Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh Medical Center, 966 Scaife Hall Floor, 3550 Terrace Street, Pittsburgh, Pennsylvania 15213, USA.
J Acoust Soc Am. 2011 Dec;130(6):3590-4. doi: 10.1121/1.3652868.
In previous research [Raspet et al., J. Acoust. Soc. Am. 123(3), 1260-1269 (2008)], predictions of the low frequency turbulence-turbulence and turbulence-mean shear interaction pressure spectra measured by a large wind screen were developed and compared to the spectra measured using large spherical wind screens in the flow. The predictions and measurements agreed well except at very low frequencies where the turbulence-mean shear contribution dominated the turbulence-turbulence interaction pressure. In this region the predicted turbulence-mean shear interaction pressure did not show consistent agreement with microphone measurements. The predicted levels were often much larger than the measured results. This paper applies methods developed to predict the turbulence-shear interaction pressure measured at the ground [Yu et al., J. Acoust. Soc. Am. 129(2), 622-632 (2011)] to improve the prediction of the turbulence-shear interaction pressure above the ground surface by incorporating a realistic wind velocity profile and realistic turbulence anisotropy. The revised prediction of the turbulence-shear interaction pressure spectra compares favorably with wind-screen microphone measurements in large wind screens at low frequency.
在之前的研究中[Raspet 等人，J. Acoust. Soc. Am. 123(3), 1260-1269 (2008)]，我们提出并比较了通过大风屏测量的低频湍流-湍流和湍流-平均切变相互作用压力谱的预测值，以及通过大球形风屏在流场中测量的谱。预测值和测量值吻合较好，除了在非常低频的情况下，此时湍流-平均切变的贡献主导了湍流-湍流相互作用压力。在该区域，预测的湍流-平均切变相互作用压力与麦克风测量值没有一致的吻合。预测值往往比测量结果大得多。本文应用预测地面上测量的湍流-切变相互作用压力的方法[Yu 等人，J. Acoust. Soc. Am. 129(2), 622-632 (2011)]，通过合并实际风速剖面和实际湍流各向异性，改进地面以上的湍流-切变相互作用压力的预测。修正后的湍流-切变相互作用压力谱的预测值与低频大风屏中麦克风的测量值吻合较好。
