ABSTRACT
The objective of this work is to investigate the effect of a novel active turbulence grid on the mixing of airflow in a wind tunnel. Our grid contains flexible tubes attached onto the intersections of a square biplane grid of hollow rectangular bars. Pressurized air led to the grid bars is applied to produce random motion of the tubes in order to increase the turbulence level of the flow downstream of the grid. Upstream of the grid, an electric heater was assembled in the centerline of the wind tunnel to create an inhomogeneous temperature field. This low turbulence intensity flow was then passed through the grid. By means of an infrared camera and a porous sheet, temperature-inhomogeneity of the flow was investigated downstream of the grid in the test section while varying parameters: distance from the grid, mean flow velocity, gauge pressure of pressurized air. It was found that the grid substantially enhances the mixing.
