Flow measurement in a wind tunnel with blockage screens.

The small and medium-scale wind turbine development have been improved due to their adaptability in offshore and onshore localities for wind farm applications. Blockage effects caused by numerous impediments restrict the flow-field near the turbine and impact the turbine's performance. The testing and optimization of turbines in such conditions at laboratory-level are challenging due to the unavailability of customized wind tunnel configurations with blockage screens. The present work focuses on the design, development and evaluating aerodynamic performance of wind tunnel with and without blockage screens. A comprehensive design is established by evaluating losses in each section, uncertainties, velocity, forces, and turbulence intensity in the wind tunnel through the experimental analysis. The novel blockage screens are arranged to maintain 5 % and 10 % blockage percentage for wind velocity range of 2–14 m/s. The maximum velocity reduction with 5 % blockage is 41.40 % and this drop reaches to 67.84 % for 10 % blockage. Consequently, available wind power is seen to undergo a maximum reduction of 79.88 % and 96.67 %, respectively. • Design and development of a subsonic open-loop wind tunnel with a novel blockage screen for performance analysis in a skewed flow environment. • Detailed calibration, uncertainty, and losses analysis to quantify the accuracy of the measurements. • Flow investigation with different blockage percentages (5 % and 10 %) inside the wind tunnel. • The maximum velocity reduction with 5 % blockage is 41.40 % and this drop reaches to 67.84 % for 10 % blockage. [ABSTRACT FROM AUTHOR]