Orbitally shaken shallow fluid layers. I. Regime classification

Alpresa, Paola; Sherwin, Spencer J.; Weinberg, Peter D.; Reeuwijk, Maarten van

doi:10.1063/1.4996916

Cited by 17 publications

(34 citation statements)

References 43 publications

(6 reference statements)

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“…An improved approach has recently been presented by Alpresa et al [ 31 , 34 ]. Termed the potential theory-Stokes (PT-Stokes) model, it divides the fluid into two layers.…”

Section: Characterisation Of Flow In Swirling Wellsmentioning

confidence: 99%

Understanding mechanobiology in cultured endothelium: A review of the orbital shaker method

Warboys¹,

Ghim²,

Weinberg

2019

Atherosclerosis

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A striking feature of atherosclerosis is its highly non-uniform distribution within the arterial tree. This has been attributed to variation in the haemodynamic wall shear stress (WSS) experienced by endothelial cells, but the WSS characteristics that are important and the mechanisms by which they lead to disease remain subjects of intensive investigation despite decades of research. In vivo evidence suggests that multidirectional WSS is highly atherogenic. This possibility is increasingly being studied by culturing endothelial cells in wells that are swirled on an orbital shaker. The method is simple and cost effective, has high throughput and permits chronic exposure, but interpretation of the results can be difficult because the fluid mechanics are complex; hitherto, their description has largely been restricted to the engineering literature. Here we review the findings of such studies, which indicate that putatively atherogenic flow characteristics occur at the centre of the well whilst atheroprotective ones occur towards the edge, and we describe simple mathematical methods for choosing experimental variables that avoid resonance, wave breaking and uncovering of the cells. We additionally summarise a large number of studies showing that endothelium cultured at the centre of the well expresses more pro-inflammatory and fewer homeostatic genes, has higher permeability, proliferation, apoptosis and senescence, and shows more endothelial-to-mesenchymal transition than endothelium at the edge. This simple method, when correctly interpreted, has the potential to greatly increase our understanding of the homeostatic and pathogenic mechanobiology of endothelial cells and may help identify new therapeutic targets in vascular disease.

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“…An improved approach has recently been presented by Alpresa et al [ 31 , 34 ]. Termed the potential theory-Stokes (PT-Stokes) model, it divides the fluid into two layers.…”

Section: Characterisation Of Flow In Swirling Wellsmentioning

confidence: 99%

Understanding mechanobiology in cultured endothelium: A review of the orbital shaker method

Warboys¹,

Ghim²,

Weinberg

2019

Atherosclerosis

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“…This study uses the computational model and simulation case studies introduced in detail in Part 1 1 . The cases cover a wide range of flow behaviours including wave breaking, multicrest waves, and the bottom being uncovered.…”

Section: Simulationsmentioning

confidence: 99%

“…where the superscript St denotes "Stokes", a and ω are the radius and speed of rotation, respectively, and ρ and ν are the fluid density and kinetic viscosity, respectively. Equation (1) originates from the classic Stokes second problem configuration which consists of a half-space z > 0 bounded by a plate at z = 0 that oscillates uniaxially in its plane as v u = A cos(ωt)e x ,…”

Section: Introductionmentioning

confidence: 99%

Orbitally shaken shallow fluid layers. II. An improved wall shear stress model

et al. 2018

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A new model for the analytical prediction of wall shear stress distributions at the base of orbitally shaken shallow fluid layers is developed. This model is a generalisation of the classical extended Stokes solution and will be referred to as the PT-Stokes model. The model is validated using a large set of numerical simulations covering a wide range of flow regimes representative of those used in laboratory experiments. It is demonstrated that the model is in much better agreement with the simulation data than the classical Stokes solution, improving the prediction in 63% of the studied cases. The central assumption of the model-which is to link the wall shear stress with the surface velocity-is shown to hold remarkably well over all regimes covered. A MATLAB-implementation of the PT-Stokes model

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“…This property is beneficial for the application of linear wave theory, since the parameter space (d s ,Ω) of the linear regime is considerably increased. This argumentation is also underlined by the regime classification study conducted by Alpresa et al (2018a). They pointed out the importance of the Froude number (Fr), showing that linear waves are only excitable for sufficiently small Fr.…”

Section: Realization Of Phase-shift Measurements Using a Reference Dementioning

confidence: 81%

“…As a last point, we want to emphasize once more the expansion of the linear interfacial wave regime in comparison with forced one-layer free-surface wave systems, naturally broadening the applicability of linear wave theory. Alpresa et al (2018a) draw up a detailed regime classification of orbitally shaken free-surface waves. They provide a clear overview of all orbital shaking studies reviewed in the literature in cylindrical containers together with the applied system parameters.…”

Section: Applicability Of the Potential Modelmentioning

confidence: 99%

Measurement of interfacial wave dynamics in orbitally shaken cylindrical containers using ultrasound pulse-echo techniques

2019

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We present a novel experiment on interfacial wave dynamics in orbitally shaken cylindrical vessels containing two-and three fluid layers. The experiment was designed as a hydrodynamical model for both aluminum reduction cells and liquid metal batteries to gain new insights into the rotational wave motion driven by the metal pad roll instability. Different options are presented to realize stable and measurable multi-layer stratifications. We introduce a new acoustic measurement procedure allowing to reconstruct wave amplitudes also in opaque liquids by tracking ultrasonic pulse echoes reflected on the interfaces. Measurements of resonance curves and phase shifts were conducted for varying interface positions. A strong influence of the top and bottom walls were observed, considerably reducing wave amplitudes and eigenfrequencies, when the interface is getting close. Finally, measured resonance curves were successfully compared with an existing forced wave theory that we extended to two-layer interfacial waves. The comparison stresses the importance to carefully control the boundary condition at the contact line.

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Orbitally shaken shallow fluid layers. I. Regime classification

Cited by 17 publications

References 43 publications

Understanding mechanobiology in cultured endothelium: A review of the orbital shaker method

Understanding mechanobiology in cultured endothelium: A review of the orbital shaker method

Orbitally shaken shallow fluid layers. II. An improved wall shear stress model

Measurement of interfacial wave dynamics in orbitally shaken cylindrical containers using ultrasound pulse-echo techniques

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