Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Computer modelling of close-to-ground tornado wind-fields for different tornado widths
https://orcid.org/0000-0003-4944-2718
Abstract Tangential velocity (Vt) of tornadoes is the major parameter that causes building damage. In-field tornado measurements are less reliable at less than 20 m above ground level (AGL). Laboratory tornado simulators suggest that swirl ratio (S) and radius (ro) are the major tornado parameters that influence the Vt. However, due to scaling problems, the laboratory simulators also report the Vt at greater than 20 m AGL. Well-refined computational fluid dynamics (CFD) models can evaluate the Vt at less than 10 m AGL. However, the CFD models are limited to ro = 1.0 km, and the effect of ro on Vt is not investigated. The aim of this study is to investigate the maximum Vt for different ro close to ground. Simulation results show that increasing ro decreases the maximum Vt with respect to Vro. Moreover, by increasing ro, the corresponding elevation of occurrence of maximum Vt (zmax) will increase. However, for all tornado radii, the zmax is between 20 m and 64 m AGL. In addition, results show that for all ro, the radial Vt profile has two peaks at z < 10 m AGL due to strong shear force close to the ground and at higher elevation the profile transits to Rankine Combined Vortex Model (RCVM).
Highlights When the tornado or tornado chamber radius (ro) increases the touchdown swirl ratio increases. The increase in radius (r) reduces the ratio of the maximum tangential velocity to radial velocity. Close to the ground, the radial profile of the tangential velocity has two peaks. Close to the ground the radial velocity profile is not same as the Rankine Combined Vortex Model.
Computer modelling of close-to-ground tornado wind-fields for different tornado widths
https://orcid.org/0000-0003-4944-2718
Abstract Tangential velocity (Vt) of tornadoes is the major parameter that causes building damage. In-field tornado measurements are less reliable at less than 20 m above ground level (AGL). Laboratory tornado simulators suggest that swirl ratio (S) and radius (ro) are the major tornado parameters that influence the Vt. However, due to scaling problems, the laboratory simulators also report the Vt at greater than 20 m AGL. Well-refined computational fluid dynamics (CFD) models can evaluate the Vt at less than 10 m AGL. However, the CFD models are limited to ro = 1.0 km, and the effect of ro on Vt is not investigated. The aim of this study is to investigate the maximum Vt for different ro close to ground. Simulation results show that increasing ro decreases the maximum Vt with respect to Vro. Moreover, by increasing ro, the corresponding elevation of occurrence of maximum Vt (zmax) will increase. However, for all tornado radii, the zmax is between 20 m and 64 m AGL. In addition, results show that for all ro, the radial Vt profile has two peaks at z < 10 m AGL due to strong shear force close to the ground and at higher elevation the profile transits to Rankine Combined Vortex Model (RCVM).
Highlights When the tornado or tornado chamber radius (ro) increases the touchdown swirl ratio increases. The increase in radius (r) reduces the ratio of the maximum tangential velocity to radial velocity. Close to the ground, the radial profile of the tangential velocity has two peaks. Close to the ground the radial velocity profile is not same as the Rankine Combined Vortex Model.
Computer modelling of close-to-ground tornado wind-fields for different tornado widths
https://orcid.org/0000-0003-4944-2718
Abstract Tangential velocity (Vt) of tornadoes is the major parameter that causes building damage. In-field tornado measurements are less reliable at less than 20 m above ground level (AGL). Laboratory tornado simulators suggest that swirl ratio (S) and radius (ro) are the major tornado parameters that influence the Vt. However, due to scaling problems, the laboratory simulators also report the Vt at greater than 20 m AGL. Well-refined computational fluid dynamics (CFD) models can evaluate the Vt at less than 10 m AGL. However, the CFD models are limited to ro = 1.0 km, and the effect of ro on Vt is not investigated. The aim of this study is to investigate the maximum Vt for different ro close to ground. Simulation results show that increasing ro decreases the maximum Vt with respect to Vro. Moreover, by increasing ro, the corresponding elevation of occurrence of maximum Vt (zmax) will increase. However, for all tornado radii, the zmax is between 20 m and 64 m AGL. In addition, results show that for all ro, the radial Vt profile has two peaks at z < 10 m AGL due to strong shear force close to the ground and at higher elevation the profile transits to Rankine Combined Vortex Model (RCVM).
Highlights When the tornado or tornado chamber radius (ro) increases the touchdown swirl ratio increases. The increase in radius (r) reduces the ratio of the maximum tangential velocity to radial velocity. Close to the ground, the radial profile of the tangential velocity has two peaks. Close to the ground the radial velocity profile is not same as the Rankine Combined Vortex Model.
Computer modelling of close-to-ground tornado wind-fields for different tornado widths
Kashefizadeh, M. Hossein (Autor:in) / Verma, Sumit (Autor:in) / Selvam, R. Panneer (Autor:in)
Journal of Wind Engineering and Industrial Aerodynamics ; 191 ; 32-40
13.05.2019
9 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch