Downwash Flow for Neutrally Buoyant Jet in Crossflow

The study reports an experimental investigation of the near wake of a finite-length square stack, with one end mounted on a flat plate and the jet, is emerging from the other free end. Measurements are carried out in a closed-loop low-speed water tunnel at a Reynolds number Re, based on hydraulic diameter (D) and the free-stream velocity (U∞) of 1600 using laser Doppler velocimetry and flow visualization technique. The stack has an aspect ratio (AR) or height-to-diameter ratio H/D of 9.0. The findings of flow visualization experiments have been presented to detect the shedding of coherent vortex structures from the square stack and the downwash of the jet fluid into stack-wake. By observing the streak images of dye visualization, different shear layer structures are identified depending on the velocity ratio (R) ranging from 0.13 to 1.0 that corresponds to the jet Reynolds number (Rej) to vary from 200 to 1700. The detailed flow features are presented and discussed in the near field to understand the flow characteristics.