Numerical Investigation of Oblique Shock Attachment, Stand-Off Distance and Shock Thickness over a 25°Wedge

Abstract

: This work presents a computational study of oblique shock behavior over a fixed 25° wedge for supersonic free-stream Mach numbers M∞=2, 3, 4. Two-dimensional viscous simulations were performed with ANSYS Fluent (density-based solver, SST k −ω turbulence model, energy equation on) on a fine unstructured triangular mesh with prism inflation near the wedge. For M∞=2 the shock detaches producing a bow shock with measured stand-off distance δ≈6.26×10−4 m. For M∞=3 and the oblique shock attaches at the wedge apex. Shock angles were measured from Mach contours and validated against the analytical θ–β–M relation; percent differences are small (≈0.8–0.9%). Shock thicknesses were quantified from density and density-gradient line profiles (reported values from simulation notes: M2 ≈ 0.32 mm, M3 ≈ 0.25 mm, M4 ≈ 0.20 mm), showing a clear decrease with increasing Mach number. Detailed methodology, mesh statistics, theory comparison, and uncertainty estimates are provided. Future work will extend the parametric study to wedge angle variation, Reynolds number effects and experimental validation.