Abstract
An experimental investigation of a starting vortex flow around a backward-facing step was conducted in a water channel. The properties and structures of the flow were investigated by qualitative flow visualization using the hydrogen bubble method and by quantitative velocity and vorticity measurements using White-light Bubble Image Velocimetry (WBIV) — a newly developed PIV method. Some invariant properties and 4-stage structures of starting vortex flow were observed.
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Abbreviations
- a :
-
flow acceleration during starting stage
- h :
-
height of backward-facing step
- d v :
-
dimensionless vortex size
- t :
-
time
- t :
-
dimensionless time
- U∞ :
-
free uniform velocity
- u, v :
-
streamwise and spanwise velocity components respectively
- Re :
-
Reynolds number based on a and h
- x, y :
-
streamwise and spanwise coordinates respectively in flow field
- x c , y c :
-
dimensionless vortex center position
- ω :
-
vorticity
- ovω :
-
dimensionless vorticity
- ω max :
-
maximum vorticity
- ovω max :
-
dimensionless maximum vorticity
- Γ :
-
circulation
- \(\bar \Gamma \) :
-
dimensionless circulation
- ν :
-
kinematic viscosity
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This work was supported by the CNSF Grant 1939 100-1-3
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Shen, G.X., Ma, G.Y. The investigation on the properties and structures of starting vortex flow past a backward-facing step by WBIV technique. Experiments in Fluids 21, 57–65 (1996). https://doi.org/10.1007/BF00204636
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DOI: https://doi.org/10.1007/BF00204636