Effect of Wind-Tunnel Contraction on Free-Stream Turbulence

The effect of wind-tunnel contraction on free-stream turbulence is determined by passing a well-defined turbulence through three contractions of ratios 4 : 1 , 9 :1 , and 16:1. Turbulent velocity measurements show that, in absolute magnitudes, the longitudinal component decreases and the lateral component increases as the flow accelerates through the contraction. Postand precontraction spectra are measured to get an idea about the distortion of turbulence structure.