Realization of a large-scale turbulence field in a small wind tunnel

An active turbulence generator was developed to generate a large-scale turbulence having large turbulence Reynolds numbers, Rl and Rλ, in a small wind tunnel. The statistical quantities were measured in the resultant homogeneous and quasi-isotropic turbulence. High turbulence intensities and large integral scales were attained in it. The energy spectrum had a wide inertial subrange of about two orders of magnitude in wavenumber. The width of the inertial subrange approached to that obtained for the grid turbulence having a far larger mesh Reynolds number of RM= 2.4×106. Intermittency of fine-scale turbulent eddies was observed in the waveform of the velocity derivative.