Michalski, H.Mattner, T.Balasuriya, S.Binder, B.2025-07-092025-07-092025Theoretical and Computational Fluid Dynamics, 2025; 39(2):23-1-23-230935-49641432-2250https://hdl.handle.net/2440/145798Two-dimensional open channel flow past a rectangular disturbance in the channel bottom is considered in the case of supercritical flow, where the dimensionless flow rate is greater than unity. The response of the free surface to the height and length of a rectangular disturbance is investigated using the forced Korteweg–de Vries model of Michalski et al. (Theor Comput Fluid Dyn 38:511–530, 2024). A rich and complex structure of solutions is found as the length of the disturbance increases, especially in the case of a negative disturbance. As the length of the disturbance is decreased, some solutions approach those of the well-studied point forcing approximation, but there are other solutions, for a negative disturbance, that are not predicted by the point forcing model. The stability of steady solutions is then considered numerically with established pseudospectral methods.en© TheAuthor(s) 2025. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.free-surface flow; Korteweg–de Vries equation; open channel flow; supercriticalJournal article10.1007/s00162-025-00735-3733903Michalski, H. [0000-0002-2415-6371]Mattner, T. [0000-0002-5313-5887]Balasuriya, S. [0000-0002-3261-7940]Binder, B. [0000-0002-1812-6715]