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Experimental evidence of near-wall reverse flow events in a zero pressure gradient turbulent boundary layer
- Source :
- Experimental Thermal and Fluid Science, Experimental Thermal and Fluid Science, Elsevier, 2017, ⟨10.1016/j.expthermflusci.2017.10.033⟩
- Publication Year :
- 2017
-
Abstract
- This study reports on experimentally observed rare near-wall reverse flow events in a fully developed turbulent flat plate boundary layer at zero pressure gradient with Reynolds numbers between Re θ ≈ 2500 and Re θ ≈ 8000 ( Re τ ≈ 800 – 2400 ). The reverse flow events are captured using high magnification particle image velocimetry sequences with record lengths varying from 50 000 to 126 000 samples. Time resolved particle image sequences allow singular reverse flow events to be followed over several time steps whereas long records of nearly statistically independent samples provide a variety of single snapshots at a higher spatial resolution. The probability of occurrence lies in the order of 0.012–0.018% which matches predictions from direct numerical simulations (DNS). The typical size of the reverse flow bubble is about 30 wall units in length and 5 wall units in height which agrees well with similar observations made in existing DNS data.
- Subjects :
- General Chemical Engineering
Bubble
Aerospace Engineering
01 natural sciences
010305 fluids & plasmas
Physics::Fluid Dynamics
010309 optics
symbols.namesake
[SPI]Engineering Sciences [physics]
0103 physical sciences
Triebwerksmesstechnik
Experimentelle Verfahren, GO
Shear stress
Data_FILES
Pressure gradient
ComputingMilieux_MISCELLANEOUS
Fluid Flow and Transfer Processes
Physics
[PHYS]Physics [physics]
Turbulence
Mechanical Engineering
[SPI.FLUID]Engineering Sciences [physics]/Reactive fluid environment
Reynolds number
Mechanics
Particle image velocimetry Turbulence statistics Boundary layer Flow reversal Wall shear stress
Boundary layer
Nuclear Energy and Engineering
Particle image velocimetry
Flow (mathematics)
symbols
Subjects
Details
- Language :
- English
- ISSN :
- 08941777
- Database :
- OpenAIRE
- Journal :
- Experimental Thermal and Fluid Science, Experimental Thermal and Fluid Science, Elsevier, 2017, ⟨10.1016/j.expthermflusci.2017.10.033⟩
- Accession number :
- edsair.doi.dedup.....8d8a42914dd36d61a9aaf7b105eb3063