scholarly journals Spatio-Temporal Symmetry—Point Groups with Time Translations

Symmetry ◽  
2017 ◽  
Vol 9 (9) ◽  
pp. 187 ◽  
Author(s):  
Haricharan Padmanabhan ◽  
Maggie Kingsland ◽  
Jason Munro ◽  
Daniel Litvin ◽  
Venkatraman Gopalan
Keyword(s):  
Symmetry Point ◽  
Point Groups ◽  
Spatio Temporal ◽  
Temporal Symmetry

Spatio-temporal symmetry – crystallographic point groups with time translations and time inversion

2018 ◽  
Vol 74 (4) ◽  
pp. 399-402 ◽  
Author(s):  
Vincent S. Liu ◽  
Brian K. VanLeeuwen ◽  
Jason M. Munro ◽  
Haricharan Padmanabhan ◽  
Ismaila Dabo ◽  
...  
Keyword(s):  
General Position ◽  
Point Group ◽  
Time Inversion ◽  
Time Translation ◽  
Crystallographic Symmetry ◽  
Point Groups ◽  
Spatio Temporal ◽  
Time Periodic ◽  
Temporal Symmetry

The crystallographic symmetry of time-periodic phenomena has been extended to include time inversion. The properties of such spatio-temporal crystallographic point groups with time translations and time inversion are derived and one representative group from each of the 343 types has been tabulated. In addition, stereographic symmetry and general-position diagrams are given for each representative group. These groups are also given a notation consisting of a short Hermann–Mauguin magnetic point-group symbol with each spatial operation coupled with its associated time translation.

Fullerenes C20-C60: Combinatorial types and symmetry point groups

2002 ◽  
Vol 47 (5) ◽  
pp. 720-722 ◽  
Author(s):  
Yu. L. Voytekhovsky ◽  
D. G. Stepenshchikov
Keyword(s):  
Symmetry Point ◽  
Point Groups

scholarly journals Disrupting the spatio-temporal symmetry of the electron dynamics in atmospheric pressure plasmas by voltage waveform tailoring

2019 ◽  
Vol 28 (1) ◽  
pp. 01LT01 ◽  
Author(s):  
Andrew R Gibson ◽  
Zoltán Donkó ◽  
Layla Alelyani ◽  
Lena Bischoff ◽  
Gerrit Hübner ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Electron Dynamics ◽  
Voltage Waveform ◽  
Atmospheric Pressure Plasmas ◽  
Spatio Temporal ◽  
Temporal Symmetry

Notiz: Quantification of Symmetry

1996 ◽  
Vol 51 (7) ◽  
pp. 882-883
Author(s):  
Igor Novak
Keyword(s):  
Finite Groups ◽  
Group Element ◽  
Symmetry Point ◽  
Point Groups ◽  
New Criterion

Abstract A new mathematical criterion is suggested for symmetry ranking, i.e. determination of an “absolute symmetry scale” for discrete, finite groups. The criterion is based on both, the periods (orders) of each group element and the order of the group itself. This is different from the current criteria which consider only the orders of the groups themselves. The symmetry ranking, based on the new criterion, is applied to the symmetry point groups.

scholarly journals Mode competition in modulated Taylor–Couette flow

2008 ◽  
Vol 601 ◽  
pp. 381-406 ◽  
Author(s):  
M. AVILA ◽  
M. J. BELISLE ◽  
J. M. LOPEZ ◽  
F. MARQUES ◽  
W. S. SARIC
Keyword(s):  
Couette Flow ◽  
Physical Experiment ◽  
Mode Competition ◽  
Taylor Vortex ◽  
Coexistence Region ◽  
Narrow Region ◽  
Taylor Couette ◽  
Spatio Temporal ◽  
Temporal Symmetry ◽  
Taylor Couette Flow

The effects of harmonically oscillating the inner cylinder about a zero mean rotation in a Taylor–Couette flow are investigated experimentally and numerically. The resulting time-modulated circular Couette flow possesses a Z2 spatio-temporal symmetry which gives rise to two distinct modulated Taylor vortex flows. These flows are initiated at synchronous bifurcations, have the same spatial symmetries, but are characterized by different spatio-temporal symmetries and axial wavenumber. Mode competition between these two states has been investigated in the region where they bifurcate simultaneously. In the idealized numerical model, the two flows have been found to coexist and be stable in a narrow region of parameter space. However, in the physical experiment, neither state has been observed in the coexistence region. Instead, we observe noise-sustained flows with irregular time-dependent axial wavenumber. Movies are available with the online version of the paper.

Flow over a thin circular disk at low to moderate Reynolds numbers

2008 ◽  
Vol 605 ◽  
pp. 253-262 ◽  
Author(s):  
A. R. SHENOY ◽  
C. KLEINSTREUER
Keyword(s):  
Lift Coefficient ◽  
Three Dimensional ◽  
Circular Disk ◽  
Vortex Structures ◽  
Separation Region ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Vortex Loops ◽  
Spatio Temporal ◽  
Temporal Symmetry

Computation of viscous flow over a circular disk of aspect ratio 10 (thickness/diameter) in the Reynolds number (Re) range of 10 to 300 was performed. The following flow regimes were observed: (I) steady axisymmetric flow when Re < 135, with the presence of a toroidal vortex behind the disk; (II) regular bifurcation with loss of azimuthal symmetry but with planar symmetry and a double-threaded wake, for 135 ≤ Re < 155; (III) three-dimensional flow with periodic shedding of double-sided hairpin-shaped vortex structures and periodic motion of the separation region for 155 ≤ Re < 172; (IV) regular shedding of double-sided hairpin-shaped vortex structures with planar and spatio-temporal symmetry for 172 ≤ Re < 280; (V) periodic three-dimensional flow with irregular rotation of the separation region when Re = 280–300. This transition process for the disk differs from that for the sphere as we observe a loss of the symmetry plane in Regime III due to a twisting motion of the axial vorticity strands in the wake of the disk. The periodic flow was characterized by double-sided hairpin structures, unlike the one-sided vortex loops observed for the sphere. This resulted in the drag coefficient oscillating at twice the frequency of the axial velocity. In Regime IV, the vortex loops were shed from diametrically opposite locations and with equal strength, resulting in the lift coefficient oscillating symmetrically about a zero mean. These results imply the presence of spatio-temporal symmetry.

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