On vortex intensification due to stretching out of weak satellites

2019 ◽  
Vol 31 (7) ◽  
pp. 075103 ◽  
Author(s):  
G. G. Sutyrin
Keyword(s):  
Vortex Intensification

Experimental study on vortex intensification of gravitational water vortex turbine with novel conical basin

2019 ◽  
Author(s):  
P. S. V. V. Srihari ◽  
P. S. V. V. S. Narayana ◽  
K. V. V. S. Sanath Kumar ◽  
G. Jaya Raju ◽  
K. Naveen ◽  
...  
Keyword(s):  
Experimental Study ◽  
Vortex Intensification

Prediction Skill of GloSea5 model for Stratospheric Polar Vortex Intensification Events

2018 ◽  
Vol 39 (3) ◽  
pp. 211-227
Author(s):  
Hera Kim ◽  
◽  
Seok-Woo Son ◽  
Kanghyun Song ◽  
Sang-Wook Kim ◽  
...  
Keyword(s):  
Polar Vortex ◽  
Prediction Skill ◽  
Stratospheric Polar Vortex ◽  
Vortex Intensification

scholarly journals Interaction between dynamics and thermodynamics during tropical cyclogenesis

2014 ◽  
Vol 14 (6) ◽  
pp. 3065-3082 ◽  
Author(s):  
S. Gjorgjievska ◽  
D. J. Raymond
Keyword(s):  
Vertical Gradient ◽  
Tropical Storm ◽  
Tropical Cyclogenesis ◽  
Surface Mass ◽  
Low Level ◽  
Shallow Layer ◽  
Flux Profile ◽  
Field Campaigns ◽  
Thermodynamic Variables ◽  
Vortex Intensification

Abstract. Observational data of tropical disturbances are analyzed in order to investigate tropical cyclogenesis. Data from 37 cases observed during three field campaigns are used to investigate possible correlations between various dynamic and thermodynamic variables. The results show that a strong mid-level vortex is necessary to promote spin up of the low-level vortex in a tropical cyclone. This paper presents a theory on the mechanism of this process. The mid-level vortex creates a thermodynamic environment conducive to convection with a more bottom-heavy mass flux profile that exhibits a strong positive vertical gradient in a shallow layer near the surface. Mass continuity then implies that the strongest horizontal mass and vorticity convergence occurs near the surface. This results in low-level vortex intensification. For two of the disturbances that were observed during several consecutive days, evolution of the dynamics and thermodynamics is documented. One of these disturbances, Karl, was observed in the period before it intensified into a tropical storm; the other one, Gaston, was observed after it unexpectedly decayed from a tropical storm to a tropical disturbance. A hypothesis on its decay is presented.

Vortex intensification and collapse of the Lissajous-elliptic ring: single- and multi-filament Biot-Savart simulations and visiometrics

1995 ◽  
Vol 299 ◽  
pp. 289-331 ◽  
Author(s):  
Victor M. Fernandez ◽  
Norman J. Zabusky ◽  
Vladimir M. Gryanik
Keyword(s):  
Strain Rate ◽  
Critical Parameters ◽  
Single Filament ◽  
Vortex Reconnection ◽  
Parametric Studies ◽  
Self Similar ◽  
Approach Zero ◽  
Collapse Region ◽  
Dipolar Structure ◽  
Vortex Intensification

The collapsing ‘Lissajous-elliptic’ (LE) vortex ring is examined via quantifications of Single- and multi-filament Biot-Savart numerical simulations. In the single-filament simulations, parametric studies show simple relationships between the collapse boundary and the impulse and energy invariants. Collapse becomes non-monotonic in time, for a sufficiently small initial core ‘radius’. Self-similar, singular-like behaviour of the off-filament strain-rate growth has been observed in a small interval, just prior to core overlapping. The computation of the strain-rate eigenvalues and vortex stretching in a diagnostics box surrounding the collapse region yields patterns observed previously in continuum simulations. New diagnostics are presented, including line densities of the energy and the linear and angular momentum, all of which approach zero in the collapse region of the ring. These diagnostics may provide critical parameters for initiating surgery in a topology-changing algorithm. Our multi-filament simulations exhibit layer-like vortex regions and a ‘torus’-shaped vortex stretching pattern observed previously in continuum periodic-domain simulations of vortex reconnection. Quantifications in a cross-section of the collapse region indicate that the circulation tends to concentrate in the head or frontside of the convecting dipolar structure. This is also the location of the incipient ‘bridge’ which is evolving from the weak filaments that have been convected from the initially outer-vortex regions. The formation of this smaller scale vortex structure exhibits the largest vorticity amplification in the variable-core model simulations.

scholarly journals A semi-empirical model for streamwise vortex intensification

2019 ◽  
Vol 233 (12) ◽  
pp. 4396-4409
Author(s):  
Grant McLelland ◽  
David MacManus ◽  
Chris Sheaf
Keyword(s):  
Empirical Model ◽  
Vortex Core ◽  
Axial Strain ◽  
Empirical Relationship ◽  
Tangential Velocity ◽  
Streamwise Vortex ◽  
Stereoscopic Particle Image Velocimetry ◽  
Wide Range ◽  
Semi Empirical ◽  
Vortex Intensification

Vortex intensification plays an important role in a wide range of flows of engineering interest. One scenario of interest is when a streamwise vortex passes through the contracting streamtube of an aircraft intake. There is, however, limited experimental data of flows of this type to reveal the dominant flow physics and to guide the development of vortex models. To this end, the evolution of wing-tip vortices inside a range of streamtube contractions has been measured using stereoscopic particle image velocimetry. A semi-empirical model has been applied to provide new insight on the role of vorticity diffusion during the intensification process. The analysis demonstrates that for mild flow contractions, vorticity diffusion has a negligible influence due to the low rates of diffusion in the vortex flow prior to intensification and the short convective times associated with the streamtube contraction. As the contraction levels increase, there is a substantial increase in the rates of diffusion which is driven by the greater levels of vorticity in the vortex core. A new semi-empirical relationship, as a function of the local streamtube contraction levels and vortex Reynolds number, has been developed. The model comprises a simple correction to vortex filament theory and provides a significant improvement in the estimation of vortex characteristics in contracting flows. For the range of contractions investigated, errors in the estimation of vortex core radius, peak tangential velocity and vorticity are reduced by an order of magnitude. The model can be applied to estimate the change in vortex characteristics for a range of flows with intense axial strain, such as contracting intake streamtubes and swirling flows in turbomachinery.

Numerical analysis of the vortex intensification of heat transfer in a channel with a set of deep spherical dimples on one of the walls

2002 ◽  
Vol 47 (10) ◽  
pp. 755-757 ◽  
Author(s):  
S. A. Isaev ◽  
A. I. Leontiev ◽  
P. A. Baranov ◽  
I. A. Pyshnyi ◽  
A. E. Usachov
Keyword(s):  
Heat Transfer ◽  
Numerical Analysis ◽  
Vortex Intensification

Vortex Intensification of Heat Transfer in Channels and Pipes with Periodic Elements of Discrete Roughness

2019 ◽  
Vol 92 (6) ◽  
pp. 1509-1516
Author(s):  
S. A. Isaev ◽  
A. D. Chornyi ◽  
Yu. V. Zhukova ◽  
A. A. Vysotskaya ◽  
V. B. Kharchenko
Keyword(s):  
Heat Transfer ◽  
Vortex Intensification

scholarly journals On the Dynamics of Two-Dimensional Hurricane-Like Vortex Symmetrization

2010 ◽  
Vol 67 (11) ◽  
pp. 3559-3580 ◽  
Author(s):  
Y. Martinez ◽  
G. Brunet ◽  
M. K. Yau
Keyword(s):  
Inner Core ◽  
Space Time ◽  
Time Structure ◽  
Small Perturbations ◽  
Eigenmode Analysis ◽  
Space Time Structure ◽  
Core Dynamics ◽  
Spiral Rainbands ◽  
The Impact ◽  
Vortex Intensification

Abstract Despite the fact that asymmetries in hurricanes, such as spiral rainbands, polygonal eyewalls, and mesovortices, have long been observed in radar and satellite imagery, many aspects of their origin, space–time structure, and dynamics still remain unsolved, particularly their role on the vortex intensification. The underlying inner-core dynamics need to be better understood to improve the science of hurricane intensity forecasting. To fill this gap, a simple 2D barotropic “dry” model is used to perform two experiments starting respectively with a monopole and a ring of enhanced vorticity to mimic hurricane-like vortices during incipient and mature stages of development. The empirical normal mode (ENM) technique, together with the Eliassen–Palm (EP) flux calculations, are used to isolate wave modes from the model datasets to investigate their space–time structure, kinematics, and the impact on the changes in the structure and intensity of the simulated hurricane-like vortices. From the ENM diagnostics, it is shown in the first experiment how an incipient storm described by a vortex monopole intensifies by “inviscid damping” of a “discrete-like” vortex Rossby wave (VRW) or quasi mode. The critical radius, the structure, and the propagating properties of the quasi mode are found to be consistent with predictions of the linear eigenmode analysis of small perturbations. In the second experiment, the fastest growing wavenumber-4 unstable VRW modes of a vortex ring reminiscent of a mature hurricane are extracted, and their relation with the polygonal eyewalls, mesovortices, and the asymmetric eyewall contraction are established in consistency with results previously obtained from other authors.

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