Numerical experiments of axisymmetric flow in a nonuniform gravitational field

Michele G. Macaraeg

doi:10.2514/3.9469

A Triggering Mechanism for Rapid Intensification of Tropical Cyclones

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-14-0193.1 ◽

2015 ◽

Vol 72 (7) ◽

pp. 2666-2681 ◽

Cited By ~ 28

Author(s):

Yoshiaki Miyamoto ◽

Tetsuya Takemi

Keyword(s):

Boundary Layer ◽

Numerical Experiments ◽

Axisymmetric Flow ◽

Three Dimensional ◽

Tangential Velocity ◽

Convective Cell ◽

Rapid Intensification ◽

Rotating Fluid ◽

Coriolis Parameter ◽

Maximum Tangential Velocity

Triggering processes for the rapidly intensifying phase of a tropical cyclone (TC) were investigated on the basis of numerical experiments using a three-dimensional nonhydrostatic model. The results revealed that the rapid intensification of the simulated TC commenced following the formation of a circular cloud, which occurred about 12 h after the TC became essentially axisymmetric. The circular cloud (eyewall) evolved from a cloudy convective cell that was originally generated near the radius of maximum wind speed (RMW). The development of the convective cell in the eyewall was closely related to the radial location of the strong boundary layer convergence of axisymmetric flow. The radius of maximum convergence (RMC) was small relative to the RMW when the TC vortex was weak, which is consistent with the boundary layer theory for a rotating fluid system on a frictional surface. As the TC intensified, the RMC approached the RMW. An eyewall was very likely to form in the simulated TC when the RMC approached the RMW. Because the RMC is theoretically determined by a Rossby number defined by the maximum tangential velocity, RMW, and Coriolis parameter, a series of numerical experiments was conducted by changing the three parameters. The results were consistent with the hypothesis that intensification occurs earlier for larger Rossby numbers. This finding indicates that initial TC vortices with larger Rossby numbers are more likely to experience rapid intensification and, hence, to evolve into strong hurricanes.

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Numerical experiments on the statistics of the gravitational field

Proceedings of the Conference on the Numerical Solution of Ordinary Differential Equations - Lecture Notes in Mathematics ◽

10.1007/bfb0066600 ◽

1974 ◽

pp. 337-359 ◽

Cited By ~ 1

Author(s):

Leon Cohen ◽

Afaq Ahmad

Keyword(s):

Gravitational Field ◽

Numerical Experiments

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A one-dimensional self-gravitating stellar gas

Symposium - International Astronomical Union ◽

10.1017/s0074180900105261 ◽

1966 ◽

Vol 25 ◽

pp. 46-48 ◽

Cited By ~ 2

Author(s):

M. Lecar

Keyword(s):

Gravitational Field ◽

Phase Space ◽

Motion Picture ◽

Space Distribution ◽

Two Dimensional ◽

One Dimensional ◽

Phase Space Distribution ◽

Dimensional Phase Space ◽

The Mean

“Dynamical mixing”, i.e. relaxation of a stellar phase space distribution through interaction with the mean gravitational field, is numerically investigated for a one-dimensional self-gravitating stellar gas. Qualitative results are presented in the form of a motion picture of the flow of phase points (representing homogeneous slabs of stars) in two-dimensional phase space.

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