Experimental Study on Turbulent Characteristics of Swirling Flow in 90 $^{\circ}$ Degree Circular Tube by Using a PIV Technique

An experimental investigation was performed to study the turbulent characteristics of swirling flow a 90 circular tube for Re = 10,000, 15,000 and 20,000. 2D-PIV(Particle Image Velocimetry)technique was employed to measure the fluctuation velocity field. The results include spatial distributions of mean velocity vectors, turbulence intensity and turbulence kinetic energy. The axial and radial turbulence intensities, and kinetic energy profiles show double-peak structures in the inlet region of the 90 degree bend and the profiles are disappeared along the test tube with decaying the swirl intensity.