Dynamics of the Slanted Cylinder Afterbody Vortices

Zigunov, Fernando; Sellappan, Prabu; Alvi, Farrukh S.

doi:10.2514/6.2020-1322

Cited by 8 publications

(4 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this work, we have presented a new and improved method for vortex identification, based on the previously proposed Γ method (Graftieaux et al 2001). The CGM (Zigunov et al 2020) was extended to provide Γ 2 functions, and the CGM was used to develop the AGM. We have proved that the CGM is mathematically the same as the Γ method and that the AGM provides similar maps to the CGM.…”

Section: Discussionmentioning

confidence: 99%

“…The discrete Γ 1 function for the 2D convolution version of the Γ method (hereafter CGM) wasproposed by Zigunov et al (2020):…”

Section: Vortex Identification With the Convolution γ Methodsmentioning

confidence: 99%

“…x PM y PM Thus, the two convolutions in Equation (4) can be represented as multiplications of convolution kernels by the sines and cosines of the angles between the vectors U M and the x-axis, i.e., ( ) q sin U M and ( ) q cos U M , respectively (see Zigunov et al 2020, for more details). Therefore, this equation can be rewritten as…”

Section: Vortex Identification With the Convolution γ Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Advanced Γ Method for Small-scale Vortex Detection in the Solar Atmosphere

Yuan,

de Souza e Almeida Silva,

Fedun

et al. 2023

ApJS

View full text Add to dashboard Cite

Ubiquitous vortical structures are considered to act as a natural source of various solar plasma phenomena, for example, a wide range of magnetohydrodynamic waves and jet excitations. This work aims to develop an advanced vortex detection algorithm based on the Γ method and using a separable convolution kernel technique. This method is applied to detect and analyze the photospheric vortices in 3D realistic magnetoconvection numerical and observational data. We present the advanced Γ method (AGM), and our results indicate that the AGM performs with better accuracy in comparison with the original Γ method. The AGM allows us to identify small- and large-scale vortices with no vortex interposition and without requiring the changing of the threshold. In this way, the nondetection issue is mostly prevented. It was found that the Γ method failed to identify the large and longer-lived vortices, which were detected by the AGM. The size of the detected vortical structures tends to vary over time, with most vortices shrinking toward their end. The vorticity at the center is also not constant, presenting a sharp decay as the vortex ceases to exist. Due to its capability of identifying vortices with minimum nondetection, the vortex properties—such as lifetime, geometry, and dynamics—are better captured by the AGM than by the Γ method. In this era of new high-resolution observation, the AGM can be used as a precise technique for identifying and performing statistical analysis of solar atmospheric vortices.

show abstract

Section: Discussionmentioning

confidence: 99%

“…The discrete Γ 1 function for the 2D convolution version of the Γ method (hereafter CGM) wasproposed by Zigunov et al (2020):…”

Section: Vortex Identification With the Convolution γ Methodsmentioning

confidence: 99%

Section: Vortex Identification With the Convolution γ Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Advanced Γ Method for Small-scale Vortex Detection in the Solar Atmosphere

Yuan,

de Souza e Almeida Silva,

Fedun

et al. 2023

ApJS

View full text Add to dashboard Cite

show abstract

“… a H vortex / H packed is the average height of the two symmetric vortex cores scaled by the height of the packed bed. Based on the time-averaged solid volumetric flux field, the heights of the vortex are identified by the algorithms proposed by Zigunov et al The values in the brackets are relative errors compared with real particle simulation. …”

Section: A Posteriori Analysismentioning

confidence: 99%

Improvement of the Coarse-Grained Discrete Element Method for Frictional Particles

Chen

et al. 2021

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

The coarse-grained discrete element method (CGDEM) is promising for its ability to reduce computational cost. However, compared with discrete element method (DEM), CGDEM often overpredicts the granular temperature in simulations of systems with frictional particles. This is partially due to the fact that traditional coarsening strategies only account for the correction to energy dissipation due to inelastic collisions. This work proposes two types of new coarsening strategies that also make the correction to energy dissipation caused by the frictional force between particles. CGDEM simulations of homogeneous cooling systems (HCSs) and two bubbling fluidized beds are executed to evaluate the performance of the proposed strategies. It is found that, relative to CGDEM with traditional coarsening strategies, CGDEM with the proposed strategies gives a more accurate prediction of the instantaneous granular temperature in HCSs. They also better reproduce the time-averaged fields obtained by DEM simulations for the considered bubbling fluidized beds. This demonstrates the necessity of considering both inelastic and frictional origins of energy dissipation in the coarsening strategy.

show abstract