发表机构
University of California, Davis（加州大学戴维斯分校）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出统一线性理论，研究可压缩亚声速流中有限弦长多孔翼型的非定常载荷，发现渗透性控制载荷对可压缩性的敏感性，并指出不可压缩与可压缩理论组合会误判多孔载荷比。
AI 中文摘要
本文发展了一种统一线性理论，用于计算可压缩亚声速流中有限弦长翼型（刚性或多孔）的非定常载荷。该公式将Possio积分算子与对流渗透边界条件相结合，允许弦向变化的导纳，同时保留尾迹和非定常Kutta条件。翼型边缘和导纳不连续处的载荷指数在局部渗透参数方面保持其不可压缩形式，因此加权-雅可比配点法得以沿用。该解与已发表的不可压缩结果及独立的可压缩公式进行了验证。阵风和沉浮响应及其阶跃对应物表明，渗透性控制着非定常载荷对可压缩性的敏感性。随着渗透性增加，材料阻抗而非周围流动决定压力跃变，但这是渐进的：在马赫数0.7时，弱渗透表面上的阵风载荷变化了三分之一到二分之一，而电阻性表面的封闭形式稳态和高频极限表明，只有当渗透参数大大超过马赫数时，载荷才消失。多孔与不可渗透载荷比（用于评判处理效果）无法通过结合不可压缩多孔理论和可压缩刚性理论获得，后者对此比值的误判可达两倍。不可压缩理论对声学紧凑弦高估了该比值，对非紧凑弦则低估了该比值，在马赫数0.5至0.7和约化频率5至20范围内，误差因子为1.4至4.3，从而夸大了载荷减小效果。由于紧凑性取决于马赫数乘以约化频率，该误差在低速时依然存在，在马赫数0.05且约化频率高于10时，误差超过10%。
英文摘要
A unified linear theory is developed for the unsteady loading of finite-chord aerofoils, rigid or porous, in compressible subsonic flow. The formulation combines Possio's integral operator with a convective permeable boundary condition, allowing chordwise-varying admittance while retaining the wake and unsteady Kutta condition. The loading exponents at aerofoil edges and admittance discontinuities keep their incompressible form in terms of the local permeability parameter, so weighted-Jacobi collocation carries over. The solution is verified against published incompressible results and an independent compressible formulation. Gust and heave responses and their indicial counterparts reveal that permeability controls the sensitivity of unsteady loading to compressibility. As permeability increases, the material impedance rather than the surrounding flow sets the pressure jump, but only gradually: at Mach number 0.7 the gust load on a weakly permeable surface changes by a third to a half, and closed-form steady and high-frequency limits for resistive surfaces show that it vanishes only when the permeability parameter greatly exceeds the Mach number. The porous-to-impermeable load ratio, by which a treatment is judged, cannot be obtained by combining incompressible porous and compressible rigid theories, which misjudge it by up to a factor of two. Incompressible theory overestimates this ratio for an acoustically compact chord and underestimates it for a non-compact one, by factors of 1.4 to 4.3 at Mach numbers 0.5 to 0.7 and reduced frequencies 5 to 20, overstating the load reduction. Since compactness depends on Mach number times reduced frequency, the error persists at low speed, exceeding 10 per cent at Mach number 0.05 for reduced frequencies above 10.
