Results 131 to 140 of about 252,123 (184)
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Helmholtz resonance of harbours
Journal of Fluid Mechanics, 1975The resonant response of a harbour H of depth scale d and area A to excitation of frequency ω through a mouth M of width a is calculated in the joint limit a2/Aω2A/gd↓0. The results are relevant to the tsunami response of narrow-mouthed harbours. 16 is assumed that an adequate approximation to the radiation impedance of the external domain is available
Miles, John W., Lee, Y. K.
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SPLITTING OF THE POLES OF A HELMHOLTZ RESONATOR
Russian Academy of Sciences. Izvestiya Mathematics, 1994Summary: It is shown that in a neighborhood of a two-fold eigenvalue of the Neumann problem there are two poles of the Green's function of the Helmholtz resonator. Asymptotic expressions for them with respect to a small parameter \(\varepsilon\) (the linear size of the hole) are constructed, and the principal terms of the asymptotics are written out ...
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On the adjustment of Helmholtz resonators
Applied Acoustics, 2014Abstract A Helmholtz resonator is placed in a room with distinct acoustic modes, and is tuned to one of the corresponding resonant frequencies. The optimal resonator damping ratio is investigated, as a goal-dependent value. For example, minimizing reverberation time requires a different damping ratio from minimizing the sound pressure level.
J. Klaus +3 more
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Time domain modelling of a Helmholtz resonator analogue for water waves
Journal of Fluid Mechanics, 2021In the context of water waves, we consider a resonator with deep subwavelength resonance, analogue to the Helmholtz resonator in acoustics. In the shallow water regime, using asymptotic analysis, a one-dimensional model is derived in which the effect of ...
L.-P. Euvé +4 more
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The Journal of the Acoustical Society of America, 1952
The explanation of the acoustical action of multiple Helmholtz resonators, except for one and two cavities, has not been developed. Application of Lagrange's method is made to obtain the equations of motion of the fluid displacements. The equation for the frequencies of resonance is obtained by placing the determinant of the coefficients of the ...
C. S. McGinnis, V. F. Albert
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The explanation of the acoustical action of multiple Helmholtz resonators, except for one and two cavities, has not been developed. Application of Lagrange's method is made to obtain the equations of motion of the fluid displacements. The equation for the frequencies of resonance is obtained by placing the determinant of the coefficients of the ...
C. S. McGinnis, V. F. Albert
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Resonant frequencies of cylindrical Helmholtz resonators
The Journal of the Acoustical Society of America, 1975A simple analysis predicts the Helmholtz and higher modes of cylindrical resonators. Formulas for the quarter-wave tube, the closed tube, and the classic Helmholtz resonator are special cases. It is found that the classic Helmholtz formula begins to lose accuracy for resonator lengths L≳λ/16.
Ronald L. Panton, John M. Miller
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Helmholtz‐Resonator Metasurface Based High‐Efficiency Acoustic Focusing Lens
Annals of Physics, 2021The high‐efficiency transmitted acoustic focusing lenses based on the Helmholtz resonator (HR) metasurface is reported. The proposed lenses demonstrate superior focusing performances, which can provide deep‐subwavelength resolution.
Hongjun Liu +5 more
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The Use of Helmholtz Resonators in a Practical Combustor
Journal of Engineering for Gas Turbines and Power, 2003The drive to reduce emissions has led to the development of lean premixed combustors. However, lean premixed combustion is often associated with combustion oscillations which can be so severe that they can cause structural damage to the engine. Since the associated frequencies are typically of the order of hundreds of Hertz, there is a need for a ...
Dupère, Iain D J, Dowling, Ann P.
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Helmholtz resonator lined with absorbing material
The Journal of the Acoustical Society of America, 2005A closed-form, two-dimensional analytical solution is developed to investigate the acoustic performance of a concentric circular Helmholtz resonator lined with fibrous material. The effect of density and the thickness of the fibrous material in the cavity is examined on the resonance frequency and the transmission loss.
A, Selamet, M B, Xu, I J, Lee, N T, Huff
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Helmholtz resonator loudspeaker
The Journal of the Acoustical Society of America, 1998A Helmholtz resonator loudspeaker having a capsule shape that may be truncated at one or both ends. When the housing is truncated, dampening material may be added at the truncated portion. Legs or a stand aid in the physical stability and to further assist the acoustics.
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