Experimental Models of Cloud Downbursts in a Crossflow

Abstract:

The behavior of downbursts and their interaction with the ground and structures is investigated through a scaled experimental model.This research investigates the natural weather phenomena known as a downburst utilizing particle image velocimetry (PIV). Downbursts are a relatively under-examined weather phenomena capable of causing up to F3 level damage to structures and ground. The source of much of the structural damage is from the outburst of air on when reaching Earth’s surface causing horizontal shear and vortices. The development of downburst scaling laws have been previously studied, but requires a more robust dataset. Current work has focused on the velocity and vorticity of the downburst region as it reaches the ground. Additionally, downbursts are often accompanied by additional crosswinds. To adequately simulate and study the effects of surface level winds, tests are performed in a water tunnel. Fluid is dropped from cylinders of two different diameters into a water tunnel that is seeded with tracer particles. Utilizing PIV, the vortices of the downburst near the ground are analyzed to develop a better understanding of the scaling involved.