Turbulence generated by a wind tunnel of multi-fan type in uniformly active and quasi-grid modes

In an attempt to simulate atmospheric turbulence at high-Reynolds numbers, an innovative wind tunnel of “multi-fan type” is developed. The airflow is driven by an array of fans (9 columns ×× 11 rows), each of which is independently controlled by a computer. A driving mode (“uniformly active mode”) is applied, which has been typically used for turbulence modeling using a smaller wind tunnel. Another mode with grid-like distributed fans that are driven steadily (“quasi-grid mode”) is introduced and found to produce turbulence characteristics similar to the conventional grid turbulence. Comparison of turbulence characteristics of the two modes reveals the turbulence structure of the uniformly active mode.