Aeroacoustics of 2D and 3D Surface Discontinuities
Aeroacoustics of 2D and 3D Surface Discontinuities
复制标题
2D 和 3D 表面不连续性的空气声学
DOI：
10.2514/6.2014-2461
复制
发表时间：
2014
影响因子：
0.4
通讯作者：
S. Glegg
中科院分区：
文献类型：
--
作者：
M. Awasthi;W. Devenport;T. Meyers;W. N. Alexander;S. Glegg
在低马赫数壁面射流边界层上，对掠角分别为0、5、15和30的前掠台阶进行了远场声压波动测量。对于每个扫描角，检查了外部台阶角的舍入效果，拐角半径与台阶高度的比率分别为0%、12.5%、25%和50%。当按步距法向速度进行缩放时，尖锐和圆角的向前步所产生的声音几乎与扫频无关，至少在扫频角为30和舍入半径为步距高度的25%时是如此。对于相对于接近流固定的观察者位置，这种行为是模糊的，可能是因为有限跨度和不同掠角下展向非均匀性的不平等影响。步进下游的表面压力波动显示出近似的扫描无关性，限制在更低的频率内，舍入半径高达步进高度的12.5%。
Far field sound and pressure fluctuation measurements have been performed in a low Mach number wall-jet boundary layer flow over a swept forward facing step with sweep angles of 0 , 5 , 15 and 30 . For each sweep angle the effects of rounding of the external step corner were examined for corner radii to step height ratios of 0%, 12.5%, 25% and 50%. When scaled on the step-normal velocity, the sound produced by sharp and rounded forward steps appears almost sweep independent, at least for sweep angles up to 30 and rounding radii up to 25% of the step height. This behavior is obscured for observer locations fixed with respect to the approach flow, perhaps because of the unequal effects of the finite span and spanwise non-uniformity at different sweep angles. Surface pressure fluctuations immediately downstream of the step show approximate sweep independence limited to lower frequencies for rounding radii up to 12.5% of the step height.