Flow characteristics around a non-submerged vegetation patch: TELEMAC-2D, ANSYS, and experimental comparison

This study presents the first systematic comparison between TELEMAC-2D and ANSYS-FLUENT (2D) for simulating flow around a non-submerged vegetation which represented by rigid cylinders, and validated against laboratory experiments. Two vegetation representations are evaluated in TELEMAC-2D: a resistance-based formulation and a vegetation geometry is directly resolved on the computational grid. Model calibration is performed using measured velocity and water-depth data, and the performance is assessed through velocity fields, wake development, and turbulent kinetic energy. Both TELEMAC-2D approaches reproduce the overall flow structure; however, the geometric representation shows significantly better agreement with ANSYS-FLUENT and experiments, capturing sharper velocity gradients, stronger wake deficits, and more realistic turbulence distributions. The resistance-based approach overestimates wake velocities and smooths turbulence due to uniform drag application. ANSYS-FLUENT resolves stem-scale momentum losses but underestimates turbulence because of its two-dimensional formulation. The results highlight limitations of a resistance-based formulation modeling and provide guidance for improving simplified depth-averaged approaches.