英语翻译To provide a contour that vividly shows the footprint of

英语翻译
To provide a contour that vividly shows the footprint of the air- foil noise,the background noise and jet speed were rst measured simultaneously as the ow speed was gradually reduced from its maximum value.This procedure was repeated with the airfoil in- stalled at zero angle of attack (with sandpaper removed).Fig.14a and b show,respectively,the contours of the sound pressure levels plotted as a colour map against frequency and ow speed without and with the airfoil.The resolution of the jet speeds presented in the gure is within 0.3-0.5 m/s.While a low overall background noise level is observed (Fig.14a),a distinct broadband-‘‘hump” can be found for the case of trailing edge self-noise as well as the low frequency noise caused by the ow impingement to the airfoil leading edge at higher jet speeds (both indicated in Fig.14b).When the results were compared with the Brooks et al.’s prediction scheme,although not shown here,both agree extremely well.

To provide a contour that vividly shows the footprint of the air-foil noise, the background noise and jet speed were rst measured simultaneously as the ow speed was gradually reduced from its maximum value. 为了提供生动显示机翼噪声的足迹的轮廓,随着（OW）速度从其最高值逐步降低,对背景噪声和射流速度同时进行了（rst）测量.This procedure was repeated with the airfoil in- stalled at zero angle of attack (with sandpaper removed). 这一程序在机翼以零迎角下（砂纸去除）安装时重复.Fig. 14a and b show, respectively, the contours of the sound pressure levels plotted as a colour map against frequency and ow speed without and with the airfoil. 图14a和b分别示出了有机翼和没有机翼时,声压水平随频率和（OW）速度绘制的轮廓.The resolution of the jet speeds presented in the gure is within 0.3-0.5 m/s. 图中示出的射流速度的分辨率在0.3－0.5 m/s之内.While a low overall background noise level is observed (Fig. 14a), a distinct broadband-‘‘hump” can be found for the case of trailing edge self-noise as well as the low frequency noise caused by the ow impingement to the airfoil leading edge at higher jet speeds (both indicated in Fig. 14b). 尽管观察到了低的总背景噪声水平（图14a）,但在拖尾边缘自噪声的情况下,可以发现一明显的宽带“峰”,以及在较高射流速度下对机翼前缘的（OW）冲击引起的低频噪声（这两者都在图14b中表示了出来）.When the results were compared with the Brooks et al.’s prediction scheme, although not shown here, both agree extremely well. 当这些结果与Brooks等人的预测方案比较时,虽然这里没有表示出来,但两者的一致性都很好.