The flow structures of a transversely rotating sphere at high rotation rates

Dobson, J.; Ooi, Andrew; Poon, Eric

doi:10.1016/j.compfluid.2014.07.001

Cited by 19 publications

(8 citation statements)

References 32 publications

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“…The importance of orientation with respect to the background flow for ellipsoidal (or any nonspherical) particles is underlined by the fact that particle-transport in most natural and industrial systems is a combination of particle translation and rotation [20,5]. Particles in these systems could rotate due to collision with other particles and the walls, or due to presence of high vorticity and mean shear of the fluid.…”

Section: Introductionmentioning

confidence: 99%

“…With the increase of computing power, fully resolved simulations (DNS and high-resolution LES) have become the primary tool to study the dynamics of rotating particles. [20,31,32].…”

Section: Introductionmentioning

confidence: 99%

“…In Section 2, the numerical method and the setup for the simulations have been described, particularly focusing on the moving nonconforming Schwarz-spectral element method (Schwarz-SEM) framework. In Section 3 the simulation results are discussed, first focusing on validation against existing DNS of a rotating sphere [20], and then illustrating the results from the rotating ellipsoidal cases. In Section 4, the combined effect of rotation and shape of the ellipsoid on the drag and lift is discussed and compared with several nonrotating configurations.…”

Section: Introductionmentioning

confidence: 99%

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Direct Numerical Simulation of Rotating Ellipsoidal Particles using Moving Nonconforming Schwarz-Spectral Element Method

Mittal,

Dutta,

Fischer

2019

Preprint

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We present application of a highly-scalable overlapping grid-based nonconforming Schwarz-spectral element method (Schwarz-SEM) to study the dynamics of rotating ellipsoidal particles. The current study is one of the first to explore the effect of rotation on ellipsoidal particles using fully resolved simulations (direct numerical simulation). The rotating ellipsoidal particles show substantial difference in the dynamics of the flow, when compared against non-rotating particles. The difference is primarily due to periodic attachment and separation of the flow to the surface of the particle for the rotating cases, which results in a higher drag on the particles when compared to the corresponding non-rotating cases. The dynamics is also different from a rotating spherical particle, where a steady shear layer develops near the surface of the sphere. For the rotating ellipsoidal particles, this mechanism results in a phase-difference between the position of observed maximum and minimum drag, and the position of expected maximum and minimum drag (i.e., maximum and minimum projected area). A similar phase-difference is also observed for the lift acting on the rotating ellipsoidal particles. The results presented here demonstrate the importance of explicitly modeling the shape and rotation of particles when we study the dynamics of non-spherical particles. Finally, the study also validates the use of nonconforming Schwarz-SEM for tackling problems in fully resolved particulate flow dynamics.

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Section: Introductionmentioning

confidence: 99%

“…With the increase of computing power, fully resolved simulations (DNS and high-resolution LES) have become the primary tool to study the dynamics of rotating particles. [20,31,32].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Direct Numerical Simulation of Rotating Ellipsoidal Particles using Moving Nonconforming Schwarz-Spectral Element Method

Mittal,

Dutta,

Fischer

2019

Preprint

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“…Spheres. Previous numerical investigations (Kim 2009, Giacobello et al 2009, Dobson et al 2014, Rajamuni et al 2018 on the effects of rotation on the wakes of rigidly mounted rotating spheres at low Reynolds numbers (Re ≤ 1000) have revealed considerable wake modifications and even suppression of the vortex shedding, depending on rotation rate. In comparison with the cylinder case, the wake structure is more strongly affected at lower rotation rates, with Figure 4b showing that a broad change occurs beyond α 0.7.…”

Section: Subharmonicmentioning

confidence: 99%

Bluff Bodies and Wake–Wall Interactions

Thompson

Leweke

Hourigan

2021

Annu. Rev. Fluid Mech.

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This review surveys the dramatic variations in wake structures and flow transitions, in addition to body forces, that appear as the motion of bluff bodies through a fluid occurs increasingly closer to a solid wall. In particular, we discuss the two cases of bluff bodies translating parallel to solid walls at varying heights and bluff bodies impacting on solid walls. In the former case, we highlight the changes to the wake structures as the flow varies from that of an isolated body to that of a body on or very close to the wall, including the effects when the body is rotating. For the latter case of an impacting body, we review the flow structures following impact and their transition to three-dimensionality. We discuss the issue of whether there is solid–solid contact between the bluff body and a wall and its importance to body motion. Expected final online publication date for the Annual Review of Fluid Mechanics, Volume 53 is January 6, 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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“…1(a) because the boundary layer separation is delayed on the upper surface and occurs earlier on the lower surface. The magnitude of the Magnus force (18) is mainly a function of the rate of spin (19) , the flight velocity and the geometry of the body, with secondary effects arising from sideslip angle and surface roughness (20) .…”

Section: Magnus Effectmentioning

confidence: 99%

Experimental determination of the aerodynamic coefficients of spinning bodies

Nguyen¹,

Corey²,

Chan³

et al. 2019

Aeronaut. j.

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To accurately predict the probabilities of impact damage to aircraft from runway debris, it is important to understand and quantify the aerodynamic forces that contribute to runway debris lofting. These lift and drag forces were therefore measured in experiments with various bodies spun over a range of angular velocities and Reynolds numbers. For a smooth sphere, the Magnus effect was observed for ratios of spin speed to flow speed between 0.3 and 0.4, but a negative Magnus force was observed at high Reynolds numbers as a transitional boundary layer region was approached. Similar relationships between lift and spin rate were found for both cube- and cylinder-shaped test objects, particularly with a ratio of spin speed to flow speed above 0.3, which suggested comparable separation patterns between rapidly spinning cubes and cylinders. A tumbling smooth ellipsoid had aerodynamic characteristics similar to that of a smooth sphere at a high spin rate. Surface roughness in the form of attached sandpaper increased the average lift on the cylinder by 24%, and approximately doubled the lift acting on the ellipsoid in both rolling and tumbling configurations.

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The flow structures of a transversely rotating sphere at high rotation rates

Cited by 19 publications

References 32 publications

Direct Numerical Simulation of Rotating Ellipsoidal Particles using Moving Nonconforming Schwarz-Spectral Element Method

Direct Numerical Simulation of Rotating Ellipsoidal Particles using Moving Nonconforming Schwarz-Spectral Element Method

Bluff Bodies and Wake–Wall Interactions

Experimental determination of the aerodynamic coefficients of spinning bodies

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