The axial and lateral turbulence are reduced and smooth flow of air entering the test section is achieved by installing the honeycomb and screens for most efficiency and efficiencies of the air inlet. The ratio of length to wall size of the honey comb is maintained as per the recommended standards. The wire mesh is also fixed to smoother the flow further. This is particularly, useful for obtaining laminar flow. The duct is secured to the test section by flange. The provision is also made for easy removal of diffuser and diffuser for possible separation from the test section, when required. It is also highly smothered and painted.