Fluid Dynamics, Rocket Jets and Leafy Capitals

Dr. Steven B Halls | December 2025

This material was originally posted to Facebook on 2025-12-09 - view original post.

Fluid dynamics. Image A is computer simulation of rocket jets as the thrust expands. https://www.facebook.com/share/p/17u9KCAdz7/

A computer simulation of rocket jets expanding resembles columns with leafy capitals, where a column is a flux tube with upward flow whose end does not abut the barrier above the capital, like a gushing fire hose pushed against a brick wall. Flux tubes spill contents that expand, curl, and sometimes reform small tubes, and the green man shows head-torus outflows going laterally from the mouth.

Image B and C are about columns that have a leafy capital. The column is a flux tube with upward flow, and I was surprised that the end of the column (near letters B and C) was not abutting the barrier above the capital. But an analogy came to mind that pushing a gushing fire hose against a brick wall would look like this too.

Image A reminded me of B and C (and many others). Flux tubes spilling their contents out, which expands and curls up, and sometimes small flux tubes reform in that complexity, that's what is shown on image F and I.

Green man on image G and H is showing the head-torus symbol having outflows going laterally from the mouth. Image D has lateral outflows that go down as expanding wavy tassles. Image E has a spiral expanding flux tube spilling out the analogy of fruit of various sizes. I was confused about flow direction of green man vegetation, but lately it seems clear. The sides of a mouth can also do inflows, but not in these examples. Many people were taught other stories about the green man, and capitals. Teaching about energy, versus teaching many different stories,

Occam's razor and Hanlon's razor comes to mind.

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