Axisymmetric Tornado Simulations with a Semi-Slip Boundary

Fiedler, Brian H.

doi:10.3390/fluids2040068

Cited by 5 publications

(1 citation statement)

References 14 publications

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“…Some studies have also noted that tornado development in supercells may be impacted by elevation changes [18][19][20][21][22] while others have explored the link between tornado formation and variations in surface roughness [22][23][24]. Numerical simulations have also shown that the development of near-ground rotation is sensitive to surface friction magnitude [25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Idealized Simulations of a Supercell Interacting with an Urban Area

Naylor,

Berry,

Gosney

2024

Meteorology

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Idealized simulations with a cloud-resolving model are conducted to examine the impact of a simplified city on the structure of a supercell thunderstorm. The simplified city is created by enhancing the surface roughness length and/or surface temperature relative to the surroundings. When the simplified city is both warmer and has larger surface roughness relative to its surroundings, the supercell that passes over it has a larger updraft helicity (at both midlevels and the surface) and enhanced precipitation and hail downwind of the city, all relative to the control simulation. The storm environment within the city has larger convective available potential energy which helps stimulate stronger low-level updrafts. Storm relative helicity (SRH) is actually reduced over the city, but enhanced in a narrow band on the northern edge of the city. This band of larger SRH is ingested by the primary updraft just prior to passing over the city, corresponding with enhancement to the near-surface mesocyclone. Additional simulations in which the simplified city is altered by removing either the heat island or surface roughness length gradient reveal that the presence of a heat island is most closely associated with enhancements in updraft helicity and low-level updrafts relative to the control simulation.

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Section: Introductionmentioning

confidence: 99%

Idealized Simulations of a Supercell Interacting with an Urban Area

Naylor,

Berry,

Gosney

2024

Meteorology

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Modeling the effects of slip on dipole–wall collision problems using a lattice Boltzmann equation method

2020

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We study the physics of flow due to the interaction between a viscous dipole and boundaries that permit slip. This includes partial and free slip, and interactions near corners. The problem is investigated by using a two relaxation time lattice Boltzmann equation with moment-based boundary conditions. Navier-slip conditions, which involve gradients of the velocity, are formulated and applied locally. The implementation of free-slip conditions with the moment-based approach is discussed. Collision angles of 0°, 30°, and 45° are investigated. Stable simulations are shown for Reynolds numbers between 625 and 10 000 and various slip lengths. Vorticity generation on the wall is shown to be affected by slip length, angle of incidence, and Reynolds number. An increase in wall slippage causes a reduction in the number of higher-order dipoles created. This leads to a decrease in the magnitude of the enstrophy peaks and reduces the dissipation of energy. The dissipation of the energy and its relation to the enstrophy are also investigated theoretically, confirming quantitatively how the presence of slip modifies this relation.

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Recent developments in tornado theory and observations

Rotunno,

Bluestein

2024

Rep. Prog. Phys.

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This article critically reviews research on tornado theory and observations over the last decade. From the theoretical standpoint, the major advances have come through improved numerical-simulation models of supercell convective storms, the tornado’s parent circulation. These simulations are carried out on a large domain (to capture the supercell's circulation system), but with high grid resolution and improved representations of sub-grid physics (to capture the tornado). These simulations offer new insights into how and why tornadoes form in some supercells, but not others. Observational advances have come through technological improvements of mobile Doppler radars capable of rapid scanning and dual-polarization measurements, which offer a much more accurate view of tornado formation, tornado structure, and the tornado's place within its parent supercell.

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Axisymmetric Tornado Simulations with a Semi-Slip Boundary

Cited by 5 publications

References 14 publications

Idealized Simulations of a Supercell Interacting with an Urban Area

Idealized Simulations of a Supercell Interacting with an Urban Area

Modeling the effects of slip on dipole–wall collision problems using a lattice Boltzmann equation method

Recent developments in tornado theory and observations

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