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本文根据在西德宇航院跨音速风洞(TWB)进行的翼型油流试验结果对风洞侧壁效应的机理进行了研究。研究表明,传统的关于侧壁效应的概念和理论只能适用于亚临界流动。在超临界情况下,侧壁效应的表现远为复杂,影响远为严重,但是至今很少得到研究。本文将风洞试验的翼型油流谱分为五类,对每种流谱都作了详细的讨论。阐明了侧壁影响发生作用的机理,首次研究了超临界翼型试验真实油流谱的各种复杂结构形式,解释了它们和侧壁效应之间的关系,指出侧壁效应主要来源于侧壁附面层的位移效应,并对油流谱的发展规律作出了系统的说明。文中指出,老式的实侧壁“二元”风洞对跨音速翼型试验已完全不能适应。增加风洞宽度可以减小、但不能保证免除侧壁干扰。油流照片表明,即使风洞宽度达到翼型弦长的3.4倍,中心截面上的流动仍然不能保证免除侧壁的明显影响。文中认为,根据侧壁扰动来源于附面层位移效应的原理,侧壁抽气技术作为克服侧壁效应的手段是很有希望的。
Based on the results of the airfoil oil flow test conducted at the Transonic Wind Tunnel (TWB) in West German Aerospace Institute, the mechanism of the sidewall effect of the wind tunnel is studied in this paper. The research shows that the traditional concept and theory of sidewall effect can only be applied to subcritical flow. In the case of supercritical conditions, the performance of the sidewall effect is far more complex and the impact is far worse, but so far it has not been studied. In this paper, the airfoil oil flow spectrum of wind tunnel test is divided into five categories, each of which is discussed in detail. The mechanism of the influence of side wall is clarified. The complex structures of the real oil flow spectrum of the supercritical airfoil are studied for the first time. The relationship between them and the effect of the side wall is explained. The side wall effect is mainly derived from the side wall Displacement effect of surface layer, and made a systematic explanation of the law of oil flow development. It is pointed out in the paper that the old-fashioned “dual” wind tunnel on the side wall can not adapt to the transonic airfoil. Increasing the width of the wind tunnel can be reduced, but the side wall interference can not be guaranteed. The oil flow photos show that even with a wind tunnel width of 3.4 times the chord of the airfoil, the flow at the central cross-section still does not guarantee the significant effect of eliminating the sidewalls. According to the paper, according to the principle that the side-wall disturbance comes from the displacement effect of the top coat, the side-wall pumping technology is very promising as a means to overcome the side-wall effect.