Flow in Arterial Bifurcations
Video of flow through a rectangular "T" shaped conduit, reminiscent of an arterial bifurcation. While obviously unlike typical arterial branchpoints, this model affords an opportunity to study some of the potentially complicated flow patterns that could occur. The right angle side branch is a geometric extreme that I once selected to help study whether local geometry could affect flow distribution. The uninitiated will think of the bifurcation of dividing the flow into 2 unconnected streams. The first video indicates that this is not the case.
Next is a High-Def view of the junction showing a fascinating aspect of this flow. A fluid surface that has already entered the straight branch, at the initial frame of the video, actually flows upstream along the conduit walls and eventually exits via the side branch.
While this result depends on circumstances, it's been verified to occur experimentally also.
2 Dimensional Examples
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3 Dimensional Aspects of Bifurcation Flow
Here's the video from the top of the page, recapitulated for the gist. Flows in the 2 branches remain connected.
The next is a displacement animation at Reynolds number 1000 with 75% of the flow into the side branch. The video depicts how flow that has already entered the straight branch flows upstream along the walls into a recirculation region and eventually exits the side branch. The rectangular cross-sectional geometry is a better test bed for the computations.
Next is a displacement animation viewed from the vicinity of the side branch. Flow enters from the left and the straight branch is off to the right. Again, a fluid surface in the straight branch has been labeled and the animation shows how it ends up coming towards you into the side branch. This is a high-def (HD) mp4 file and is larger that straight mpeg; it will run slow and jerky if your stream rate isn't fast enough.
Next is of a displacement animation of flow starting at the side branch. Reynolds number 1000 with 75% of the flow going into the side branch. k-epsilon turbulence model