模型大振幅运动风洞壁面影响实验研究

Experiment Investigation of Unsteady Wall Interference to Model Pitching in Large Angle of Attack

用 3个阻塞度不同的前缘后掠角 70°三角机翼 ,在 3m低速风洞中研究了模型作大振幅俯仰运动 (0°～ 90°)时风洞壁的干扰影响。研究中测量了模型的气动力及力矩特性 ,同时测量了风洞的非定常壁压。研究表明 ,虽然风洞洞壁干扰对非定常气动力及力矩特性有一定影响 ,但是它不影响测量的可信度 ,特别对复杂的力矩特性的本质无影响。另外 ,在模型作俯仰运动时 ,风洞壁压像非定常气动力一样有迟滞环 ,模型越大 。

The wall interference is investigated in a 3 m low speed wind tunnel using three delta wings with the different sizes and the similar figuration pitching i n large angle of attack. The unsteady aerodynamic and moment characteristics of the models and the unsteady wall pressure are measured. It is indicated that the wall interfe rence has some affects on the unsteady aerodynamic and moment characteristics, but does not affect the reliability of measurement to the moment characteristic of the model. By the way, it ca n be found that the unsteady wall pressure forms a hysteresis loop just like the unsteady aerodynamic, and the big the model is,the larger of the hysteresis loo p will be. Comparied the result of unsteady aerodynamic, it can be shown that th e amount of wall interference correcting is about 8.7% for the model of 6.87% bl ock coefficient.