Acta Mech 231, 3755–3777 (2020) https://doi.org/10.1007/s00707-020-02716-5 ORIGINAL PAPER Xuzhi Du · Anning Wei · Yuhao Fang · Zhigang Yang · Daniel Wei · Chao-Hsin Lin · Zheyan Jin The effect of bend angle on pressure drop and flow behavior in a corrugated duct Received: 14 February 2020 / Revised: 21 April 2020 / Published online: 28 June 2020 © Springer-Verlag GmbH Austria, part of Springer Nature 2020 Abstract In the present study, the effect of bend angle on pressure drop and flow behavior in a small-diameter corrugated duct is numerically investigated and experimentally validated under a fully developed flow condi- tion. The large eddy simulation, together with the proper orthogonal decomposition (POD) method, is employed to study the pressure drop, mean flow pattern, and unsteady flow evolution for a corrugated duct with various bend angles. The results show that the pressure drop exhibits a monotonic increase with increasing bend angle. Specifically, as the bend angle increases from 0 ◦ to 90 ◦ , the pressure drop of the corrugated duct experiences a striking increase of about 43%. Accordingly, a larger bend angle is found to induce the occurrence of stronger Dean cells or larger swirl intensity downstream the duct bend. Meanwhile, as for larger bend angles, the main turbulent properties of the Dean cells could be, to some extent, governed by the first few POD modes, which appear to be featured with one or a few large-scale vortices. Generally, the larger bend angle causes stronger Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00707-020-02716-5) contains supplementary material, which is available to authorized users. X. Du · Y. Fang · Z. Yang · Z. Jin (B ) Shanghai Automotive Wind Tunnel Center, Tongji University, Shanghai 201804, China E-mail: zheyanjin@tongji.edu.cn X. Du E-mail: 2013xuzhi_du@tongji.edu.cn X. Du · Y. Fang · Z. Yang · Z. Jin Shanghai Key Lab of Vehicle Aerodynamics and Vehicle Thermal Management Systems, Shanghai 201804, China A. Wei · Z. Jin School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai 200092, China Z. Yang Beijing Aeronautical Science and Technology Research Institute, Beijing 102211, China D. Wei Boeing Research & Technology - China, Beijing 100027, China C.-H. Lin Boeing Commercial Airplanes, Seattle, WA 98124, USA Z. Jin Key Laboratory of Icing and Anti/De-icing of Aircraft, China Aerodynamics Research and Development Center, Mianyang 621000, Sichuan, China