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Western University

Downburst

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Full-Text Articles in Engineering

Numerical Simulation And Scaling Of Thunderstorm Downburst Outflows, Cristiano Andre Rodrigues Kondo Sep 2021

Numerical Simulation And Scaling Of Thunderstorm Downburst Outflows, Cristiano Andre Rodrigues Kondo

Electronic Thesis and Dissertation Repository

A downburst is a natural phenomenon that occurs during thunderstorms, creating hazards and damage to infrastructure due to the strong winds produced. This research contributes to the current literature by applying the Lundgren et al. scaling parameters (R0, T0, V0) to scale cooling source (CS) downburst simulations. The research also investigates the effects of the environmental lapse rate (ELR) on full-scale downburst outflows and compares the full-cloud model with the subcloud model simulations. The results showed that the scaling parameters preserve the temporal and vertical radial wind speed profile shape, as well as the …


Experimental Modelling Of Downburst And Downburst Line Outflows, Kyle Graat Oct 2020

Experimental Modelling Of Downburst And Downburst Line Outflows, Kyle Graat

Electronic Thesis and Dissertation Repository

The outflow velocity vector fields of simulated stationary thunderstorm downbursts and downburst lines were resolved in two plane orientations, vertical and horizontal, using a dense fluid release system and Particle Image Velocimetry. Single event releases were scaled to show agreement with past studies based on radial velocity magnitude and location and radial and vertical front propagation. The vortex trajectory of a single event using the vortex aspect ratio supported density's role in the outflow after the time and location of the maximum radial velocity. The interaction between two release events varied temporally and spatially and showed that the interaction region's …


Transient Analysis Of Full Scale And Experimental Downburst Flows, Junayed Chowdhury Nov 2018

Transient Analysis Of Full Scale And Experimental Downburst Flows, Junayed Chowdhury

Electronic Thesis and Dissertation Repository

Downbursts are highly transient natural phenomena which produce strong downdrafts evolving from a cumulonimbus cloud They induce an outburst of damaging winds on or near to the ground causing an immense damage to the ground mounted structures and aircrafts. This study investigates the transient nature of downbursts using wind speed records from full scale downburst events employing an objective methodology. This method can detect the abrupt change points in a downburst time series based on statistical parameters such as mean, standard deviation and linear trend. In addition to the analysis of the full scale downburst events, several large scale experimental …


Numerical Investigation Of Full Scale Thunderstorm Downbursts: A Parametric Study And Comparison To Meteorological Model, Christopher Oreskovic Apr 2016

Numerical Investigation Of Full Scale Thunderstorm Downbursts: A Parametric Study And Comparison To Meteorological Model, Christopher Oreskovic

Electronic Thesis and Dissertation Repository

A series of Large Eddy Simulations using an atmospheric meteorological cloud model have been used to investigate the important geometric and thermal parameters that influence a thunderstorm downburst outflow, as it pertains specifically to the idealized cooling source model. A separate set of Large Eddy Simulations make use of the same idealized cooling source model, in a realistic atmospheric base state using real field sounding data, in an attempt to make a quantifiable comparison to a downburst from a full cloud simulation. Randomness has been added to the cooling source forcing function to mimic the thermal variation in a real …