大幅振荡试验支架干扰研究

低速风洞大幅振荡试验是飞行器研制，特别是具有过失速机动能力的战斗机研制中，必不可少的试验研究项目。目前国内外已经开展了低速风洞大幅振荡试验，并开展了其他动态试验系统的支架干扰试验研究和大幅振荡试验洞壁干扰的试验研究，但对低速风洞大幅振荡试验结果中的支架干扰修正都没有进行过相应的研究。为了进一步提高低速风洞大幅振荡试验的数据准度，掌握支架干扰影响规律，在 FL-51风洞采用两步法对俯仰、滚转和偏航三个模态的单自由度大幅振荡风洞试验的支架干扰进行了测量。两步法支架干扰修正法使用叠加原理，认为辅助支架、映像支架和主支架对模型气动力的干扰作用都是线性叠加关系，没有考虑不同支架之间的相互干扰。通过设计加工专用的辅助支架和映像支架，利用两步法试验获得了单自由度大幅振荡试验支架干扰的影响量。分析发现大幅振荡试验中支架干扰影响量对单自由度大幅振荡试验的准度影响较大，进行大幅振荡试验时，需要进行相应的支架干扰试验，并且支架干扰影响量随频率增大而增大。结果表明大幅振荡风洞试验可以通过两步法进行支架干扰影响修正，进而提高试验结果的准度。

Investigation of support interference of large amplitude oscillation test

Low speed wind tunnel oscillation test is an essential test research project for the development of aircraft,especially in the development of the aircraft with the capability of post stall maneuver.At home and abroad,the oscillation tests have been carried out in low speed wind tunnel.Experimental study has also been conducted on oscillation and other dynamic system to test the support interference and wall interference;however,the modifications for the support interference have not been studied in low speed wind tunnel oscillation test.In order to improve the accuracy of low speed wind tunnel oscillation test,to understand the mechanism of the support interference in low speed wind tunnel oscillation test,to provide high quality data for accurate prediction of aerodynamic characteristics and highly reliable performance analysis,to improve the logistic security level for aircraft development, the support interference was measured in FL-5 1 wind tunnel by single degree of freedom oscillation test with a two-steps method for three modes,i.e.,pitch,roll and yaw.The two-step method for the support interference correction adopts the principle of superposition.The influence effect of the auxiliary support bracket,the main bracket and image model of aerodynamic forces are linear superposition in this method,without considering the mutual interference among different frames.With the aid of particularly designed and processed support frame and the image frame,the influence of the single degree of freedom oscillation was obtained by the two-step test.It is found that the influence of the support increases with increasing frequency,and the support has significant influence on the accuracy of the single degree of freedom oscillation test.When a large oscillation test is performed,the corresponding support interference test is required.The results show that the two step method can be used to modify the disturbance caused by the bracket,and the accuracy of the test results can be improved.