Comparison of the Flow Behaviour Around a Wedge-Shaped Bluff Body With and Without Upwind Liquid Spray

The current work experimentally examines the airflow behaviour around a wedge-shaped bluff body. It focuses on comparisons between the baseline case of the bluff body in an airflow and four cases where a counterflow water spray is added upstream of the bluff body. The cases are distinguished using momentum flux ratios of 0 (no spray), 13, 26, 51, and 98 by varying the water velocity and maintaining the airflow constant. The experiments are performed in a low disturbance wind tunnel with a spray bar 22.3 cm upstream of the bluff body. The bluff body has a height of 5.5 cm, thus creating a blockage ratio of approximately 20%. Data is acquired using a Particle Image Velocimetry (PIV) system. Image pairs are processed to create two-dimensional velocity fields that are further processed to better understand the flow behaviour. Influence of the spray injection on the mean velocity and turbulent kinetic energy (TKE) is investigated. The presence of the spray causes a decrease in the mean velocity around the leading edge, sides of the bluff body, and the expanding wake region as the momentum flux ratio increases. The TKE decreases in the wake region and creates an asymmetric field with the main recirculation zone of the highest TKE moving higher from the centerline of the bluff body as the momentum flux ratio increases. Velocity and TKE vertical profiles taken at the same locations show the main variations in their fields along the bluff body upper edge and in the wake region. The water droplets have a significant impact towards causing dampening of the mean velocity and the TKE magnitudes throughout the regions near the bluff body and in the wake.