INFLUENCE OF WING SHAPES ON SURFACE PRESSURE-FLUCTUATIONS AT WING-BODY JUNCTIONS

The body surface pressure fluctuations along the stagnation streamlines of several wing-body junctions were measured with microphones. The wing shapes are of a 3:2 semielliptical-nosed NACA-0020-tailed body, a parallel centerbody model, a tear drop shape, Sand 1850, NACA-0015, and NACA-0012. The oil-flow visualizations revealed the limiting streamline structure on the wall where the models were mounted. Measurements were conducted at a nominal reference velocity of 32.5 m/s and Reynolds number based on approach momentum thickness of 4450. Pressure-fluctuation measurements at the nose region show the existence of the bimodal pressure-fluctuation histograms and oil-flow visualization pictures show the primary separation regions, line of low shear, and the fish-tail-shaped wake region. The measurements show that the pressure fluctuations and the primary separation line location at the nose highly differ depending on the nose geometry. The histograms of the pressure-fluctuation data show that the fluctuations are different than Gaussian. A simple physical relationship between the pressure fluctuations and the body geometry is given.