基于三维粗糙元的新型边界层转捩控制技术研究

三维离散型粗糙元是一种具有广阔应用前景的新型边界层转捩诱导与控制技术。针对二维粗糙带转捩位置滞后、难以控制横流转捩的固有缺陷，提出了一种基于三维离散型粗糙元的新型边界层转捩技术。理论估算了离散型粗糙元的外形参数，研制成功了固化快、易于成型且附着力强的粗糙元配方及高精度制作工艺。选用二维翼型和三维组合体模型，采用测压、测力、升华法和红外成像法，风洞实验验证了离散型粗糙带的转捩和附加阻力特性。通过数值计算研究了粗糙元的尺度效应，获得了粗糙元直径d、高度k和间距l对其转捩特性的影响规律。研究结果表明，该新型离散型粗糙带附加阻力小，转捩位置准确，性能可靠、稳定。该文所得成果为固定转捩风洞实验与层流控制创建了一种新的技术手段，同时也为进一步开展离散型粗糙元的转捩机理研究提供了参考依据。

RESEARCH ON A NEW TRANSITION CONTROL TECHNOLOGY BASED ON THREE-DIMENSIONAL ELEMENTS

Three-dimensional discrete roughness, with a wide application prospect, will become a new type of boundary layer transition induction and control technology. To eliminate the transition position lag and cross-flow transition difficulty for 2-D roughness, a new fixed transition technology based on discrete roughness elements has been developed. The shape parameters of roughness elements of rough spots are calculated. A fast curing, easy molding, grinding and difficult deformation formula is presented and the high precision manufacturing technology for discrete roughness elements is established. Using 2-D airfoil and 3-D wing-body combination models, through pressure and force test, sublimation and infrared imaging methods, the transition and additional drag characteristics are verified by wind tunnel tests. The scale effect of diameter d, height k and spacing l of the elements on the transition characteristics is studied by numerical simulation. The results show that the new discrete roughness has the advantages of a small additional drag, high transition location accuracy and reliable performance. The accomplishment of this project provides a new way for fixed transition wind tunnel experiment and important reference for the further transition mechanism research.