Xuan-Thuc Nguyen1, Ngoc-Quynh Nguyen1, Le-Minh Nguyen1, Thi-Tuyet-Nhung Le2, Dai-Cuong Pham2, and Dinh-Quy Vu2
1Viettel High Technology Industries Corporation– Viettel Group, Hanoi, Vietnam
2School of Mechanical Engineering, Hanoi University of Science and Technology, Hanoi, Vietnam
Received: March 07, 2026
Accepted: July 11, 2026
Publication Date: August 05, 2026
Composite wing model.
Copyright The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.
Download Citation: BibTeX | http://dx.doi.org/10.6180/jase.202611_34.009
Fluid–Structure Interaction (FSI) is a multidisciplinary research field that has drawn significant attention across various domains, including aerospace, biomedical engineering, agriculture, industry, and renewable energy. The finite element method (FEM) has become a leading computational tool for investigating these coupled phenomena, enabling more accurate prediction of the interactions between fluids and solids. Although numerical FSI simulations are more economical than physical experiments, they require substantial computational resources. This study focuses on the influence of time step size on the accuracy and convergence of coupled FSI simulations. A cantilever beam model is adopted as the benchmark case and analyzed using the ANSYS software suite. The time step of the fluid solver and the sub-step size of the structural solver are systematically varied to determine the optimal configuration that ensures accuracy while minimizing computation time. The amplitude and frequency responses obtained from the coupled solver are validated against reference results from published literature. The optimized time step and sub-step selection strategy is then applied to more
complex FSI simulations, including a cropped delta wing and a lightweight composite UAV wing, to evaluate flutter behavior within their operating envelopes.
Keywords: Computational Fluid Dynamics (CFD); Fluid–Structure Interaction (FSI); Time Step, Sub-Step; Convergence
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