A reduced-order model (ROM) is proposed for efficient drag prediction on a streamlined body with surface imperfections that emulate leading-edge roughness or erosion-induced damage. Surface imperfections are idealised as forward-facing step(s) for which the chordwise position, spanwise length, and distribution of steps are varied. It is hypothesised that superposed a bilinear dependencies on the chordwise location and spanwise length of individual steps comprising the damage provide for reasonable ROM predictions of the corresponding change in total drag on the streamlined body. Direct numerical simulations are applied to test the ROM hypotheses and to study interactions between the three-dimensional steps and the separated near-wall turbulent flow fields, justifying the underlying terms and form of the ROM. Insights into the flow physics influencing both form and friction contributions to total drag are revealed, and satisfactory model performance is demonstrated for complex damage idealisations that emulate fracture of laminated wind turbine blades.

提出了一种降阶模型 (ROM)，用于对具有模拟前沿粗糙度或侵蚀引起的损坏的表面缺陷的流线型体进行有效的阻力预测。表面缺陷被理想化为朝前的台阶，其弦向位置、展向长度和台阶分布是变化的。假设在包含损坏的单个台阶的弦向位置和展向长度上叠加双线性相关性，为流线型车身上总阻力的相应变化提供了合理的 ROM 预测。直接数值模拟用于测试 ROM 假设并研究三维台阶与分离的近壁湍流流场之间的相互作用，证明 ROM 的基本术语和形式是合理的。