NONE 20260224142242570 wseas/wseas content-registration-form+ja@crossref.org content-registration-form WSEAS TRANSACTIONS ON FLUID MECHANICS 1790-5087 2224-347X Nora Bensider Theoretical and Applied Fluid Mechanics Laboratory, Université des Sciences et de la Technologie Houari Boumediene USTHB, BP 32, 16111, USTHB, Algiers, ALGERIA Amina Mataoui Theoretical and Applied Fluid Mechanics Laboratory, Université des Sciences et de la Technologie Houari Boumediene USTHB, BP 32, 16111, USTHB, Algiers, ALGERIA Samira Hamaili Louaifi Theoretical and Applied Fluid Mechanics Laboratory, Université des Sciences et de la Technologie Houari Boumediene USTHB, BP 32, 16111, USTHB, Algiers, ALGERIA This paper proposes a numerical study of a turbulent flow around an inclined square obstacle in a channel. The objective of this work is to examine the effect of the obstacle inclination (θ) on the boundary layer separation. The two-dimensional unsteady Reynolds-averaged Navier-Stokes equations (2D-URANS) were solved by the finite volume method using the shear stress transport k- model ((SST-(k-ω)) for turbulence closure. Validation is carried out with available experimental data and large eddy simulation (LES) results of the no inclined case (θ=0∘). Six obstacle inclinations in the range 0∘ ≤θ≤45 ∘, for Reynolds number Re=3000, are examined. The results show that the Strouhal number (St) increases linearly until it reaches a maximum value (St = 0.145) for a critical angle (θ = 15°), then decreases below this value. 12 31 2025 12 31 2025 189 19 https://creativecommons.org/licenses/by/4.0/deed.en_US 10.37394/232013.2025.20.19 https://wseas.com/journals/fluids/2025/a385113-016(2025).pdf Martínez-Sánchez, Á., López, E., Le Clainche, S., Lozano-Durán, A., Srivastava, A., & Vinuesa, R. (2023). Causality analysis of large-scale structures in the flow around a wall-mounted square cylinder. 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