Unsteady lifting-line theory (ULLT) is a low-order method capable of modeling interacting unsteady and finite wing effects at low computational cost. Most formulations of the method assume inviscid flow and small amplitudes. Although these assumptions might be suitable for small-amplitude aeroelastic problems at high Reynolds numbers, modern engineering applications increasingly involve lower Reynolds numbers, large-amplitude kinematics, and vortex structures that lead to aerodynamic nonlinearities. This paper establishes that ULLT still provides a useful solution for low-Reynolds-number, large-amplitude kinematics problems, by comparing ULLT results against those of experimentally validated computational fluid dynamics simulations at $\mathit{Re}=\mathrm{10,000}$. Three-dimensional effects stabilize leading-edge vortex (LEV) structures, resulting in a good prediction of whole wing force coefficients by ULLT. Although the inviscid spanwise force distributions are accurate for small-amplitude kinematics, the ULLT cannot model three-dimensional vortical structures, and thus it cannot correctly predict the force distribution due to the LEV. It can, however, predict the shedding of LEVs to a limited extent via the leading-edge suction parameter criterion. This can then be used as an indicator of the usefulness of the force distribution results.

非定常升力线理论 (ULLT) 是一种低阶方法，能够以低计算成本模拟非定常和有限翼效应的相互作用。该方法的大多数公式都假设无粘性流动和小振幅。尽管这些假设可能适用于高雷诺数下的小振幅气动弹性问题，但现代工程应用越来越多地涉及低雷诺数、大振幅运动学和导致空气动力学非线性的涡流结构。本文通过将 ULLT 结果与在$\mathit{关于}=\mathrm{10,000}$. 三维效应稳定了前缘涡 (LEV) 结构，从而使 ULLT 能够很好地预测整个机翼力系数。尽管无粘性展向力分布对于小振幅运动学是准确的，但 ULLT 无法模拟三维涡结构，因此无法正确预测 LEV 引起的力分布。然而，它可以通过前沿吸力参数标准在有限的范围内预测 LEV 的脱落。然后，这可以用作力分布结果有用性的指标。