-5 Pages: 769-780 Published: SEP 11 2009
For supersonic jets, jets emerging from slits will display stronger "jet-schreech" type oscillation than circular jets. See nice visualisation of the phenomenon: Jet screech of under-expanded planar supersonic jet L.Poldervaart, G. Vossers, A.P.J.Wijnands (https://www.youtube.com/watch?v=dJp5m1SDN5c)). Jet screech is due to interaction of vortices shed at the orifice outlet with periodic standing shocks in an under-expanded jet. This results in a line spectrum associated with a self-sustained periodic sound generation.
Of course this reference is a classical for subsonic free jets with circular cross section.
JET NOISE By: FISHER, MJ; LUSH, PA; BOURNE, MH JOURNAL OF SOUND AND VIBRATION Volume: 28 Issue: 3 Pages: 563-585 Published: 1973
Chapter 5 of the Phd Thesis of Marc-Pierre Verge provides empirical information about the broad-band spectrum generated by turbulence in an organ pipe:
https://pure.tue.nl/ws/files/3429613/445111.pdf
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