Journal articles: 'Vorticity'

1

Zabusky, N. J. "Vorticity." Science 261, no. 5129 (September 24, 1993): 1757–58. http://dx.doi.org/10.1126/science.261.5129.1757.

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Miura, Hideaki, and Shigeo Kida. "Vorticity Generation by Shock-Vorticity Interaction." Journal of the Physical Society of Japan 63, no. 11 (November 15, 1994): 4000–4010. http://dx.doi.org/10.1143/jpsj.63.4000.

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Benedetto, Elmo, Gerardo Iovane, and Ettore Laserra. "Vorticity of Matter or Vorticity of Space?" Gravitation and Cosmology 27, no. 1 (January 2021): 85–88. http://dx.doi.org/10.1134/s0202289321010059.

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Rotunno, R., V. Grubišić, and P. K. Smolarkiewicz. "Vorticity and Potential Vorticity in Mountain Wakes." Journal of the Atmospheric Sciences 56, no. 16 (August 1999): 2796–810. http://dx.doi.org/10.1175/1520-0469(1999)056<2796:vapvim>2.0.co;2.

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Pérez-Madrid, A., T. Alarcón, and J. M. Rubı́. "Vorticity ratchet." Physica A: Statistical Mechanics and its Applications 325, no. 1-2 (July 2003): 55–61. http://dx.doi.org/10.1016/s0378-4371(03)00183-3.

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Nof, Doron. "Vorticity Control." Journal of Physical Oceanography 17, no. 10 (October 1987): 1758–71. http://dx.doi.org/10.1175/1520-0485(1987)017<1758:vc>2.0.co;2.

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7

Herbert, Fritz. "The physics of potential vorticity." Meteorologische Zeitschrift 16, no. 3 (June 21, 2007): 243–54. http://dx.doi.org/10.1127/0941-2948/2007/0198.

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Névir, Peter. "Ertel's vorticity theorems, the particle relabelling symmetry and the energy-vorticity theory of fluid mechanics." Meteorologische Zeitschrift 13, no. 6 (December 23, 2004): 485–98. http://dx.doi.org/10.1127/0941-2948/2004/0013-0485.

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Kida, Shigeo, and Masanori Takaoka. "Breakdown of Frozen Motion of Vorticity Fieldand Vorticity Reconnection." Journal of the Physical Society of Japan 60, no. 7 (July 15, 1991): 2184–96. http://dx.doi.org/10.1143/jpsj.60.2184.

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10

Xiao-Peng, Cui, Gao Shou-Ting, and Wu Guo-Xiong. "Moist Potential Vorticity and Up-Sliding Slantwise Vorticity Development." Chinese Physics Letters 20, no. 1 (December 9, 2002): 167–69. http://dx.doi.org/10.1088/0256-307x/20/1/350.

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Huachen, Pan, and Zhang Shiying. "Measurement of streamwise vorticity using a vane vorticity meter." International Journal of Heat and Fluid Flow 8, no. 1 (March 1987): 72–75. http://dx.doi.org/10.1016/0142-727x(87)90054-3.

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12

Moreira, R. M., and J. T. A. Chacaltana. "Vorticity effects on nonlinear wave–current interactions in deep water." Journal of Fluid Mechanics 778 (July 31, 2015): 314–34. http://dx.doi.org/10.1017/jfm.2015.385.

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The effects of uniform vorticity on a train of ‘gentle’ and ‘steep’ deep-water waves interacting with underlying flows are investigated through a fully nonlinear boundary integral method. It is shown that wave blocking and breaking can be more prominent depending on the magnitude and direction of the shear flow. Reflection continues to occur when sufficiently strong adverse currents are imposed on ‘gentle’ deep-water waves, though now affected by vorticity. For increasingly positive values of vorticity, the induced shear flow reduces the speed of right-going progressive waves, introducing significant changes to the free-surface profile until waves are completely blocked by the underlying current. A plunging breaker is formed at the blocking point when ‘steep’ deep-water waves interact with strong adverse currents. Conversely negative vorticities augment the speed of right-going progressive waves, with wave breaking being detected for strong opposing currents. The time of breaking is sensitive to the vorticity’s sign and magnitude, with wave breaking occurring later for negative values of vorticity. Stopping velocities according to nonlinear wave theory proved to be sufficient to cause wave blocking and breaking.

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13

Sizykh, G. B. "Vorticity addition method." Fluid Dynamics 51, no. 3 (May 2016): 321–26. http://dx.doi.org/10.1134/s0015462816030030.

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14

Hur, Vera Mikyoung. "Stokeswaves with vorticity." Journal d'Analyse Mathématique 113, no. 1 (January 2011): 331–86. http://dx.doi.org/10.1007/s11854-011-0010-2.

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15

Ellington, C. P., and E. Tytell. "Vorticity in air." Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 126 (July 2000): 45. http://dx.doi.org/10.1016/s1095-6433(00)80088-4.

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16

Shouting, Gao, and Lei Ting. "Streamwise vorticity equation." Advances in Atmospheric Sciences 17, no. 3 (September 2000): 339–47. http://dx.doi.org/10.1007/s00376-000-0027-4.

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17

Lee, Mario, and Chih-Ming Ho. "Lift Force of Delta Wings." Applied Mechanics Reviews 43, no. 9 (September 1, 1990): 209–21. http://dx.doi.org/10.1115/1.3119169.

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On a delta wing, the separation vorticies can be stationary due to the balance of the vorticity surface flux and the axial convection along the swept leading edge. These stationary vortices keep the wing from losing lift. A highly swept delta wing reaches the maximum lift at an angle of attack of about 40°, which is more than twice as high as that of a two-dimensional airfoil. In this paper, the experimental results of lift forces for delta wings are reviewed from the perspective of fundamental vorticity balance. The effects of different operational and geometrical parameters on the performance of delta wings are surveyed.

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18

Millán, Luis F., Gloria L. Manney, and Zachary D. Lawrence. "Reanalysis intercomparison of potential vorticity and potential-vorticity-based diagnostics." Atmospheric Chemistry and Physics 21, no. 7 (April 7, 2021): 5355–76. http://dx.doi.org/10.5194/acp-21-5355-2021.

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Abstract. Global reanalyses from data assimilation systems are among the most widely used datasets in weather and climate studies, and potential vorticity (PV) from reanalyses is invaluable for many studies of dynamical and transport processes. We assess how consistently modern reanalyses represent potential vorticity (PV) among each other, focusing not only on PV but also on process-oriented dynamical diagnostics including equivalent latitude calculated from PV and PV-based tropopause and stratospheric polar vortex characterization. In particular we assess the National Centers for Environmental Prediction Climate Forecast System Reanalysis/Climate Forecast System, version 2 (CFSR/CFSv2) reanalysis, the European Centre for Medium-Range Weather Forecasts Interim (ERA-Interim) reanalysis, the Japanese Meteorological Agency's 55-year (JRA-55) reanalysis, and the NASA Modern-Era Retrospective analysis for Research and Applications, version 2 (MERRA-2). Overall, PV from all reanalyses agrees well with the reanalysis ensemble mean, providing some confidence that all of these recent reanalyses are suitable for most studies using PV-based diagnostics. Specific diagnostics where some larger differences are seen include PV-based tropopause locations in regions that have strong tropopause gradients (such as around the subtropical jets) or are sparse in high-resolution data (such as over Antarctica), and the stratospheric polar vortices during fall vortex formation and (especially) spring vortex breakup; studies of sensitive situations or regions such as these should examine PV from multiple reanalyses.

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19

Ohkitani, Koji. "Kinematics of vorticity: Vorticity-strain conjugation in incompressible fluid flows." Physical Review E 50, no. 6 (December 1, 1994): 5107–10. http://dx.doi.org/10.1103/physreve.50.5107.

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20

Dahl, Johannes M. L. "Tilting of Horizontal Shear Vorticity and the Development of Updraft Rotation in Supercell Thunderstorms." Journal of the Atmospheric Sciences 74, no. 9 (August 30, 2017): 2997–3020. http://dx.doi.org/10.1175/jas-d-17-0091.1.

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Abstract The question of how rotation arises in sheared updrafts is analyzed using the shear and curvature vorticity framework. Local rotation exists where the shear and curvature vorticity have a similar magnitude and the same sign, such that parcels are in near-solid-body rotation. It is shown that the tilting terms of the vertical vorticity equation cannot explain the development of local rotation in the canonical cases where the horizontal vorticity is either purely streamwise or purely crosswise. Rather, vertical shear vorticity develops if crosswise vorticity is tilted, and vertical curvature vorticity develops if streamwise vorticity is tilted. To analyze how local rotation develops, two simulations of updrafts in an environment with crosswise and mostly streamwise vorticity, respectively, are discussed. A trajectory analysis is performed and shear and curvature vorticity budgets are analyzed. It is found that much of the horizontal vorticity near the updraft becomes streamwise, which results from pressure gradient accelerations in the vicinity of the updraft. Consequently, in the analyzed scenarios, the tilting mechanism results primarily in vertical curvature vorticity. Local rotation is achieved via an interchange process that facilitates a partial conversion of vertical curvature vorticity to vertical shear vorticity. Updraft rotation in supercells thus does not result from tilting of horizontal vorticity alone, but partial conversion of curvature to shear vorticity is also required.

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21

Davies-Jones, Robert. "Roles of Streamwise and Transverse Partial-Vorticity Components in Steady Inviscid Isentropic Supercell-Like Flows." Journal of the Atmospheric Sciences 74, no. 9 (August 31, 2017): 3021–41. http://dx.doi.org/10.1175/jas-d-16-0332.1.

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Abstract Investigations of tornadogenesis in supercells attempt to find the origin of the tornado’s large vorticity by determining vorticity generation and amplification along trajectories that enter the tornado from a horizontally uniform unstable environment. Insights into tornadogenesis are provided by finding analytical formulas for vorticity variations along streamlines in idealized, steady, inviscid, isentropic inflows of dry air imported from the environment. The streamlines and vortex lines lie in the stationary isentropic surfaces so the vorticity is 2D. The transverse vorticity component (positive leftward of the streamlines) arises from imported transverse vorticity and from baroclinic vorticity accumulated in streamwise temperature gradients. The streamwise component stems from imported streamwise vorticity, from baroclinic vorticity accrued in transverse temperature gradients, and from positive transverse vorticity that is turned streamwise in cyclonically curved flow by a “river-bend process.” It is amplified in subsiding air as it approaches the ground. Streamwise stretching propagates a parcel’s streamwise vorticity forward in time. In steady flow, vorticity decomposes into baroclinic vorticity and two barotropic parts ωBTIS and ωBTIC arising from imported storm-relative streamwise vorticity (directional shear) and storm-relative crosswise vorticity (speed shear), respectively. The Beltrami vorticity ωBTIS is purely streamwise. It explains why abundant environmental storm-relative streamwise vorticity close to ground favors tornadic supercells. It flows directly into the updraft base unmodified apart from streamwise stretching, establishing mesocyclonic rotation and strong vortex suction at low altitudes. Increase (decrease) in storm-relative environmental wind speed with height near the ground accelerates (delays) tornadogenesis as positive (negative) ωBTIC is turned into streamwise (antistreamwise) vorticity within cyclonically curved flow around the mesocyclone.

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22

Dahl, Johannes M. L., Matthew D. Parker, and Louis J. Wicker. "Imported and Storm-Generated Near-Ground Vertical Vorticity in a Simulated Supercell*." Journal of the Atmospheric Sciences 71, no. 8 (July 23, 2014): 3027–51. http://dx.doi.org/10.1175/jas-d-13-0123.1.

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Abstract The authors use a high-resolution supercell simulation to investigate the source of near-ground vertical vorticity by decomposing the vorticity vector into barotropic and nonbarotropic parts. This way, the roles of ambient and storm-generated vorticity can be isolated. A new Lagrangian technique is employed in which material fluid volume elements are tracked to analyze the rearrangement of ambient vortex-line segments. This contribution is interpreted as barotropic vorticity. The storm-generated vorticity is treated as the residual between the known total vorticity and the barotropic vorticity. In the simulation the development of near-ground vertical vorticity is an outflow phenomenon. There are distinct “rivers” of cyclonic shear vorticity originating from the base of downdrafts that feed into the developing near-ground vortex. The origin of these rivers of vertical vorticity is primarily horizontal baroclinic production, which is maximized in the lowest few hundred meters AGL. Subsequently, this horizontal vorticity is tilted upward while the parcels are still descending. The barotropic vorticity remains mostly streamwise along the analyzed trajectories and does not acquire a large vertical component as the parcels reach the ground. Thus, the ambient vorticity that is imported into the storm contributes only a small fraction of the total near-ground vertical vorticity.

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23

Markowski, Paul, and Christina Hannon. "Multiple-Doppler Radar Observations of the Evolution of Vorticity Extrema in a Convective Boundary Layer." Monthly Weather Review 134, no. 1 (January 1, 2006): 355–74. http://dx.doi.org/10.1175/mwr3060.1.

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Abstract Overdetermined, dual-Doppler wind syntheses are used to document the evolution, structure, and dynamics of vertical vorticity extrema observed in a convective boundary layer during the 12 June 2002 International H2O Project (IHOP) mission. Discrete vertical vorticity extrema having horizontal scales of 1–2 km can be observed continuously for periods exceeding an hour. The evolution of the vorticity field is characterized by complex interactions among vorticity extrema and between the vertical vorticity and vertical velocity fields. The most prominent vorticity maxima have amplitudes of approximately 0.01 s−1 and are associated with retrieved pressure deficits of order 0.1 mb. The vorticity extrema weaken with height and tilt in the presence of vertical wind shear. Advection and propagation both contribute substantially to the motion of the vorticity extrema. Amplifications of vertical vorticity are closely linked to the intensification of updrafts. Both stretching and tilting can contribute significantly to the vorticity budgets of the air parcels comprising the vorticity extrema, and their relative importance varies with elevation, evolutionary stage, and from one vorticity extremum to another. It is therefore difficult to generalize about the dynamics of the vorticity extrema. It also is difficult to generalize about the helicity of the vorticity maxima and suppression of mixing for similar reasons. The weakening of vertical vorticity extrema is closely tied to the weakening of updrafts. In some cases, downward-directed vertical pressure gradient forces due to vertical gradients of rotation bring about updraft weakening and vorticity demise. An improved understanding of the nature of boundary layer vortices could have large relevance to convection initiation owing to feedbacks between vertical velocity and vorticity.

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24

Davies-Jones, Robert. "Integrals of the Vorticity Equation. Part I: General Three- and Two-Dimensional Flows." Journal of the Atmospheric Sciences 63, no. 2 (February 1, 2006): 598–610. http://dx.doi.org/10.1175/jas3646.1.

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Abstract The integral of the vector vorticity equation for the vorticity of a moving parcel in 3D baroclinic flow with friction is cast in a new form. This integral of the vorticity equation applies to synoptic-scale or mesoscale flows and to deep compressible or shallow Boussinesq motions of perfectly clear or universally saturated air. The present integral is equivalent to that of Epifanio and Durran in the Boussinesq limit, but its simpler form reduces easily to Dutton’s integral when the flow is assumed to be isentropic and frictionless. The integral for vorticity has the following physical interpretation. The vorticity of a parcel is composed of barotropic vorticity; baroclinic vorticity, which originates from solenoidal generation; and vorticity stemming from frictional generation. Its barotropic vorticity is the result of freezing into the fluid the w field (specific volume times vorticity) that is present at the initial time. Its baroclinic vorticity is the vector sum of contributions from small subintervals of time that partition the interval between initial and current times. In each subinterval, the baroclinic torque generates a small vector element of vorticity and hence w. The contribution to the current baroclinic vorticity is the result of freezing this element of w into the fluid immediately after its formation. The physical interpretation of vorticity owing to frictional generation is identical except the torque is frictional rather than solenoidal. The baroclinic vorticity is decomposed into a part that would occur if the current entropy of the flow were conserved materially backward in time to the initial time and an adjustment term that accounts for production of entropy gradients in material coordinates during this interval. A method for computing all the vorticity parts in an Eulerian framework within a 3D numerical model is outlined. The usefulness of the 3D vorticity integral is demonstrated further by deriving Eckart’s, Bjerknes’s, and Kelvin’s circulation theorems from it in relatively few steps, and by showing that the associated expression for potental vorticity is an integral of the potential vorticity equation and implies conservation of potential vorticity for isentropic frictionless motion of clear air (Ertel’s theorem). Last, a formula for the helicity density of a parcel is obtained from the vorticity integral and an expression for the parcel’s velocity, and is verified by proving that it is an integral of the equation for helicity density.

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25

Novikov, E. A. "Self-amplification of turbulent 3D vorticity field and 2D vorticity gradient." Journal of Physics A: Mathematical and General 25, no. 11 (June 7, 1992): L657—L660. http://dx.doi.org/10.1088/0305-4470/25/11/007.

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26

Viúdez, Álvaro. "The Relation between Beltrami's Material Vorticity and Rossby–Ertel's Potential Vorticity." Journal of the Atmospheric Sciences 58, no. 17 (September 2001): 2509–17. http://dx.doi.org/10.1175/1520-0469(2001)058<2509:trbbmv>2.0.co;2.

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27

Wang, Xiuming, Xiaogang Zhou, Zuyu Tao, and Hua Liu. "Discussion on the complete-form vorticity equation and slantwise vorticity development." Journal of Meteorological Research 30, no. 1 (February 2016): 67–75. http://dx.doi.org/10.1007/s13351-016-5040-3.

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28

Sousa, E., and I. J. Sobey. "Effect of boundary vorticity discretization on explicit stream-function vorticity calculations." International Journal for Numerical Methods in Fluids 49, no. 4 (2005): 371–93. http://dx.doi.org/10.1002/fld.1001.

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Markowski, Paul M. "An Idealized Numerical Simulation Investigation of the Effects of Surface Drag on the Development of Near-Surface Vertical Vorticity in Supercell Thunderstorms." Journal of the Atmospheric Sciences 73, no. 11 (October 14, 2016): 4349–85. http://dx.doi.org/10.1175/jas-d-16-0150.1.

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Abstract Idealized simulations are used to investigate the contributions of frictionally generated horizontal vorticity to the development of near-surface vertical vorticity in supercell storms. Of interest is the relative importance of barotropic vorticity (vorticity present in the prestorm environment), baroclinic vorticity (vorticity that is principally generated by horizontal buoyancy gradients), and viscous vorticity (vorticity that originates from the subgrid-scale turbulence parameterization, wherein the effects of surface drag reside), all of which can be advected, tilted, and stretched. Equations for the three partial vorticities are integrated in parallel with the model. The partial vorticity calculations are complemented by analyses of circulation following material circuits, which are often able to be carried out further in time because they are less susceptible to explosive error growth. Near-surface mesocyclones that develop prior to cold-pool formation (this only happens when the environmental vorticity is crosswise near the surface) are dominated by only barotropic vertical vorticity when the lower boundary is free slip, but both barotropic and viscous vertical vorticity when surface drag is included. Baroclinic vertical vorticity grows large once a cold pool is established, regardless of the lower boundary condition and, in fact, dominates at the time the vortices are most intense in all but one simulation (a simulation dominated early by a barotropic mode of vortex genesis that may not be relevant to real convective storms).

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30

Dahl, Johannes M. L. "Near-Ground Rotation in Simulated Supercells: On the Robustness of the Baroclinic Mechanism*." Monthly Weather Review 143, no. 12 (December 1, 2015): 4929–42. http://dx.doi.org/10.1175/mwr-d-15-0115.1.

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Abstract This study addresses the robustness of the baroclinic mechanism that facilitates the onset of surface rotation in supercells by using two idealized simulations with different microphysics parameterizations and by considering previous results. In particular, the importance of ambient crosswise vorticity relative to baroclinically generated vorticity in the development of near-ground cyclonic vorticity is analyzed. The storms were simulated using the CM1 model in a kinematic base state characterized by a straight-line hodograph. A trajectory analysis spanning about 30 min was performed for a large number of parcels that contribute to near-surface vertical-vorticity maxima. The vorticity along these trajectories was decomposed into barotropic and nonbarotropic parts, where the barotropic vorticity represents the effects of the preexisting, substantially crosswise horizontal storm-relative vorticity. The nonbarotropic part represents the vorticity produced baroclinically within the storm. It was found that the imported barotropic vorticity attains a downward component near the surface, while the baroclinic vorticity points upward and dominates. This dominance of the baroclinic vorticity is independent of whether a single-moment or double-moment microphysics parameterization is used. A scaling argument is offered as explanation, predicting that the baroclinic vertical vorticity becomes increasingly dominant as downdraft strength increases.

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31

Airapetian, V. S. "Surface Magnetic Fields in Early-Type Stars." International Astronomical Union Colloquium 175 (2000): 334–36. http://dx.doi.org/10.1017/s0252921100056098.

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AbstractRecent observations imply magnetic activity in atmospheres of early-type stars. We explore the possibility that stressed surface magnetic fields can be driven by inertial oscillations, such as r-modes which are vorticity waves. We show that vorticIAL MOTIOns are able to supply helicity to drive magnetic activity in stellar atmospheres.

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LUNDGREN, THOMAS, and PETROS KOUMOUTSAKOS. "On the generation of vorticity at a free surface." Journal of Fluid Mechanics 382 (March 10, 1999): 351–66. http://dx.doi.org/10.1017/s0022112098003978.

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The mechanism for the generation of vorticity at a viscous free surface is described. This is a free-surface analogue of Lighthill's strategy for determining the vorticity flux at solid boundaries. In this method the zero-shear-stress and pressure boundary conditions are transformed into a boundary integral formulation suitable for the velocity–vorticity description of the flow. A vortex sheet along the free surface is determined by the pressure boundary condition, while the condition of zero shear stress determines the vorticity at the surface. In general, vorticity is generated at free surfaces whenever there is flow past regions of surface curvature. It is shown that vorticity is conserved in free-surface viscous flows. Vorticity which flows out of the fluid across the free surface is gained by the vortex sheet; the integral of vorticity over the entire fluid region plus the integral of ‘surface vorticity’ over the free surface remains constant. The implications of the present strategy as an algorithm for numerical calculations are discussed.

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33

Hsu, H. C., C. Kharif, M. Abid, and Y. Y. Chen. "A nonlinear Schrödinger equation for gravity–capillary water waves on arbitrary depth with constant vorticity. Part 1." Journal of Fluid Mechanics 854 (September 3, 2018): 146–63. http://dx.doi.org/10.1017/jfm.2018.627.

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A nonlinear Schrödinger equation for the envelope of two-dimensional gravity–capillary waves propagating at the free surface of a vertically sheared current of constant vorticity is derived. In this paper we extend to gravity–capillary wave trains the results of Thomas et al. (Phys. Fluids, 2012, 127102) and complete the stability analysis and stability diagram of Djordjevic & Redekopp (J. Fluid Mech., vol. 79, 1977, pp. 703–714) in the presence of vorticity. The vorticity effect on the modulational instability of weakly nonlinear gravity–capillary wave packets is investigated. It is shown that the vorticity modifies significantly the modulational instability of gravity–capillary wave trains, namely the growth rate and instability bandwidth. It is found that the rate of growth of modulational instability of short gravity waves influenced by surface tension behaves like pure gravity waves: (i) in infinite depth, the growth rate is reduced in the presence of positive vorticity and amplified in the presence of negative vorticity; (ii) in finite depth, it is reduced when the vorticity is positive and amplified and finally reduced when the vorticity is negative. The combined effect of vorticity and surface tension is to increase the rate of growth of modulational instability of short gravity waves influenced by surface tension, namely when the vorticity is negative. The rate of growth of modulational instability of capillary waves is amplified by negative vorticity and attenuated by positive vorticity. Stability diagrams are plotted and it is shown that they are significantly modified by the introduction of the vorticity.

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Boyer, Christian H., and Johannes M. L. Dahl. "The Mechanisms Responsible for Large Near-Surface Vertical Vorticity within Simulated Supercells and Quasi-Linear Storms." Monthly Weather Review 148, no. 10 (October 1, 2020): 4281–97. http://dx.doi.org/10.1175/mwr-d-20-0082.1.

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AbstractDespite their structural differences, supercells and quasi-linear convective systems (QLCS) are both capable of producing severe weather, including tornadoes. Previous research has highlighted multiple potential mechanisms by which horizontal vorticity may be reoriented into the vertical at low levels, but it is not clear in which situation what mechanism dominates. In this study, we use the CM1 model to simulate three different storm modes, each of which developed relatively large near-surface vertical vorticity. Using forward-integrated parcel trajectories, we analyze vorticity budgets and demonstrate that there seems to be a common mechanism for maintaining the near-surface vortices across storm structures. The parcels do not acquire vertical vorticity until they reach the base of the vortices. The vertical vorticity results from vigorous upward tilting of horizontal vorticity and simultaneous vertical stretching. While the parcels analyzed in our simulations do have a history of descent, they do not acquire appreciable vertical vorticity during their descent. Rather, during the analysis period relatively large horizontal vorticity develops as a result of horizontal stretching, and therefore this vorticity can be effectively tilted into the vertical.

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Rotunno, Richard, Paul M. Markowski, and George H. Bryan. "“Near Ground” Vertical Vorticity in Supercell Thunderstorm Models." Journal of the Atmospheric Sciences 74, no. 6 (May 15, 2017): 1757–66. http://dx.doi.org/10.1175/jas-d-16-0288.1.

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Abstract Numerical models of supercell thunderstorms produce near-ground rotation about a vertical axis (i.e., vertical vorticity) after the development of rain-cooled outflows and downdrafts. The physical processes involved in the production of near-ground vertical vorticity in simulated supercells have been a subject of discussion in the literature for over 30 years. One cause for this lengthy discussion is the difficulty in applying the principles of inviscid vorticity dynamics in a continuous fluid to the viscous evolution of discrete Eulerian simulations. The present paper reports on a Lagrangian analysis of near-ground vorticity from an idealized-supercell simulation with enhanced vertical resolution near the lower surface. The parcel that enters the low-level maximum of vertical vorticity has a history of descent during which its horizontal vorticity is considerably enhanced. In its final approach to this region, the parcel’s enhanced horizontal vorticity is tilted to produce vertical vorticity, which is then amplified through vertical stretching as the parcel rises. A simplified theoretical model is developed that exhibits these same features. The principal conclusion is that vertical vorticity at the parcel’s nadir (its lowest point), although helpful, does not need to be positive for rapid near-surface amplification of vertical vorticity.

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36

Hokenson, Gustave J. "Vorticity with variable viscosity." AIAA Journal 24, no. 6 (June 1986): 1039–40. http://dx.doi.org/10.2514/3.9384.

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37

Keen, Jeffrey S. "Consciousness, Vorticity, and Dipoles." World Futures 62, no. 5 (July 2006): 349–60. http://dx.doi.org/10.1080/02604020600752053.

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38

Salomaa, Martti M. "Quantized Vorticity in Superfluid3He." Physica Scripta T29 (January 1, 1989): 301–5. http://dx.doi.org/10.1088/0031-8949/1989/t29/059.

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39

Huang, Kerson. "Quantum vorticity in nature." International Journal of Modern Physics A 30, no. 25 (September 9, 2015): 1530056. http://dx.doi.org/10.1142/s0217751x15300562.

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Quantum vorticity occurs in superfluidity, which arises from a spatial variation of the quantum phase. As such, it can occur in diverse systems over a wide range of scales, from the electroweak sector and QCD of the standard model of particle theory, through the everyday world, to the cosmos. I review the observable manifestations, and their unified description in terms of an order parameter that is a complex scalar field.

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40

Davis, Christopher A. "Piecewise Potential Vorticity Inversion." Journal of the Atmospheric Sciences 49, no. 16 (August 1992): 1397–411. http://dx.doi.org/10.1175/1520-0469(1992)049<1397:ppvi>2.0.co;2.

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41

Keffer, Thomas. "The potential of vorticity." Nature 334, no. 6178 (July 1988): 105–6. http://dx.doi.org/10.1038/334105a0.

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42

Wang, Yalin, and A. Jacob Odgaard. "Flow control with vorticity." Journal of Hydraulic Research 31, no. 4 (July 1993): 549–62. http://dx.doi.org/10.1080/00221689309498877.

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43

Borich, M. A., and L. Friedland. "Driven chirped vorticity holes." Physics of Fluids 20, no. 8 (August 2008): 086602. http://dx.doi.org/10.1063/1.2964361.

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44

Barcilon, A., and P. G. Drazin. "Nonlinear Waves of Vorticity." Studies in Applied Mathematics 106, no. 4 (May 2001): 437–79. http://dx.doi.org/10.1111/1467-9590.00174.

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45

Stern, Melvin E., and Lawrence J. Pratt. "Dynamics of vorticity fronts." Journal of Fluid Mechanics 161, no. -1 (December 1985): 513. http://dx.doi.org/10.1017/s0022112085003032.

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46

Davis, R. L. "Quantum nucleation of vorticity." Physica B: Condensed Matter 178, no. 1-4 (May 1992): 76–82. http://dx.doi.org/10.1016/0921-4526(92)90181-q.

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47

Goode, Stephen W. "Vorticity and isotropic singularities." General Relativity and Gravitation 19, no. 11 (November 1987): 1075–82. http://dx.doi.org/10.1007/bf00759143.

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48

Kang, Y., and J. M. Vanden-Broeck. "Stern waves with vorticity." ANZIAM Journal 43, no. 3 (January 2002): 321–32. http://dx.doi.org/10.1017/s1446181100012542.

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Abstract:

AbstractSteady two-dimensional free surface flow past a semi-infinite flat plate is considered. The vorticity in the flow is assumed to be constant. For large values of the Froude number F, an analytical relation between F, the vorticity parameter ω and the steepness s of the waves in the far field is derived. In addition numerical solutions are calculated by a boundary integral equation method.

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49

McTaggart-Cowan, R., J. R. Gyakum, and M. K. Yau. "Moist Component Potential Vorticity." Journal of the Atmospheric Sciences 60, no. 1 (January 2003): 166–77. http://dx.doi.org/10.1175/1520-0469(2003)060<0166:mcpv>2.0.co;2.

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50

Dhont, Jan K. G., and Wim J. Briels. "Gradient and vorticity banding." Rheologica Acta 47, no. 3 (February 21, 2008): 257–81. http://dx.doi.org/10.1007/s00397-007-0245-0.

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Journal articles on the topic 'Vorticity'

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