scholarly journals Improved Measurements of the Sun’s Meridional Flow and Torsional Oscillation from Correlation Tracking on MDI and HMI Magnetograms

2021 ◽  
Vol 917 (2) ◽  
pp. 100
Author(s):  
Sushant S. Mahajan ◽  
David H. Hathaway ◽  
Andrés Muñoz-Jaramillo ◽  
Petrus C. Martens
Keyword(s):  
Torsional Oscillation ◽  
Meridional Flow ◽  
Correlation Tracking

Flow Driven by a Torsionally-Oscillating Shrouded Endwall Disk

1997 ◽  
Vol 119 (1) ◽  
pp. 115-121 ◽  
Author(s):  
Tae Gyu Lim ◽  
Jae Min Hyun
Keyword(s):  
Numerical Solutions ◽  
Stokes Equations ◽  
Torsional Oscillation ◽  
Numerical Data ◽  
Finite Geometry ◽  
Meridional Flow ◽  
Numerical Results ◽  
Navier Stokes ◽  
Steady Streaming ◽  
Dependent Flow

A study is made of time-dependent flow of a viscous fluid driven by an oscillating shrouded disk in finite geometry. Numerical solutions to the Navier-Stokes equations are obtained for the flow in a cylindrical cavity with its upper endwall disk executing torsional oscillation at a velocity Ω cos λt. Details of the three-component velocity field are examined at high Reynolds number. The value of the nondimensional amplitude of disk oscillation, ε = Ω/λ, encompasses a range up to ε ≳ O(1). The numerical results for the azimuthal flow for ε ≪ 1 are consistent with the predictions of the earlier analytical model. The azimuthal flow is largely confined to the Stokes layer thickness. The analytical predictions of the meridional flow, based on a straightforward expansion technique, display discrepancies from the numerical results. The steady meridional streaming at finite values of ε is exhibited. The qualitative patterns of meridional steady streaming are verified by laboratory flow visualizations. The explicit effect of Re on the overall flow character is scrutinized. The numerical data are processed to describe the behavior of the torque coefficient at the oscillating disk.

Fore-Aft Forces in Tire-Wheel Assemblies Generated by Unbalances and the Influence of Balancing

1991 ◽  
Vol 19 (3) ◽  
pp. 142-162 ◽  
Author(s):  
D. S. Stutts ◽  
W. Soedel ◽  
S. K. Jha
Keyword(s):  
Mathematical Model ◽  
Elastic Foundation ◽  
Torsional Oscillation ◽  
Vertical Direction ◽  
Torsional Stiffness ◽  
Rolling Motion ◽  
Vertical Force ◽  
Horizontal Force ◽  
Wheel Rim ◽  
Open Question

Abstract When measuring bearing forces of the tire-wheel assembly during drum tests, it was found that beyond certain speeds, the horizontal force variations or so-called fore-aft forces were larger than the force variations in the vertical direction. The explanation of this phenomenon is still somewhat an open question. One of the hypothetical models argues in favor of torsional oscillations caused by a changing rolling radius. But it appears that there is a simpler answer. In this paper, a mathematical model of a tire consisting of a rigid tread ring connected to a freely rotating wheel or hub through an elastic foundation which has radial and torsional stiffness was developed. This model shows that an unbalanced mass on the tread ring will cause an oscillatory rolling motion of the tread ring on the drum which is superimposed on the nominal rolling. This will indeed result in larger fore-aft than vertical force variations beyond certain speeds, which are a function of run-out. The rolling motion is in a certain sense a torsional oscillation, but postulation of a changing rolling radius is not necessary for its creation. The model also shows the limitation on balancing the tire-wheel assembly at the wheel rim if the unbalance occurs at the tread band.

scholarly journals Verification of the helioseismic Fourier-Legendre analysis for meridional flow measurements

2016 ◽  
Vol 592 ◽  
pp. A106 ◽  
Author(s):  
M. Roth ◽  
H.-P. Doerr ◽  
T. Hartlep
Keyword(s):  
Meridional Flow ◽  
Flow Measurements

Correlation Tracking with Correcting and Adaptive Update Strategy

2019 ◽  
Vol 14 (5) ◽  
pp. 2181-2190
Author(s):  
Shao-Hu Peng ◽  
Hyun-Do Nam
Keyword(s):  
Correlation Tracking ◽  
Update Strategy

Viscous dissipation of Rankine vortex profile in zero meridional flow

2005 ◽  
Vol 21 (6) ◽  
pp. 550-556 ◽  
Author(s):  
Yasser Aboelkassem ◽  
Georgios H. Vatistas ◽  
Nabil Esmail
Keyword(s):  
Viscous Dissipation ◽  
Meridional Flow ◽  
Rankine Vortex

Non-linear torsional oscillation of a two-degree-of-freedom system incorporating a Hooke joint

1964 ◽  
Vol 277 (1368) ◽  
pp. 92-106 ◽  
Keyword(s):  
Large Amplitude ◽  
Critical Speed ◽  
Torsional Oscillation ◽  
Degree Of Freedom ◽  
Non Linear ◽  
Two Degree Of Freedom

The non-linear torsional oscillation of the system is analyzed by means of a variant of Kryloff and Bogoliuboff’s method. It is shown that each mode of the system can perform oscillations of large amplitude in a number of critical speed ranges, and that hysteresis effects and discontinuous jumps in amplitude are to be expected in these speed ranges if the damping is light.

Torsional oscillation of rigid disk in infinite transversely isotropic elastic cylinder

2006 ◽  
Vol 27 (7) ◽  
pp. 911-917 ◽  
Author(s):  
Sakti Pada Barik ◽  
Mridula Kanoria ◽  
P. K. Chaudhuri
Keyword(s):  
Torsional Oscillation ◽  
Transversely Isotropic ◽  
Elastic Cylinder ◽  
Rigid Disk
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