Unsteady surface pressure characteristics of asymmetrically beveled trailing edges
Unsteady surface pressure characteristics of asymmetrically beveled trailing edges
复制标题
非对称斜角后缘的非定常表面压力特性
作者：
Yaoyi Guan;S. Pröbsting;S. Morris
对非对称斜后缘族的非定常表面压力特性进行了实验研究。几何形状有一个后缘角$$ heta = 25 ^circ $$θ=25 °，下表面为平的，上表面为圆的，曲率半径在0到10倍翼型厚度之间。雷诺数为Re=2.1 imes 10^6$$Re=2.1×106（基于和弦）。分别采用远程麦克风探头（RMP）和粒子图像测速仪（PIV）获得了USP和后缘周围流场的详细描述。较低的表面表现出USP自动频谱密度的幅度，类似于那些在较高频率的零压力梯度湍流边界层。低频压力波动受湍流尾流的影响，导致靠近后缘的幅度大幅增加。这些结果的经验模型提出。倾斜的上表面的特征在于有利的压力梯度区域，随后是强烈的不利压力梯度。曲率半径较小的情况下，发现在后缘上表现出分离流。在这些地区的光谱幅度是最大的，并给予显着的注意，这些结果的适当缩放。PIV测量为此目的提供了长度和速度尺度。
The characteristics of unsteady surface pressure (USP) created by turbulent flow over a family of asymmetrically beveled trailing edges were studied experimentally. The geometries had a trailing edge angle $$ heta =25^circ$$θ=25∘ with a flat lower surface and a rounded upper surface with radii of curvature between zero and ten times the airfoil thickness. The Reynolds number was $$Re=2.1 imes 10^6$$Re=2.1×106 based on chord. A detailed description of the USP and flow field around the trailing edge was obtained using remote microphone probes (RMP) and particle image velocimetry (PIV), respectively. The lower surface exhibited USP auto-spectral density magnitudes that were similar to those of a zero-pressure-gradient turbulent boundary layer at higher frequency. The low-frequency pressure fluctuations were influenced by the turbulent wake, leading to large increases in magnitude closer to the trailing edge. An empirical model of these results is proposed. The beveled upper surface was characterized by a region of favorable pressure gradient, followed by a strong adverse pressure gradient. The cases with smaller radius of curvature were found to exhibit separated flow over the trailing edge. The spectral magnitudes were largest in these regions, and significant attention is given to the proper scaling of these results. The PIV measurements provided the length and velocity scales for this purpose.