Effects of granular additives on transition boundaries between flow states of rimming flows

1999 ◽  
Vol 11 (8) ◽  
pp. 2020-2029 ◽  
Author(s):  
O. A. M. Boote ◽  
P. J. Thomas
Keyword(s):  
2021 ◽  
Vol 910 ◽  
Author(s):  
Negar Hosseini ◽  
Martin D. Griffith ◽  
Justin S. Leontini
Keyword(s):  

Abstract


2021 ◽  
Vol 1067 (1) ◽  
pp. 012091
Author(s):  
H N Azziz ◽  
E Q Hussein ◽  
M A Abdulhameed

1966 ◽  
Vol 6 (6) ◽  
pp. 254-258 ◽  
Author(s):  
William Schumer
Keyword(s):  
Low Flow ◽  
Fat Cell ◽  

1996 ◽  
Vol 328 ◽  
pp. 345-407 ◽  
Author(s):  
C. H. K. Williamson

It is now well-known that the wake transition regime for a circular cylinder involves two modes of small-scale three-dimensional instability (modes A and B), depending on the regime of Reynolds number (Re), although almost no understanding of the physical origins of these instabilities, or indeed their effects on near-wake formation, have hitherto been made clear. We address these questions in this paper. In particular, it is found that the two different modes A and B scale on different physical features of the flow. Mode A has a larger spanwise wavelength of around 3–4 diameters, and scales on the larger physical structure in the flow, namely the primary vortex core. The wavelength for mode A is shown to be the result of an ‘elliptic instability’ in the nearwake vortex cores. The subsequent nonlinear growth of vortex loops is due to a feedback from one vortex to the next, involving spanwise-periodic deformation of core vorticity, which is then subject to streamwise stretching in the braid regios. This mode gives an out-of-phase streamwise vortex pattern.In contrast, mode-B instability has a distinctly smaller wavelength (1 diameter) which scales on the smaller physical structure in the flow, the braid shear layer. It is a manifestation of an instability in a region of hyperbolic flow. It is quite distinct from other shear flows, in that it depends on the reverse flow of the bluff-body wake; the presence of a fully formed streamwise vortex system, brought upstream from a previous half-cycle, in proximity to the newly evolving braid shear layer, leads to an in-phase stream-wise vortex array, in strong analogy with the ‘Mode 1’ of Meiburg & Lasheras (1988) for a forced unseparated wake. In mode B, we also observe amalgamation of streamwise vortices from a previous braid with like-sign vortices in the subsequent braid.It is deduced that the large scatter in previous measurements concerning mode A is due to the presence of vortex dislocations. Dislocations are triggered at the sites of some vortex loops of mode A, and represent a natural breakdown of the periodicity of mode A instability. By minimizing or avoiding the dislocations which occur from end contamination or which occur during wake transition, we find an excellent agreement of both critical Re and spanwise wavelength of mode A with the recent secondary stability analysis of Barkley & Henderson (1996).Wake transition is further characterized by velocity and pressure measurements. It is consistent that, when mode-A instability and large-scale dislocations appear, one finds a reduction of base suction, a reduction of (two-dimensional) Reynolds stress level, a growth in size of the formation region, and a corresponding drop in Strouhal frequency. Finally, the present work leads us to a new clarification of the possible flow states through transition. Right through this regime of Re, there exist two distinct and continuous Strouhal frequency curves: the upper one corresponds with purley small- scale instabilities (e.g. denoted as mode A), while the lower curve corresponds with a combination of small-scale plus dislocation structures (e.g. mode A*). However, some of the flow states are transient or ‘unstable’, and the natural transitioning wake appears to follow the scenario: (2D→A*→B).


Mindfulness ◽  
2021 ◽  
Author(s):  
Julianna M. Lynch ◽  
Allison S. Troy

Abstract Objectives The current study investigated the hypothesis that the relationship between flow states and well-being is mediated by nondual experiences. Past empirical and theoretical work suggests flow states share similarities with nondual experiences. The current study expanded upon previous work by examining the relationships between flow, nondual experiences, emotion, and well-being. Methods Students enrolled in various artistic classes (N = 104) were surveyed once a week for four weeks. Participants reported on their experiences of flow, nonduality, emotion, and psychological and subjective well-being. Results Higher scores on measures of both flow (b = 7.03, SE = 0.82, p < .001) and nondual experiences (b = 0.17, SE = 0.02, p < .001) predicted increased positive emotion immediately after class. Nondual experiences partially mediated this relationship, such that when accounting for nondual experiences, the relationship between flow and positive emotion was significantly decreased (b = 4.30, SE = 0.45, p < .001). Longitudinally, nondual experience also mediated the relationship between flow and satisfaction with life (Sobel t = 1.94, SE = 1.06, p = .05). However, while flow predicted increased psychological well-being (b = 0.32, SE = 0.14, p = .02) after the four weeks, nondual experience did not (b = −0.003, SE = 0.002, p = .13). Conclusions These findings suggest that flow states may facilitate some features of nonduality and share similarities with meditative states. Additionally, the link between flow and well-being may be explained by its similarities to meditative states, and that creative activities could be useful in fostering well-being.


2008 ◽  
Vol 597 ◽  
pp. 91-118 ◽  
Author(s):  
E. S. BENILOV ◽  
M. S. BENILOV ◽  
N. KOPTEVA

We examine steady flows of a thin film of viscous fluid on the inside of a cylinder with horizontal axis, rotating about this axis. If the amount of fluid in the cylinder is sufficiently small, all of it is entrained by rotation and the film is distributed more or less evenly. For medium amounts, the fluid accumulates on the ‘rising’ side of the cylinder and, for large ones, pools at the cylinder's bottom. The paper examines rimming flows with a pool affected by weak surface tension. Using the lubrication approximation and the method of matched asymptotics, we find a solution describing the pool, the ‘outer’ region, and two transitional regions, one of which includes a variable (depending on the small parameter) number of asymptotic zones.


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