Aerodynamics and aeroacoustics of a 2-bladed Darrieus VAWT are investigated at a chord-based Reynolds number of 1.5 × 10 5. Four tip speed ratios (TSRs), 0.37, 1.12, 2.23, and 2.97, are simulated at a freestream velocity of 5.07 m/sec, reflecting an experimental campaign to validate the numerical findings. High-fidelity CFD is performed via a Lattice Boltzmann/Very Large Eddy Simulation (LB-VLES) approach, while the Ffowcs Williams–Hawkings (FW-H) analogy is used for far-field noise predictions, both implemented in the commercial software 3DS SIMULIA PowerFLOW 6-2020. Using Richardson Extrapolation method, thrust, lateral force, and overall sound pressure level (OSPL) exhibit stronger grid convergence (grid convergence index of 0.015%, 2.2%, and 0%, respectively) compared to torque (9.02%). Grid convergence is also optimal at a TSR of 2.23 compared to 1.12 and 2.97, with GCI values of 0.015% versus 1.501% and 0.104%, respectively. The blades in the downwind half consistently produce less thrust and torque than the upwind half due to intensified blade–wake interactions, with the upwind-to-downwind thrust ratio growing from 1.3 at TSR=0.37 to 17.6 at TSR=2.97. Noise increases across the whole frequency range as TSR rises, largely driven by higher unsteady loading.

Aerodynamics and aeroacoustics of a 2-bladed vertical axis wind turbine operating at a chord-based Reynolds number of 1.5 × 10 5 are examined. Four tip speed ratios (TSRs) are considered (0.37, 1.12, 2.23, and 2.97), all at a fixed freestream velocity of 5.07 m/sec. Commercial software 3DS SIMULIA PowerFLOW, employing a Lattice Boltzmann/Very Large Eddy Simulation approach, is used to perform high-fidelity CFD simulation. Far-field noise levels are obtained via the Ffowcs Williams–Hawkings acoustic analogy. Using Richardson extrapolation to compute grid convergence indices (GCI), thrust, lateral force, and overall sound pressure level (OSPL) display better convergence (GCI of 0.015%, 2.2%, and 0%, respectively) than torque (9.02%). Convergence improves at TSR=2.23 compared to 1.12 and 2.97 (GCI as low as 0.015% versus 1.501% and 0.104%). Upwind-to-downwind thrust ratios increase from 1.3 at TSR=0.37 to 17.6 at TSR=2.97, driven by intensified blade–wake interactions at higher TSRs. The unsteady loading that arises at these conditions also elevates noise levels, particularly near the most upstream azimuth sector (90 ◦ - 120 ◦), where blade loading peaks in a single rotation.