LB animations

Lattice Boltzmann Method LBM: Algorithms
#1

Good morning everyone,
my name is Alessandro and I took the PhD degree studying fluid-structure interaction problems by coupling LB and finite element methods. I want to share with your community several results I achieved. I used a C++ code developed by myself:

https://www.youtube.com/user/alexderosis/videos?flow=grid&view=0

Alessandro

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#2

Good morning Alessandro,
thanks for sharing. Have you been able to simulate rotating machinery so far? That would be an interesting application!

#3

Hi Alessandro !!!

I’m a pgd student too, and i used the coupled method DEM and LBM in 2D. I used a C++ code developed by myself. I have more questions please.
I’d like to have your opinion on the best technique to use to set the parameters of LBM simulation.

First technique :

  • Fixed dimensionless relaxation time " tau " ( 0.5 < tau < 1.5)
  • Fixed lattice grid spacing " dx" (m) (depending on the resolution LBM)
  • Fixed kinematic fluid viscosity (in SI units: m2/s) “nu”
  • Comptute LB timestep " dt_LB " (s) dt_LB = dx * dx * ( tau - 0.5 ) / ( 3 * nu)
  • Compute lattice speed " C" (m/s) : C = dx / dt_LB

Second tehnique :

  • Fixed lattice speed " C" (m/s)
  • Fixed lattice grid spacing " dx" (m) ( depending on the resolution LBM)
  • Fixed kinematic fluid viscosity (in SI units : m2/s) “nu”
  • Comptute LB timestep " dt_LB " (m): dt_LB = dx / C
  • Compute dimensionless relaxation time " tau " ( 0.5 < tau < 1.5) : tau = (3 * nu) / (C * dx) + 0.5

Then I would like to vary the kinematic viscosity of the fluid, for different values ​​of the fluid velocity imposed (Von Neumann Boundary conditon at Inlet U_inlet # 0) . In outlet , i was Imposed dirichlet pressure boundary conditions (rho_out = 1.0).

and i want to know in details how do you compute the solid coverage ratio in 2D for immersed coupled boundary method. Can help to compute this coverage contribution from solid obstacles that intersect a lattice cells. I want to use a curved solid boundary treatment

https://www10.cs.fau.de/Publications/Theses/2005/Iglberger_MT.pdf

Thank you for your help

Best regards and be blessed