英语翻译中文四The background noises of the open jet wind tunnel were rst measured in the absence of the airfoil at the jet speeds, vj of33.3 m/s and 80 m/s. The airfoil, with rough sandpaper placed near the leading edg

英语翻译中文四The background noises of the open jet wind tunnel were rst measured in the absence of the airfoil at the jet speeds, vj of33.3 m/s and 80 m/s. The airfoil, with rough sandpaper placed near the leading edg
英语翻译中文四
The background noises of the open jet wind tunnel were rst measured in the absence of the airfoil at the jet speeds, vj of
33.3 m/s and 80 m/s. The airfoil, with rough sandpaper placed near the leading edge on both the pressure and suction sides to trip the boundary layer into becoming turbulent, was then attached to the
sidewalls and the measurement repeated at vj = 33.3 m/s. The
resulting narrowband noise spectra are plotted in Fig. 13b. Also
shown in the gure are the predictions of trailing edge self-noise spectra obtained from the empirical prediction scheme developed by Brooks et al. [6] as well as the background noise. The result sug- gests that, in the low frequency range between 100 Hz and 400 Hz, airfoil leading edge noise (triggered by the impingements of exit jet and the side plate turbulent boundary layers on the leading edge) and the side plate edge noise are the dominant noise sources. At higher frequencies, good agreement between the experiment re- sult and Brooks et al.’s prediction is observed over the frequency range of 0.5-6 kHz, thereby con rming that the measured noise is predominantly trailing edge self-noise in origin. In this measure- ment the broadband trailing edge noise is seen to be more than
15 dB above the background noise level at the peak frequency of
1 kHz and more than 10 dB at other frequencies.
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英语翻译中文四The background noises of the open jet wind tunnel were rst measured in the absence of the airfoil at the jet speeds, vj of33.3 m/s and 80 m/s. The airfoil, with rough sandpaper placed near the leading edg
The background noises of the open jet wind tunnel were rst measured in the absence of the airfoil at the jet speeds,vj of 33.3 m/s and 80 m/s.开放式风洞的背景噪声在射流速度vj为33.3m/s和80m/s时,在不存在机翼的情况下进行了（rst）测量.The airfoil,with rough sandpaper placed near the leading edge on both the pressure and suction sides to trip the boundary layer into becoming turbulent,was then attached to the sidewalls and the measurement repeated at vj = 33.3 m/s.然后将机翼附于侧壁,在33.3 m/s的射流速度下重复进行测量,机翼在靠近前缘压力侧和吸入侧放上粗糙的砂纸,以使边界层跳脱（trip）成湍流的.The resulting narrowband noise spectra are plotted in Fig.13b.结果的窄带噪声谱示于图13b.Also shown in the gure are the predictions of trailing edge self-noise spectra obtained from the empirical prediction scheme developed by Brooks et al.[6] as well as the background noise.图中还示出了拖尾边缘的自噪声谱的预测值,它们来自于Brooks等人开发的经验预测方案【6】,以及示出了背景噪声.The result sug- gests that,in the low frequency range between 100 Hz and 400 Hz,airfoil leading edge noise (triggered by the impingements of exit jet and the side plate turbulent boundary layers on the leading edge) and the side plate edge noise are the dominant noise sources.结果表明,在100 Hz和400Hz之间的低频范围内,机翼前缘的噪声（因出口射流及侧板湍流边界层对前缘的冲击触发）,以及侧板的边缘噪声是处于主导地位的噪声源.At higher frequencies,good agreement between the experiment result and Brooks et al.’s prediction is observed over the frequency range of 0.5-6 kHz,thereby con rming that the measured noise is predominantly trailing edge self-noise in origin.在较高的频率下,在实验结果和Brooks等人的预测值之间,在0.5－6kHz频率范围内,一致性良好,因此证实了测得的噪声,起源主要是拖尾边缘的自噪声.In this measure- ment the broadband trailing edge noise is seen to be more than 15 dB above the background noise level at the peak frequency of 1 kHz and more than 10 dB at other frequencies.在这一测量中,在1kHz的峰值频率以上,看到宽带拖尾边缘噪声比背景噪声水平高15dB以上,而在其他频率下则超过10 dB以上.

背景噪声的开放式射流风洞是第一衡量缺席的情况下翼型喷气速度，南军的
三十三点三米/ s和80米/秒翼型，与粗砂纸放在靠近前沿上的压力和吸力双方边界层行到成为动荡，当时隶属
侧壁和测量一再在南军=三十三点三米/ s的那个
由此产生的窄带噪声谱绘制的图。 13B条。也
显示在gure是预测尾缘自噪声谱得到实证预测计划开发的布鲁克斯等。 [ 6 ] ，以及背景噪音...

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背景噪声的开放式射流风洞是第一衡量缺席的情况下翼型喷气速度，南军的
三十三点三米/ s和80米/秒翼型，与粗砂纸放在靠近前沿上的压力和吸力双方边界层行到成为动荡，当时隶属
侧壁和测量一再在南军=三十三点三米/ s的那个
由此产生的窄带噪声谱绘制的图。 13B条。也
显示在gure是预测尾缘自噪声谱得到实证预测计划开发的布鲁克斯等。 [ 6 ] ，以及背景噪音。结果sug - gests认为，在低频率范围内的100赫兹和400赫兹，机翼前缘噪声（所引发impingements出口射流和侧面板湍流边界层的领先优势）和侧面板边缘噪声主要噪声源。在更高的频率，良好的实验之间的协议重新sult和布鲁克斯等人。的预测观察到的频率范围0.5-6千赫，从而节能rming测量噪声的主要是缘自噪声的来源。在此测量的宽带尾缘噪音被认为是多
15分贝以上的背景噪声水平，峰值频率的
1千赫和10分贝以上的其他频率。
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开放喷气机风洞的背景噪声是在没有副翼时被测量的33.3 m/s rst以喷气机速度， vj和80 m/s。 副翼，当粗砺的沙纸在前进附近被安置在压力和吸支持绊倒界面层入变得动荡，然后附有了侧壁和测量被重覆在vj = 33.3 m/s。发生的窄频带噪声光谱被密谋在。 13b. 并且在gure显示机体后缘从经验主义的预言计划得到的自已噪声光谱的预言等开发由Brooks。 [6]并且背景噪声。在低频率范...

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开放喷气机风洞的背景噪声是在没有副翼时被测量的33.3 m/s rst以喷气机速度， vj和80 m/s。 副翼，当粗砺的沙纸在前进附近被安置在压力和吸支持绊倒界面层入变得动荡，然后附有了侧壁和测量被重覆在vj = 33.3 m/s。发生的窄频带噪声光谱被密谋在。 13b. 并且在gure显示机体后缘从经验主义的预言计划得到的自已噪声光谱的预言等开发由Brooks。 [6]并且背景噪声。在低频率范围在100赫兹和400赫兹之间，副翼前进噪声的结果sug- gests (触发由出口喷气机impingements和旁边板材动荡界面层在前进)和旁边板材边缘噪声是统治噪声源。
以更高的频率，利益协定在实验之间关于sult和溪预言等被观察在0.5-6千赫的频率范围，从而精读rming被测量的噪声是主要地机体后缘自已噪声在起源。
在这项措施ment宽频机体后缘噪声看是超过15 dB在背景噪声水平之上以1千赫高峰频率和超过10 dB以其他频率

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