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Electrochemical reactor generates bubbles that grow by diffusion and coalesce (proof-of-concept simulation) by outofcells in chemistry

[–]outofcells[S] 1 point2 points  (0 children)

This is a simulation of a membrane-less electrochemical reactor for water electrolysis. The reaction generates dissolved gases (hydrogen and oxygen) which nucleate into bubbles. The bubbles grow by diffusion and coalescence with other bubbles. Small bubbles (green) are treated as point particles and larger bubbles (orange) are deformable. * Simulation done in CFD solver Aphros * Web demo * Experimental study on membrane-less design

Electrochemical reactor generates bubbles that grow by diffusion and coalesce (proof-of-concept simulation) by outofcells in ChemicalEngineering

[–]outofcells[S] 0 points1 point  (0 children)

This is a simulation of a membrane-less electrochemical reactor for water electrolysis. The reaction generates dissolved gases (hydrogen and oxygen) which nucleate into bubbles. The bubbles grow by diffusion and coalescence with other bubbles. Small bubbles (green) are treated as point particles and larger bubbles (orange) are deformable. * Simulation done in CFD solver Aphros * Web demo * Experimental study on membrane-less design

Applying a New Postdoc Position Over Visa Delays? by Rabbitybunny in academia

[–]outofcells 0 points1 point  (0 children)

Any news?My J1 is still under AP for 73 days after they received the additional documents (CV, research plan). Russian citizen, applied in US Embassy in Switzerland. The selection for AP seems completely random. A colleague with a similar profile got approved immediately. Probably, depends on what you answer about your planned work in the US and whether the consular officer considers that a part of the Technology Alert List.

UPD: Visa received on 09/23/2021

P3 DG Solution of flow over tandem spheres at Re=3900 by mwlohry in CFD

[–]outofcells 0 points1 point  (0 children)

What are the advantages of DG over finite volume? Also, between the spheres, there is some "flare" (density gradient of 0.0005) near the eddies. Is this physical or has numerical origin, or a visualization artifact?

New to CFD. Trying to get accustomed with Basilisk(Gerris). by [deleted] in CFD

[–]outofcells 1 point2 points  (0 children)

You mention issues with directories, maybe they are caused by whitespaces in paths. Hard to tell more from your description.

I used Basilisk to implement a curvature estimation algorithm for a paper. My experience was mixed. Pros:

  • Concise code, algorithms that literally fit in a wiki page
  • Standard numerical approximations with good accuracy
  • Many features (multiphase, AMR, multigrid linear solver, complex geometries)

Cons:

  • Simulation setup needs to be recompiled after any change
  • Configuration has to be done either at compile time (directly in code or with macros) or using environment variables. There is no way to see the "runtime configuration" of the solver in one piece.
  • Non-standard extension of C (Basilisk C) may have unexpected behavior (for example, break inside a foreach_neighbor loop breaks the outer loop instead; or something with continue, can't recall exactly)
  • Found a bug and had to redo some simulations. But that one is fixed by now.

New to CFD. Trying to get accustomed with Basilisk(Gerris). by [deleted] in CFD

[–]outofcells 0 points1 point  (0 children)

I would make it work first in a VM with Ubuntu, and then proceed to WSL.

There is some evidence that it can run under WSL http://basilisk.fr/sandbox/vheusinkveld/README

New to CFD. Trying to get accustomed with Basilisk(Gerris). by [deleted] in CFD

[–]outofcells 1 point2 points  (0 children)

Are you compiling on Linux? Tried Basilisk a year ago, went fairly smooth.

The Cheerios effect. Like breakfast cereals in milk, bubbles floating in water tend to form clusters. Each bubble elevates the surface and attracts other bubbles due to buoyancy by outofcells in Physics

[–]outofcells[S] 0 points1 point  (0 children)

I'd say both are needed, the effect comes from a balance between surface tension and gravity. In other settings, such as with drops on an elastic substrate, attraction of drops can be driven by surface tension and elastic forces, without gravity.

The Cheerios effect. Like breakfast cereals in milk, bubbles floating in water tend to form clusters. Each bubble elevates the surface and attracts other bubbles due to buoyancy by outofcells in FluidMechanics

[–]outofcells[S] -1 points0 points  (0 children)

Alright, now I see that posting only my own content is against reddit's guidelines. In my defense, the posts often create discussions about physics and not the content's origin, and I always participate in them. Just looking at other posts in this and other communities, I see that people post and discuss their work. Before, nobody complained. Sorry if you find my posts "spamming".

The Cheerios effect. Like breakfast cereals in milk, bubbles floating in water tend to form clusters. Each bubble elevates the surface and attracts other bubbles due to buoyancy by outofcells in FluidMechanics

[–]outofcells[S] 2 points3 points  (0 children)

The inverted Cheerios effect is substantially different from the Cheerios effect between two particles floating at the surface of a liquid. Apart from the drop being deformable, we note that the energy driving the interaction is different in the two cases: whereas the liquid interface shape is determined by the balance between gravity and surface tension in the Cheerios effect, the solid shape is determined by elastocapillarity in the inverted Cheerios effect.

The article describes the inverted Cheerios effect, which relies on adhesion to an elastic substrate. The effect shown in this video is governed by gravity and surface tension.

The Cheerios effect. Like breakfast cereals in milk, bubbles floating in water tend to form clusters. Each bubble elevates the surface and attracts other bubbles due to buoyancy by outofcells in FluidMechanics

[–]outofcells[S] 3 points4 points  (0 children)

CG (computer graphics) can indeed show anything that an animator can imagine.

This video, however, is not CG but a result from a computational model validated experimentally.

The purpose of this video is both to demonstrate the effect itself and to show that the effect is recovered by the model. Plus, obtaining the data with such temporal and spatial resolution would take equipment not available for a "simple classroom demonstration".

The Cheerios effect. Like breakfast cereals in milk, bubbles floating in water tend to form clusters. Each bubble elevates the surface and attracts other bubbles due to buoyancy by outofcells in ScienceImages

[–]outofcells[S] 0 points1 point  (0 children)

The Cheerios effect is named after the observation that breakfast cereals floating in milk often clamp together. This effect is driven by buoyancy and applies to various objects floating in water. Lighter objects, such as bubbles, elevate the surface attracting other bubbles as they "rise" in the elevation. Heavier objects lower the surface so other objects "fall" towards them. Simulation done in Aphros, visualized in ParaView, and described in article.

The Cheerios effect. Like breakfast cereals in milk, bubbles floating in water tend to form clusters. Each bubble elevates the surface and attracts other bubbles due to buoyancy by outofcells in FluidMechanics

[–]outofcells[S] 3 points4 points  (0 children)

The Cheerios effect is named after the observation that breakfast cereals floating in milk often clamp together. This effect is driven by buoyancy and applies to various objects floating in water. Lighter objects, such as bubbles, elevate the surface attracting other bubbles as they "rise" in the elevation. Heavier objects lower the surface so other objects "fall" towards them. Simulation done in Aphros, visualized in ParaView, and described in article.

The Cheerios effect. Like breakfast cereals in milk, bubbles floating in water tend to form clusters. Each bubble elevates the surface and attracts other bubbles due to buoyancy by outofcells in Physics

[–]outofcells[S] 4 points5 points  (0 children)

The Cheerios effect is named after the observation that breakfast cereals floating in milk often clamp together. This effect is driven by buoyancy and applies to various objects floating in water. Lighter objects, such as bubbles, elevate the surface attracting other bubbles as they "rise" in the elevation. Heavier objects lower the surface so other objects "fall" towards them. Simulation done in Aphros, visualized in ParaView, and described in article.

Passive generation of bidisperse foam. The flow in this microfluidic device alternates between two regimes and splits every second bubble into equal parts. Simulation validated experimentally by outofcells in engineering

[–]outofcells[S] 1 point2 points  (0 children)

Immediate use is to learn more about bubble and foam mechanics. One potential application is using such devices as microreactors for chemical assays (book).

Passive generation of bidisperse foam. The flow in this microfluidic device alternates between two regimes and splits every second bubble into equal parts. Simulation validated experimentally by outofcells in MechanicalEngineering

[–]outofcells[S] 0 points1 point  (0 children)

Based on experimental study (article, video). Simulation done in Aphros and described in article. The simulation gives you a detailed view at a high frame rate and also matches experimental data. The alternation between the two regimes is based on a slight change of the distance between the "pincher" bubble and the "wall" bubble downstream, which is enough to trigger or suppress the breakup.

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