Venturi Tubes: Acoustic Attenuation With Flow Loss Considerations

Abstract

The acoustic wave attenuation performance of Venturi tubes with zero mean fluid flow is investigated by: (1) combining analytical solutions for one-dimensional wave propagation in conical reducers, diffusers, and straight ducts; (2) employing a computational time-domain technique; and (3) conducting experiments in an extended impedance tube setup with four fabricated Venturi tubes and matching contraction chambers. The results from both analytical and computational approaches compare well with each other and the experimental data. The numerical technique is also applied to address the effects of a compressible mean flow on the acoustic behavior. Finally, the flow performance of the fabricated Venturi tubes is measured and the trade-offs are discussed between flow efficiency and acoustic performance.

Wave attenuation by universal Venturi tubes: Finite difference predictions with analytical and experimental comparisons

“…The increase in noise attenuation with increasing m is expected since the duct to throat crosssectional area change dominates the amount of reflection from the element. The observed broadband attenuation and its increase with m resemble the behavior of the limiting simpler configurations, such as contraction and expansion chambers, as elaborated in Selamet et al 9 Experimental results in Fig. 4 show, for the frequency range of 400-800 Hz, small but persistent deviations, which may be attributed to slight imperfections in the anechoic termination leading to some length-controlled reflections.…”

“…9,20 Decreasing the throat to duct cross-sectional area ratio increases the sound attenuation at the expense of deteriorating flow efficiency. Thus the magnitude of noise suppression needs to be weighed against the flow efficiency, particularly at high flow rates, leading to a compromise.…”

“…The noise attenuation performance of classical Venturi structures, however, has received little attention until recently. 8,9 The objective of the present study is ͑1͒ to investigate the noise attenuation performance of anechoically terminated UVTs in the absence of mean flow, using analytical, computational, and experimental approaches; and ͑2͒ to examine the effect of bulk fluid motion on the acoustic performance of UVTs computationally. The working fluid is air at atmospheric conditions.…”