Kooijman Gerben, Ouweltjes Okke
Philips Research Laboratories, Eindhoven, The Netherlands.
J Acoust Soc Am. 2009 Apr;125(4):1911-8. doi: 10.1121/1.3081514.
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.
提出了一种用于合成射流致动器的集总元件电声模型。该模型包括与流动分离相关的非线性流动阻力，并在时域中采用有限差分格式。与更常见的解析频域电声模型不同，在解析频域电声模型中非线性电阻只能被视为常数，而该模型允许计算由于这种非线性电阻产生的高次谐波，即失真分量。将合成射流的时间平均动量通量以及辐射声功率谱的模型计算结果与各种配置的实验结果进行了比较。结果表明，当考虑非线性电阻时，对射流动量通量以及流速的预测有显著改善。在此，当前模型的表现略优于解析模型。对于辐射声的功率谱，当假设非线性电阻存在合理的轻微不对称时，可得到合理的一致性结果。然而，结果表明扬声器非线性在最初几个高次谐波的产生中也起着重要作用。
