Compressibility and windspeed limits in tornadoes

Fiedler, Brian H.

doi:10.1080/07055900.1997.9649586

Cited by 7 publications

(2 citation statements)

References 8 publications

(16 reference statements)

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“…There is also a shift toward higher intensity with increased Reynolds number. The reasons are not known with certainty, but Fiedler (1997) cautions about monitoring wind speed maxima. The statistical theory for turbulence—even in a gentle breeze—allows for rare supersonic events, especially on small space and time scales.…”

Section: Discussionmentioning

confidence: 99%

Suction vortices and spiral breakdown in numerical simulations of tornado‐like vortices

Fiedler

2009

Atmospheric Science Letters

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Three-dimensional simulations of tornado-like vortices are presented. The simulations are from a numerical model of the incompressible Navier-Stokes equations, with a Reynolds number, based on scales of the entire recirculating updraft, of up to 4.0 × 10 4 . In a companion axisymmetric model, the theory for the corner flow swirl ratio provides an excellent prediction of the results. For the three-dimensional nonaxisymmetric model, the corner flow swirl ratio is not easily applied a priori, but nonetheless provides a framework for identifying a consistent departure of the three-dimensional simulations from the axisymmetric simulations.

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Section: Discussionmentioning

confidence: 99%

Suction vortices and spiral breakdown in numerical simulations of tornado‐like vortices

Fiedler

2009

Atmospheric Science Letters

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“…This phenomenon can be observed in videos of intense tornadoes. The existence of such vortices and their behavior may be related to the vortices studied in papers by Fiedler (1994); Fiedler and Rotunno (1986); Fiedler (1997); Xia et al (2003); Lewellen and Lewellen (2007a). Fiedler and Rotunno (1986) show that vortices in contact with ground that undergo stretching and an appropriate addition of swirl at the surface can become supercritical.…”

Section: A the Two-dimensional Vortex Gas Theorymentioning

confidence: 87%

Possible Implications of a Vortex Gas Model and Self-Similarity for Tornadogenesis and Maintenance

Dokken¹,

Scholz²,

Shvartsman³

et al. 2014

Preprint

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We describe tornadogenesis and maintenance using the 3-dimensional vortex gas model presented in Chorin (1994) and developed further in Flandoli and Gubinelli (2002). We suggest that high-energy, super-critical vortices in the sense of Benjamin (1962), that have been studied by Fiedler and Rotunno (1986), have negative temperature in the sense of Onsager (1949) play an important role in the model. We speculate that the formation of high-temperature vortices is related to the helicity inherited as they form or tilt into the vertical and their interaction with the surface and boundary layer. We also exploit the notion of self-similarity to justify power laws derived from observations of weak and strong tornadoes presented in Cai (2005); Wurman and Gill (2000); Wurman and Alexander (2005). Analysis of a Bryan Cloud Model (CM1) simulation of a tornadic supercell reveals scaling consistent with the observational studies.

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Wind‐speed limits in numerically simulated tornadoes with suction vortices

Fiedler

1998

Quart J Royal Meteoro Soc

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Three-dimensional numerical simulations of tornado-like vortices are presented. Of particular interest is a regime with multiple suction vortices withn a larger cyclone. The simulations are designed to assess the magnitude and mechanism by which low pressure is sustained in a suction vortex. The pressure in the transient suction vortices can be nine times that supported by the buoyancy of the 'storm'. The low pressure is sustained by transient axial flow; the pressure-gradient force along the axis is balanced by the inertia of the axial flow, rather than by buoyancy.

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Compressibility and windspeed limits in tornadoes

Cited by 7 publications

References 8 publications

Suction vortices and spiral breakdown in numerical simulations of tornado‐like vortices

Suction vortices and spiral breakdown in numerical simulations of tornado‐like vortices

Possible Implications of a Vortex Gas Model and Self-Similarity for Tornadogenesis and Maintenance

Wind‐speed limits in numerically simulated tornadoes with suction vortices

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