T型尾翼风洞颤振实验保护装置绕流特性分析

采用SST两方程湍流模型,通过求解非定常Navier-Stokes（N-S）方程,对T型尾翼风洞实验流场进行了模拟,分析了保护装置对T型尾翼风洞实验流场的影响,研究了保护装置几何外形和保护装置基座后移距离对流场影响。通过对平尾气动力的分析以及对非定常流场的对比,可以得出：采用NACA系列翼型对基座进行气动整流后,基座两侧局部超声速区显著减小,局部激波减弱甚至消失,流场品质得到改善。且采用NACA0010翼型对基座修形后的结果最理想。随着保护装置基座后移距离的增加,平尾气动力均方根值和波动值先是急剧减小,达到0.85倍平均气动弦长后开始有所增大,在2.45～4.05倍平均气动弦长范围基本不再变化,稳定到单独T型尾翼模型相应系数1倍左右。此结论对T型尾翼风洞颤振实验保护装置设计具有一定的指导意义。

Improvement of shielding-test-facilities for the T-tails in flutter wind-tunnel experiments

The unsteady flow around the T-tails flutter model with a set of shielding-test-facilities in wind tunnel experiments were solved by applying Reynolds-Averaged Navier-Stokes（RANS）equations with SST turbulence model.Two key points were studied,one was the section shapes along airflow for shielding-test-facilities;the other was the distance between the shielding-test-facilities and the T-tails wind tunnel model.The aerodynamic bending-moments and normal-forces indexes versus the calculating time-step were presented.When a series of NACA airfoils（NACA0010-airfoil,NACA0015-airfoil,NACA0021-airfoil）were selected to enwrap the base of shielding-test-facilities,the characteristics of the flow around the T-tails flutter model with the modified shielding-test-facilities were running to quasi-steady.The strength of shock wave decreasing and the vibration of shock wave fading were deduced to the whys.The improvement of NACA0010-airfoil was much better than the others.The Root-Mean-Square（RMS）and the amplitude in the first period for the aerodynamic coefficients（bending-moments and normalforces）versus the distance between the shielding-test-facilities and the T-tails flutter model were figured out.When the distance between the shielding-test-facilities and the T-tails wind tunnel model was increased from 2.45cto 4.05c（c was the mean-aerodynamic chord of vertical-fin）,the aerodynamic coefficients were almost constant.