Climate change motivates the transition from fossil fuels to low-carbon energy sources,and wind power is a key option. Among wind-energy technologies, vertical-axiswind turbines (VAWTs) offer advantages for offshore and urban applications dueto their omnidirectional wind acceptance and simpler structural requirements.In offshore floating platforms, the motion of the structure can induce periodicvariations in the apparent wind velocity, which may influence turbineperformance. This thesis also investigates whether such periodic (sinusoidal)wind velocities can alter the energy production of VAWTs, and examines theinfluence of the tip-speed ratio (λ), the dimensionless wind velocity amplitude(A∗), and the dimensionless wind-velocityfrequency (ω∗) on these effects, without seeking their optimization. The work followsthree stages: (1) characterization of the wind-tunnel test section, (2) designand construction of a single-bladed H-Darrieus VAWT with adjustable solidity,and (3) wind-tunnel experiments under steady and sinusoidal inflow conditions.Because the tunnel could not reliably reproduce the desired sinusoidalprofiles, a hexapod was used to oscillate the turbine and simulate unsteadyinflow. Measurements show that periodic inflow induces phase-dependent bladeloading and subtle torque fluctuations, but produces no statisticallysignificant increase in period-averaged power. Efficiency re mained primarilycontrolled by λ, with only minor, inconclusive deviations near peak operatingconditions due to ω∗. Recommendations include utilizing alow-turbulence-intensity wind tunnel, employing precision-aligned bearings, andconducting tests at higher tip speed ratios (λ > 3.0) to better resolve potentialunsteady effects.