Effects of Roughness Ribs on Flow Patterns of Simplified Aircraft Model

The dye-injection flow visualization technique has been used to study the flow patterns of a simplified aircraft model, the effects of side roughness ribs and "O" type with side roughness ribs on the flow patterns have been observed in details. The experimental results indicated that the range of the angle of attack influenced by the Reynolds number in the pitching moment curves is related to the angle of attack at which the nose vortex begins to beat the canopy until it mixes in the front of the canopy. In this water tunnel experiments, the results obtained at 20cm/s for the roughness height 0.8mm can be used to explained the scatter of the pitching moment curves obtained in the wind tunnel measurements.