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Choosing l in external aero simulation & nu used in motorbike tutorial

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Old   November 28, 2017, 12:39
Default Choosing l in external aero simulation & nu used in motorbike tutorial
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Ed O'Malley
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Hi - new to OpenFoam. I'm working on an external aerodynamic simulation of a bike part - about 200mm in length, 70mm in width. I'm using the motorbike demo as a base to start from. Overall force results in the simulation seem low (0.1 to 0.2N at 10m/s air velocity - force is reported in N, right?), so I was going over some of the boundary conditions and I came up with a few questions -

The manual clearly describes how to calculate the turbulence length scale in pipe flow problems - but how is it done in external aerodynamic cases?

The motorbike and the simple car tutorials both use 1e-5 as the kinematic viscosity of air, but at 20C it is actually 1.5e-5 m^2/s. Is there a reason to choose the lower viscosity if I am simulated a full-scale model?

Thanks!
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external aerodynamics, kinematic viscosity, turbulent length scale


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