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

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.

提供一个轮廓,生动地展示了空中的足迹,烘托噪声、背景噪声和喷气速度rst同时测量的速度逐渐雪从它的最大值。这个过程中再次在0 -翼角(用砂纸移除)。图显示,和b。14a的规定,在各自的声压等级轮廓绘制颜色与地图攻击频率和现在的速度,而不与翼型。这项决议的喷气机的速度之间的关系,提出了在gure 0.3 - 0.5米内付款的汇票。虽然低整体背景噪声水平是观察(图)、鲜明。14a的规定,“驼峰”宽带可...

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...