端板法翼型实验的数据处理与洞壁干扰修正方法

THE WALL INTERFERENCE CORRECTION AND TEST DATA PROCESSING METHODS FOR AIRFOIL WIND TUNNEL TEST WITH ENDPLATES

用端板法测量气动力数据时,端板附近有自由涡拖出。通过实验观察假设了端板翼型实验的涡系模型。由涡系模型可计算出机翼加端板后的有效展弦比,再按举力线理论可将实验结果转换成二维(翼型)数据;按镜象法也可作升力洞壁干扰修正。对于端板法中间剖面的测压结果亦应作二维转换和洞壁干扰修正,方法类似。经过这样的数据处理后,翼型数据准确可靠。

In the conventional airfoil tests using, end-plates, the free vortex may be drawn around end-plates. Based on the experimental observations, the vortex system model for such an airfoil test was established. Using the model, the effective aspect ratio of the wins with the end-plates may be found, and then the results can be transformed into 2 -D data by lifting line theory and the wall interference can be corrected by image method. Even for the pressure results on middle sections of the model with end plates, 2-D transformation and wall correction are necessary, in the way similar to force tests. Such the data reduction process will ensure accurate and reliable airfoil results. Some experimental demonstration evidences are presented in this paper for several different airfoils in two wind tunnels with close and open jet respectively.