层流翼型三维边界层横流驻波精确测量方法研究

On the Accurate Measurement Method of Standing Cross-flow for Three-dimensional Laminar Airfoil Boundary Layer

后掠机翼的层流控制对于气动减阻有着重要的意义,同时也是非常复杂的研究课题。而对横流驻波的研究是实现层流翼型的一个关键。为此,本文分析并研究了在低湍流度风洞中,采用热线风速仪(CTA)与表面升华法相结合研究由横流不稳定性产生的驻波及其对转捩影响的实验技术,阐述了该实验中架设热线测量系统与升华法表面喷涂的相关技术与细节。实验得到了边界层内的速度剖面图、升华法图形、驻波间距和楔形转捩线。实验结果的综合分析表明热线和升华法一致性很高。说明通过热线风速仪可以方便地测得三维边界层内的流动状态,热线支架在合适的角度下不会影响测量结果,热线探头在测量中对边界层流场的影响较小。所以热线测量的结果可以视作实际流场。研究结果说明,这种研究驻波的方法是可靠而且十分有效的。

Laminar flow control（LFC） of swept-back wing is a complex but very significant topic for drag reduction.The study of standing cross-flow has a great significance for LFC.For this reason,the experimental method of standing cross-flow measurement was analyzed and studied by using hot wire anemometer and sublimation method in a low turbulence wind tunnel.Corresponding technical details about the setup of hot wire anemometer system and process of sublimation surface spray are elaborated in this paper.The velocity profile curve in boundary layer,the image of sublimation result,the distance between standing waves and the wedge transition line were obtained in experiment.Synthetical analysis of experimental results shows that there is a high agreement between hot wire anemometer and sublimation method.This indicates that flow state in a 3-D boundary layer can be measured conveniently by hot wire anemometer;that at a suitable angle,the hot wire anemometer support does not impact the measurement;that hot wire probe has less effect on flow in boundary layer.So the results measured by hot wire anemometer may be regarded as actual flow in boundary layer.Analysis of experimental data shows that the combination of hot wire anemometer and sublimation method is a very effective method.