Qualitative and Quantitative Investigation of Honeycomb and Screens Effect in Improvement of Flow Characteristics in a Subsonic Wind Tunnel

Wind tunnels generate controlled air flow which passes through the model. Thus، a series of useful data related to air flow quality are obtained. The final goal of wind tunnel design is to generate a uniform air flow with minimum turbulence intensity and low flow angle. One of the methods for decreasing the turbulence intensity is to install honeycomb and screens in the settling chamber of the wind tunnel. In this research، the effects of honeycomb and screens with specified geometric parameters on velocity distribution، turbulence intensity، skewness and flatness are investigated. A set of hot-wire anemometer is used to measure turbulence intensities. It measures flow instantaneous velocity with high frequency. The results show that the installation of honeycomb and screens، and isolation of the test section from the fan decreases the turbulence intensity of the test section about 75% and، optimizes the skewness and flatness values. Moreover، normal probability distribution of instantaneous velocity approaches the normal distribution.