Downburst-like experimental measurements of two vertical-axis impinging jets at the WindEEE Dome

This dataset presents the comprehensive experimental campaign of measurements on downburst-like outflows produced by large-scale impinging jets in the WindEEE Dome simulator at Western University, Canada. Downbursts are strong downdrafts that originate from thunderstorm clouds and create vigorous radial outflows upon hitting the ground. The near-surface winds in downburst outflows can reach the velocity of a strong tornado. The dataset of measurements is presented in two parts related to the two jet velocities adopted in the experiments, respectively Vjet = 8.9 m/s and Vjet = 16.4 m/s. The three-component velocity measurements were recorded by means of 7 Cobra probes (sampling frequency 2500 Hz) mounted on a stiff mast. The mast was subsequently positioned at ten radial r/D distances (D is the jet diameter) in respect to the jet touchdown position (r/D = 0), in the range 0.2-2.0 with an increment of 0.2. The heights (z) of the probes on the mast were 0.04, 0.10, 0.15, 0.20, 0.27, 0.42 and 0.50 m. Impinging jets are simulated as transient phenomena through the opening and closing of the nozzle that connects the test chamber and the upper chamber of the dome, which is pressurized to produce the vertical jet after nozzle opening. Therefore, the velocity records are characterized by a sudden ramp-up of velocity, followed by a velocity peak, a statistically-stationary region, and the final velocity slowdown, as it is expected to occur in the real case. The diameter of the nozzle was D = 3.2 m, while the ceiling height of the testing chamber is H = 3.75 m. For every r/D position, each experiment with the same initial condition (i.e. Vjet) was repeated 20 times to inspect the repeatability of the tests and to build more statistical significance of the results. Each velocity record lasted 10 s and the duration of the downburst-like part of the record varied between 3-5 s. The 2800 total time series (2 Vjet x 20 repetitions x 10 r/D positions x 7 heights) of downburst-like outflows carried out inside the WindEEE Dome simulator represent the largest experimental campaign on downburst winds performed thus far