Changing the aorta3d to air flow

[talco]

Dear OpenLB users,
I’m trying to change the aorta3d example from water flow to air flow
I have changed the following parameters:
FluidDensity = 1 (Was 1055 before for water)
Kinematicviscosity = 0.00001488 (Was 0.003/1055 before for water)
maximal expected velocity = 400 (randomly a larg number)

But at the first time step the velocity exploeds

I have also tryed to change the lattice.defineDynamics<BulkDynamics> to lattice.defineDynamics<BGKdynamics>
But the velocity still exploeds at the first time step

Any good idea ?

[Adrian]

Changing the bulk dynamics from a LES to a non LES model is very unlikely to help here as your new parameters will lead to an even higher Reynolds number.

The issue is probably that the Aorta case (which should be parameterized for blood, not for water – of course in the end all that matters are that the non-dimensional characteristic values, e.g. the Reynolds number, match what you want to simulate) there is a sinusoidial inflow applied up to your characteristic max velocity of 400 m/s. Considering that all of this relates to a characteristic length of (if you did not change it) only 0.02246m it is probably clear that you will get stability issues.

[Author]

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