Title: Adjoint-Assisted Topology-Optimization-Inspired Analysis of Pseudo-Porous Flow Fields: Application to a Flettner Rotor Show Chinese title

Title: 伴随辅助的基于拓扑优化的拟孔隙流场分析：应用于弗莱特纳旋翼

Abstract: This paper presents an adjoint-assisted, topology-optimization-inspired approach for analyzing topological sensitivities in fluid domains based on porous media formulations -- without directly utilizing the porosity field as a design variable. Instead, the method evaluates the sensitivity with respect to the porosity parameter via an indirect, adjoint formulation, enabling intuitive visualization of cost-functional improving or deteriorating regions. These sensitivity fields are not used in a classical optimization loop but rather to qualitatively assess spatial areas that indicate potential for flow improvement. A key benefit of the proposed approach is its non-intrusive nature: no modifications to existing adjoint solvers, e.g., for shape optimization purposes, are required. As such, the method can be interpreted as an alternative post-processing step that supports early-stage design insights. The approach is demonstrated on a Flettner rotor operating in atmospheric wind at a diameter-based Reynolds number and spinning ratio of ReD=2E+06 as well as k=3 to highlight its practical relevance and interpretability. Placing a container stack in cost-functional improving or deteriorating areas validates the method's prediction quality of topological flow sensitivities. Show Chinese abstract

Abstract: 本文提出了一种伴随方法辅助的、基于拓扑优化思想的方法，用于分析流体域中的拓扑灵敏度，基于多孔介质公式——而不直接利用孔隙率场作为设计变量。相反，该方法通过间接的伴随公式评估相对于孔隙率参数的灵敏度，从而实现改善或恶化的成本泛函区域的直观可视化。这些灵敏度场不用于经典的优化循环，而是用来定性评估可能改进流动的空间区域。所提出方法的一个关键优势是非侵入性的：不需要对现有的伴随求解器（例如用于形状优化目的）进行修改。因此，该方法可以被看作是一种替代的后处理步骤，支持早期设计洞察。该方法在一个基于直径的雷诺数ReD=2E+06和旋涡比k=3的Flettner转子上运行于大气风中进行了演示，以突出其实用性和可解释性。将集装箱堆放在改善或恶化成本泛函的区域验证了该方法对拓扑流动灵敏度预测的质量。