Experimental investigation of the near-surface flow dynamics in downburst-like impinging jets.
Saved in:
| Title: | Experimental investigation of the near-surface flow dynamics in downburst-like impinging jets. |
|---|---|
| Authors: | Canepa, Federico1,2 (AUTHOR) federico.canepa@edu.unige.it, Burlando, Massimiliano1 (AUTHOR), Romanic, Djordje1,2,3 (AUTHOR), Solari, Giovanni1 (AUTHOR), Hangan, Horia2,4 (AUTHOR) |
| Source: | Environmental Fluid Mechanics. Aug2022, Vol. 22 Issue 4, p921-954. 34p. |
| Subjects: | University of Western Ontario, Microbursts, Transients (Dynamics), Wind measurement, Vertical drafts (Meteorology), Time series analysis, Turbulence, Advection-diffusion equations, Wind speed |
| Geographic Terms: | Canada |
| Abstract: | Downbursts are strong downdrafts that originate from thunderstorm clouds and create vigorous radial outflows upon hitting the ground. This study is part of the comprehensive experimental research on downburst outflows produced as large-scale impinging jets in the WindEEE Dome simulator at Western University, Canada. The 2800 tests carried out form the largest database of experimental measurements on downburst winds developed thus far, which is made available to the public in its whole and described in detail in a complementary study. Therefore, the current manuscript merely focuses on the data post-processing outcomes and interpretation of results from a selected subset of measurements. Impinging jets are here simulated as transient phenomena in which velocity time series are characterized by a sudden ramp-up of velocity, followed by the velocity peak, a short statistically stationary region, and the final velocity slowdown, as it is expected to occur in the actual downbursts. A dominant velocity peak that was systematically observed in all velocity records is associated with the radial advection of the primary vortex in the outflow. Depending on the radial distance from the downdraft, the primary vortex was sometimes preceded by a secondary, much smaller, vortex close to the surface. Vertical profiles of mean velocity and turbulence intensity are for the first time characterized through the extent of a downburst-like event in the spatiotemporal domain. Particularly, these profiles rapidly change in relation to the passage of the primary vortex and consequent variation of the surface layer thickness. This study lays out a foundation for an experimental model of non-stationary downburst outflows to come. Article highlights: Large experimental campaign and public database of measurements on transient downburst-like impinging jets. Characterization of the spatiotemporal evolution of wind speed and turbulence profiles. Measuring the effects of the primary and secondary vortices in the outflow on velocity and turbulence profiles. [ABSTRACT FROM AUTHOR] |
| Copyright of Environmental Fluid Mechanics is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
|
Full text is not displayed to guests.
Login for full access.
|
|
| Abstract: | Downbursts are strong downdrafts that originate from thunderstorm clouds and create vigorous radial outflows upon hitting the ground. This study is part of the comprehensive experimental research on downburst outflows produced as large-scale impinging jets in the WindEEE Dome simulator at Western University, Canada. The 2800 tests carried out form the largest database of experimental measurements on downburst winds developed thus far, which is made available to the public in its whole and described in detail in a complementary study. Therefore, the current manuscript merely focuses on the data post-processing outcomes and interpretation of results from a selected subset of measurements. Impinging jets are here simulated as transient phenomena in which velocity time series are characterized by a sudden ramp-up of velocity, followed by the velocity peak, a short statistically stationary region, and the final velocity slowdown, as it is expected to occur in the actual downbursts. A dominant velocity peak that was systematically observed in all velocity records is associated with the radial advection of the primary vortex in the outflow. Depending on the radial distance from the downdraft, the primary vortex was sometimes preceded by a secondary, much smaller, vortex close to the surface. Vertical profiles of mean velocity and turbulence intensity are for the first time characterized through the extent of a downburst-like event in the spatiotemporal domain. Particularly, these profiles rapidly change in relation to the passage of the primary vortex and consequent variation of the surface layer thickness. This study lays out a foundation for an experimental model of non-stationary downburst outflows to come. Article highlights: Large experimental campaign and public database of measurements on transient downburst-like impinging jets. Characterization of the spatiotemporal evolution of wind speed and turbulence profiles. Measuring the effects of the primary and secondary vortices in the outflow on velocity and turbulence profiles. [ABSTRACT FROM AUTHOR] |
|---|---|
| ISSN: | 15677419 |
| DOI: | 10.1007/s10652-022-09870-5 |
