Kleine Vitor G, Sasaki Kenzo, Cavalieri André V G, Brès Guillaume A, Colonius Tim
Division of Aeronautical Engineering, Instituto Tecnológico de Aeronáutica, São José dos Campos, São Paulo, 12228-900, Brazil.
Cascade Technologies Incorporated, Palo Alto, California 94303, USA.
J Acoust Soc Am. 2021 Dec;150(6):4297. doi: 10.1121/10.0008973.
Parabolized stability equations (PSE) have been shown to model wavepackets and, consequently, the near-field of turbulent jets with reasonable accuracy. In this work, PSE were employed to obtain a reduced-order model that could estimate both the fluid-dynamic and the acoustic fields of a supersonic jet in a computationally efficient approximation for resolvent-based estimation based on a single input. From the unsteady pressure data at an input position, the time-domain pressure field was estimated using transfer functions obtained using PSE and a data-driven method based on a well-validated large-eddy simulation (LES). The prediction scheme employed is a single-input single-output, linear model. The unsteady pressure predicted by the PSE showed good agreement with the LES results, especially if the input position is outside the mixing layer, where the prediction capabilities of the PSE are comparable to those of the data-driven transfer functions. The good agreement indicates that PSE could not only be used to predict the sound generation but also to open up different potentialities to attenuate the noise by flow control. The exploration of the regions where the method displayed good agreement, which are presented in this work, can guide the positioning of the sensors for experimental implementation of closed-loop control in a jet.
抛物化稳定性方程（PSE）已被证明能够对波包进行建模，因此能够以合理的精度模拟湍流射流的近场。在这项工作中，使用PSE来获得一个降阶模型，该模型能够在基于单个输入的基于分解的估计的计算有效近似中，估计超音速射流的流体动力学和声学场。根据输入位置处的非定常压力数据，使用通过PSE获得的传递函数以及基于经过充分验证的大涡模拟（LES）的数据驱动方法来估计时域压力场。所采用的预测方案是单输入单输出线性模型。PSE预测的非定常压力与LES结果显示出良好的一致性，特别是当输入位置在混合层之外时，此时PSE的预测能力与数据驱动传递函数的预测能力相当。良好的一致性表明，PSE不仅可用于预测声音的产生，还可为通过流动控制来减弱噪声开辟不同的潜力。本文所展示的对该方法显示出良好一致性的区域的探索，可指导用于射流闭环控制实验实施的传感器的定位。
