Helmholtz-Like Resonator Self-Sustained Oscillations, Part 1: Acoustical Measurements and Analytical Models
Helmholtz-Like Resonator Self-Sustained Oscillations, Part 1: Acoustical Measurements and Analytical Models
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DOI：
10.2514/2.1991
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发表时间：
2003-03
期刊：
影响因子：
2.5
通讯作者：
S. Dequand;Xisheng Luo;Jfh Jan Willems;A. Hirschberg
中科院分区：
文献类型：
--
作者：
S. Dequand;Xisheng Luo;Jfh Jan Willems;A. Hirschberg
我们考虑类亥姆霍兹谐振器颈部掠流的自持振荡。这种振荡是由剪切层的固有不稳定性和腔内的共振声场之间的耦合驱动的。根据颈部形状的细节，通过谐振器颈部的声速可以达到与主声速相同数量级的声速。对于特定的颈部几何形状，口哨是被抑制的。一个假设剪切层的涡量集中在以恒定速度移动的线涡中的非线性模型提供了对这一现象的洞察。对于圆形边缘，该模型对第一个流体动力模式的脉动幅度的预测出奇地好，但严重高估了较高的流体动力模式的幅度。对于锐边，提出了一种对原模型的修正，它对第一个流体动力模式的脉动幅度(在2倍以内)给出了合理的预测，并且不会高估较高的流体动力模式。
We consider self-sustained oscillations of the grazing e ow along the neck of a Helmholtz-like resonator. Such oscillations are driven by a coupling between the intrinsic instability of the shear layer, separating the main e ow from the cavity, and the resonant acoustical e eld in the cavity. Depending on details of the shape of the neck, acoustical velocities through the neck of the resonator of the same order of magnitude as the main e ow velocity can be reached. For particular neck geometries, whistling is suppressed. A nonlinear model, which assumes that the vorticity of the shear layer is concentrated in line vortices traveling at constant velocity, provides insight into the phenomenon. For rounded edges, the model predicts the pulsation amplitude of the e rst hydrodynamic mode surprisingly well but severely overestimates the amplitude of higher hydrodynamic modes. For sharp edges, a modie cation of the original model is proposed, which yields a reasonable prediction of the pulsation amplitude (within a factor of two ) of the e rst hydrodynamic mode and does not overestimate higher hydrodynamic modes.