小型无人机悬停与巡航阶段的翼-旋翼气动相互作用
Wing-Rotor Aerodynamic Interactions in Small UAVs During Hover and Cruise
AI总结：
本研究采用基于非稳态雷诺平均纳维-斯托克斯方程的计算框架，探究小型无人机悬停与巡航阶段的翼-旋翼气动相互作用，明确了前进比、螺旋桨转速等因素对气动性能的影响规律。
AI中文摘要：
紧凑型垂直起降无人机需采用相同的倾转旋翼构型来完成两项截然不同的气动任务：维持悬停状态和实现高效巡航。本研究采用经验证的基于非稳态雷诺平均纳维-斯托克斯方程的计算框架，探究两种运行工况下潜在的翼-旋翼相互作用。对于巡航工况，前进比决定了推力产生、推进效率与尾流连贯性之间的平衡；较低的前进比会产生紧密缠绕的 slipstream（ slipstream 译为滑流），该滑流会经历强烈的涡旋相互作用、跳跃式运动以及早期尾流分叉；在较高前进比下，滑流保持更窄、更连贯的射流状结构，这既提高了推进效率，又降低了螺旋桨推力和机翼升力。机翼处的流动冲击通过接近、相互作用和对流阶段来表征，揭示了涡旋拉伸、尾流分叉、阻塞效应、镜像诱导速度以及流向动量对流对下游尾流的综合影响。在悬停工况下，螺旋桨的转速对整体气动性能的影响远大于机翼的位置；尽管机翼相对于螺旋桨的位置会改变局部尾流相互作用及其前缘处的流动冲击，但对总推力系数和品质因数的影响仍有限；本研究还阐释了围绕螺旋桨和机翼的涡旋与尾流动力学，这些动力学是决定上述气动性能的关键因素。
英文摘要：
A compact vertical take-off and landing aircraft requires the same tilt-rotor configuration to perform two fundamentally different aerodynamic tasks: sustain hover and deliver efficient cruise. This work investigates the underlying wing-rotor interactions in both operating regimes using a validated unsteady Reynolds-averaged Navier-Stokes equations-based computational framework. For cruise, the advance ratio governs the balance between thrust production, propulsive efficiency, and wake coherence. Lower advance ratios produce a tightly wound slipstream that undergoes strong vortex interactions, leapfrogging, and early wake bifurcation. At higher advance ratios, the slipstream retains a narrower and more coherent jet-like structure, improving propulsive efficiency while reducing both thrust of the propellor and lift of the wing. The flow impingement at the wing is characterized through the approaching, interaction, and convection phases, revealing the combined influence of vortex stretching, wake bifurcation, blockage, image-induced velocity, and streamwise momentum convection on the downstream wake. In hover, the propeller's rotational speed governs the overall aerodynamic performance more strongly than the wing's placement. Although the position of the wing with respect to the propellor modifies the local wake interactions and flow impingement on its leading edge, its influence on the integrated thrust coefficient and figure of merit remains limited. We also explain the vortex and wake dynamics around the propellor and the wing responsible for governing these aerodynamic performance.
