DEVELOPMENT OF A 2-DIMENSIONAL TURBULENT WAKE IN A CURVED CHANNEL WITH A POSITIVE STREAMWISE PRESSURE-GRADIENT

The development of turbomachinery wake flows is greatly influenced by streamline curvature and streamwise pressure gradient. This paper is p art of a comprehensive experimental and theoretical study on the devel opment of the steady and periodic unsteady turbulent wakes in curved c hannels at different streamwise pressure gradients. This paper reports on the experimental investigation of the two-dimensional wake behind a stationary circular cylinder in a curved channel at positive streamw ise pressure gradient. Measurements of mean velocity and Reynolds stre ss components are carried out using a X-hot-film probe. The measured q uantities obtained in probe coordinates are transformed to a curviline ar coordinate system along the wake center line and are presented in s imilarity coordinates. The results show strong asymmetry in velocity a nd Reynolds stress components. The Reynolds stress components have hig her values at the inner half of the wake than at the outer half of the wake. However, the mean velocity defect profiles in similarity coordi nates are almost symmetric and follow the same Gaussian function for t he straight wake data. A comparison with the wake development in a cur ved channel at zero streamwise pressure gradient suggests the decay ra te of velocity defect is slower and the growth of wake width is faster for a positive streamwise pressure gradient.