DESIGN, CONSTRUCTION AND TESTING OF A LOW-SPEED WIND TUNNEL

The increase in wind energy over the last decade has depicted a significant development in onshore and offshore wind turbine designs. Wind turbine designs are highly dependent on aerodynamic properties of lift and drag. There is normally an iterative process consisting of numerical design, prototype construction, testing and optimisation, calibration of computational flow models on the path to commercialisation. Theoretical turbine models are usually validated or optimised by the assessment of scaled models tested in a wind tunnel. The aim of this paper was to design and manufacture a small-scale low-speed wind tunnel for the testing and optimisation of novel wind turbines. An open circuit design was chosen instead of a closed system to save space. The wind tunnel was to achieve maximum flow speeds of 9m/s in alignment to average wind speeds located off the South African coastline as investigated in previous studies. The conditions within the testing area of the design were required to maintain steady flow conditions. A hot wire wind anemometer was used to measure the flow speeds at different points of the wind tunnel for the validation of the design. The results showed that each section of the wind tunnel complied to the design conditions with minimum error. The turbulence intensity was also investigated and depicted across the circuit. The results have shown that the design philosophy which was chosen was sound and the system may be pursued for the testing of novel scaled wind turbines and scaled aerodynamic profiles for validation and optimisation purposes.