Effects from turbulence levels created by a three-cylinder rotating system on the flow over a dimpled surface of an airfoil are reported. The three-cylinder rotating system effect is tested on the flow over a NACA0015 with leading-edge dimples at various angles of attack at Reynolds numbers of 0.5 × 10⁵ and 1.0 × 10⁵ in a low-speed wind tunnel. To the effect of mimicking free-stream flow perturbations, the three-cylinder system had small dimensional characteristics compared to those of the airfoil. Two-dimensional (2D) Particle Image Velocimetry (PIV) was used to characterize the flow with illumination from a dual-head Nd:YAG laser and imaging from two high-resolution PIV cameras setup to capture details of the three-cylinder system and the airfoil flow simultaneously. Results show wake characteristics that create complex unsteady and turbulent flows of various intensities as they rotate at various speeds in the free-stream. These free-stream flow disturbances establish the unsteady and turbulent flows that interact with the airfoil flow. The study finds substantial effects occurring for certain cylinder-system settings, airfoil angle-of-attack, and Re number, notably detecting a diminishing separation region and a decrease in its turbulence levels when compared to those for the flow without turbulence generated in the free stream.

报道了由三缸旋转系统产生的湍流水平对翼型件凹坑表面上的流动的影响。三缸旋转系统的作用是在NACA0015上的流动上进行测试的，该流动具有前沿凹坑，在不同的迎角下，雷诺数分别为0.5×10 ⁵和1.0×10 ⁵在低速风洞中 为了模仿自由流的扰动，与翼型相比，三缸系统的尺寸特性小。二维（2D）粒子图像测速（PIV）用于通过双头Nd：YAG激光器的照明和两个高分辨率PIV摄像机的成像来表征流动，以捕获三缸系统和翼型同时流动。结果表明，尾流特性会在自由流中以不同的速度旋转时，产生各种强度的复杂的不稳定和湍流。这些自由流的扰动建立了与翼型流相互作用的不稳定和湍流。研究发现，某些气缸系统设置，机翼攻角和Re数会产生重大影响，