Experimental study of turbulent cross-flow in a staggered tube bundle using particle image velocimetry

An experimental investigation was performed on turbulent cross-flow in a staggered tube bundle with transverse and longitudinal pitch-to-diameter ratios of 3.8 and 2.1, respectively. A particle image velocimetry technique was employed to obtain detailed measurements in the bundle at inlet-velocity-based Reynolds numbers of 4800, 9300 and 14,400. Quantities reported include mean velocities, turbulence intensities, Reynolds stresses, and various terms in the Reynolds-Averaged Navier–Stokes (RANS) equations. The results reveal higher shear rates in the wake regions. The streamwise and transverse turbulence fluctuations attained peak value of 85% and 105%, respectively, of the approach mean velocity in the wake regions. The flow evolves fairly rapidly and becomes spatially periodic in the streamwise direction after a relatively short distance. The flow exhibits strong Reynolds number dependence in the developing region but no significant Reynolds number effects are observed in the spatially periodic region. The pressure gradient terms in the streamwise and transverse RANS equations are nearly balanced by the Reynolds stress terms in the recirculation zones, and by the convective terms outside the recirculation region.