TRANSITION TO TURBULENCE
Pictorial Summary: Patterns in Fluid Flow Paradoxes - Variations on a Theme
This Summary reveals that, on pages 62-63 of this 1980 book, are words that predicted, precisely, the “new", highly organized transverse flows discovered on computerized transverse tomography images – SPIV (stereoscopic particle image velocimetry) in Faisst’s 2003 PhD Dissertation.
However, SPIV imaging as still used today suffers from rotational motion blur. Medical Imaging scientists know that tomography is not a freeze-frame, stop-action technique; unrecognized axial rotation of a turbulent cylinder’s turbulent flow column introduces motion blur of the fine flow detail predicted accurately theoretically in 1980.
Medical Imaging Insights Into The Enigma Of Transition To Turbulence
Recognizing co-existing simple harmonic (SH) sound waves and SH fluid shear waves in arteriographic standing waves inspired a literature SEARCH of SH waves and sound effects in transition to turbulence. A SH vibrating mass creates a signature flow pattern – a propulsive flow, flanked by two counter-rotating vortices. Nikuradse’s 1930 images display such flows in turbulence, arising from the boundary layers of the mid-walls of each side of tubes with geometric cross-sections; each side of Nikuradse’s tubes is a long narrow flat plate. SH laminar oscillations (laminar vibrations) develop during transition in boundary layer laminae along a flat plate. All boundary layer laminae flutter up and down in phase – despite many unique velocities, creating amplified SH sound beats, in phase with SH high and low hydraulic pressure waves in turbulent efflux jets from arteriogram needles as turbulence onset revealed that cylinder turbulence causes axial rotation of the water column.
Computerized transverse tomography of turbulent cylinder flow (SPIV images), 2003-2021, revealed the complex Nikuradse flow patterns, but axial rotation causes image blur, obscuring the Nikuradse fine flow detail. A literature review, and two medical imaging phenomena – periodic arterial waves and axial spinning of turbulent water jets from arteriogram needles, combine to explain “the oldest unsolved problem in physics,” – the cause of transition to turbulence.
This is the companion article elaborating on imagery in the Electronic Poster presented at the Canadian Association of Radiologists' 2021 Annual Scientific Meeting, Arteriographic Standing Waves, The Key to the Mystery of “The Oldest Unexplained Problem in Physics”,The Cause of Turbulent Flow.
Periodic sound beat aqueous standing waves along rigid and compliant boundaries
September 22, 2021
This is a new defining essay on the essence of transition to turbulence. It is a short illustrated essay on the cause of enigmatic turbulent spots, the immediate precursors of turbulent flow along boundaries. It is based on fundamental physics, and is presented in easy-to-understand terms and language. The answer to the riddle of transition to turbulence lies in understandable (but convoluted) fundamental physics.
T-S sound beats, boundary braking, vortices and turbulence
July 2, 2020 - Submitted to the International Journal of Aeroacoustics
Arising out of laminar flow, the simple harmonic (SH) T-S shear waves – a complex of boundary layer flutter (BLF) waves, wavy path (WP) waves and sub-T-S waves – may be "travelling" or stationary. T-S waves create SH transverse sound and periodic sound beats and vertical hydraulic pressure bands that freeze laminar slip, first focally, creating turbulent spots, and then generalized, creating noisy high-resistance turbulent flow. In water flow, alternating high and low transverse pressure bands, superimposed on periodically on similar compression / decompression bands of sound beats created by the BLF waves, result in SH standing waves. In late transition, amplified transverse sound waves, coursing perpendicularly through horizontally-flowing T-S wave laminae, cause random foci of laminar freezing (laminar interlocking), which are ripped out of T-S wave crests as random turbulent spots. Turbulence arises as generalized laminar freezing erupts, creating many random turbulent spots and noisy high resistance turbulent flow.
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