This example is a two-dimensional study of a fluid flow within a channel with a backwards-facing step.
The flow pattern will again be calculated using the incompressible Navier-Stokes equations for a Reynolds number of Rn = 250, which for this problem lies in the laminar range (the transitional range lies between 1200 < Rn < 6600).
The geometry consists basically of a box, representing the channel, with a step on the channel bottom.
- Backward-facing step
- Viscous, non-turbulent case
- Reynolds number of 200
The Reynolds number is defined here as: Re = 2νmax·Dρ / 3μ with the characteristic length of the problem, D being the height of the inlet channel.
The factor 2/3 derives from the assumption of a parabolic velocity profile in the inlet section with vmax being the maximum velocity value attained in this section.
The Reynolds number derives from the choice of the following parameters:
- D = 1.5 m
- νmax = 0.5 m/s
- r = 1000 kg/m3
- m = 2 kg/m.s
According to the previous equation we obtain
Re = 250
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