Estimation of Maximum Wind Speeds in Tornadoes

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Dergarabedian, Paul ; Fendell, Francis (2011)

A method is proposed for rapidly estimating the maximum value of the azimuthal velocity component (maximum swirling speed) in tornadoes and waterspouts. The method requires knowledge of the cloud-deck height and a photograph of the funnel cloud—data usually available. Calculations based on this data confirm that the lower maximum wind speeds suggested by recent workers (roughly one-quarter of the sonic speed for sea-level air) are more plausible for tornadoes than the sonic speed sometimes cited a decade ago. Comparison in a few cases with maximum wind speeds determined either by spray-tracking on motion pictures of a waterspout or by another method reported by the authors elsewhere (using the tephigram for air at the outer edge of the whirl) yields compatible results.DOI: 10.1111/j.2153-3490.1970.tb00517.x
  • References (11)
    11 references, page 1 of 2

    Bretherton, F. P. 1967. The time-dependent motion due to a cylinder moving in an unboundedrotating or stratified fluid. J. Fluid Mech. 28, 545.

    Janowitz, G. S. 1968. On wakes in stratified fluids. J. Fluid Mech 33, 417.

    Long, R . R . 1954. Some aspects of the flow of stratified fluids. 11. Experiments with a two-fluid system. Tellus 6, 97.

    Long, R . R. 1955. Some aspects of the flow of stratified fluids. 111. Continuous density gradients. Tellus 7, 341.

    Long, R. R. 1959. The motion of fluids with density stratification. J. Beophys. Res. 64, 2151.

    Martin, S. & Long, R . R. 1968. The slow motion of a flat plate in a viscous, stratified fluid. J. Fluid Mech. 31, 669.

    Miles, J. W. 1969. A slender body in a rotating flow. J. Fluid Mech. 36, 265.

    Taylor, G. I. 1922. The motion of asphereinarotating liquid. Proc. Roy. Soc. ( A )102, 180.

    Trustrum, K. 1964. Rotating and stratified fluid flow. J. Fluid Mech. 19, 415.

    Yih, C. S. & Guha, C. R. 1955. Hydraulic jump in a fluid system of two layers. Tellus 8, 358.

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