Wind tunnel experimental study of the grille-generated turbulence in the short test section

The objective of the current work is to modulate the local high turbulent field behind grilles through a wind tunnel with a short axial distance. The flow fields formed by five types of grilles (two mesh grilles and three vertical bar grilles, 3 cm × 3 cm sectional aluminum profiles assembly) were experimentally tested by the hot-wire anemometer. The turbulent parameters distribution and isotropic characteristics of the turbulent flows near behind the grilles are obtained. Besides, the fitting formulas for turbulent flows are acquired according to the changing law of parameters, and the goodness of the fitting is 0.96. Meanwhile, the classic spectrum estimation and modern spectrum estimation are adopted to analyze the turbulent power spectrum density (PSD), respectively. It is noted that different spectral estimators can accurately predict the turbulent PSD at the near-field region, and the deviations exist only at low frequencies. Besides, by adjusting the distance between the grilles and the measuring point, the wind speed, and the grille structure, the energy structure behind the grille turbulent field can be changed.