Dynamics of the jet flow issued from a lobed Nozzle: Tomographic particle image velocimetry measurements

This study focuses on the dynamics of three-dimensional jet flow issued from a lobed nozzle. Flow field measurements were performed using split-screen dual-camera tomographic particle image velocimetry (tomo-PIV) system. The nozzle was constructed three-circle configuration at exit, where ratio circular centre offset to circle radius a/b=0.8. Two high-speed cameras used with an appropriate combination prismatic and planar mirrors split each camera into two views. Reynolds number fixed Re=2400, same also measured for comparison. Fourier mode decomposition identify large-scale structures superposed in unsteady field. lobe trough decreased jet’s width due smooth connection between pipe section exit. Turbulence intensified shear layer, passing fluid puffs instantaneous broken jet. successively observed be axisymmetric structure modes dominating St=0.39. However, breakdown induced by St=0.51 0.65, double helical arose St=0.28 0.38 (also 0.4) layer potential core interacted entire column.