In the present paper, a method for choosing the parameters of a wing-surface waviness intended for use on small aircraft is introduced. We propose choosing the waviness geometry based on the parameters of the boundary layer for the given regime of the flow around the classical wing installed at zero angle of attack, α = 0°. We propose to check the result of the choice of the waviness parameters by the change of the flow structure in the boundary layer of the wing. For the properly chosen waviness, the continuous separation zone characteristic of the classical wing should transform into local separation zones. To substantiate and verify the proposed method, we investigate the flow around two wing models, one model being a wavy wing with a rigid surface and the other, a wavy wing with a varioform surface characterized by variable hump height. The study was carried out at wing-chord-based Reynolds numbers Re ranging from 0.35·10⁵ to 1.410⁵ at α = 0°. Using oil-film visualization, a transition of local separation zones into a continuous separation zone on the rigid-surface wing model with a decrease of Reynolds number implemented by decreasing the flow velocity was revealed. By measuring the velocity profile in the boundary layer on the varioform wing, the transformation of the continuous separation zone into local separation zones yet at a constant velocity with a change in waviness height has been also demonstrated. It is experimentally shown that the formation of local separation zones is observed provided that the waviness height f is one order of magnitude greater than the displacement thickness σ_l in the boundary-layer pre-separation region, and the waviness coefficient K_w is greater than unity. A distinct formation of local separation zones is revealed by oil-film visualization at K_w = 2.8.

在本文中，介绍了一种选择用于小型飞机的机翼表面波纹度参数的方法。我们建议根据边界层的参数来选择波纹几何形状，该参数是针对安装在零迎角α= 0°的经典机翼周围流的给定状态的。我们建议通过机翼边界层中流动结构的变化来检查波纹度参数的选择结果。为了正确选择波纹度，经典机翼的连续分离区特性应转变为局部分离区。为了证实和验证所提出的方法，我们研究了两种机翼模型周围的流动，一种模型是具有刚性表面的波浪形机翼，另一种模型是具有变化的驼峰高度的具有可变曲面的波浪形机翼。α = 0°时为⁵至1.410 ⁵。使用油膜可视化，揭示了局部分离区域向刚性表面机翼模型上的连续分离区域的过渡，并通过降低流速实现了雷诺数的降低。通过测量变角形机翼边界层中的速度分布，还证明了连续分离区向局部分离区的转变，但仍保持恒定的速度，但波度高度却发生了变化。据实验表明，观察到的提供本地分离区的形成，所述波状起伏的高度˚F是量级大一个数量级比位移厚度σ_升在边界层预分离区域中，波纹系数K _w大于1。的局部分离区域A不同的形成是通过油膜可视化在揭示ķ_瓦特= 2.8。