Flow around triangular prisms with varying vertex angle at low Reynolds numbers.

This article investigates the unsteady, laminar flow around isosceles triangular prisms with vertex angles of 30°, 45°, 60°, and 90° at Reynolds numbers (Re) between 50 and 150 using numerical simulations via the open-source OpenFOAM code. The study analyzes wake characteristics—including velocity, vorticity, enstrophy (a measure of rotational kinetic energy dissipation), and vortex shedding patterns—and quantifies fluid dynamic forces through drag and lift coefficients and Strouhal numbers. Results show that increasing the vertex angle enhances bluffness, leading to higher drag coefficients, wider wakes with more mixing, and distinct bifurcation of vortical structures in the far wake; the shedding frequency increases linearly with Reynolds number for all prisms. Comparisons with prior studies on square cylinders and 45° oriented square cylinders highlight differences in wake behavior and force coefficients, providing insights relevant to engineering applications such as building aerodynamics, energy harvesting, and heat exchanger design.