I ran into the problem of correctly setting the values in the converter.
My geometry is a cube with impenetrable thin lintels inside it throughout its volume, like a porous medium. When i need a great resolution. The size of model is 3x3x3m, but i use stlReader where thrid parameter is equals 0.001. The cross-sectional area of lintels is average equals 0.2m (in model, when 0.0002m in simulation).
Then i set converter like this:
UnitConverter<T, DESCRIPTOR> const converter(
(T) 0.0001, // physDeltaX: spacing between two lattice cells in __m__
(T) 0.000002, // physDeltaT: time step in __s__
(T) 0.0035, // charPhysLength: reference length of simulation geometry
(T) 0.5, // charPhysVelocity: maximal/highest expected velocity during simulation in __m / s__
(T) 0.003/1055., // physViscosity: physical kinematic viscosity in __m^2 / s__
(T) 1055 // physDensity: physical density in __kg / m^3__
But during simulation i catch an error:
[LatticeStatistics] step=1200; t=0.3; uMax=0.73463; avEnergy=nan; avRho=nan
"./tmp/imageData/data/heatMapEuklidNormphysVelocity.p", line 21: warning: matrix contains missing or undefined values
What parameters should I set for the simulation to complete successfully? And what is right way to set the converter’s parameters?
I can only recommend to have a look in the text book of Krüger et al. https://www.springer.com/de/book/9783319446479. Chapter 7 is about dimensionalization of the Lattice Boltzmann Equation and on how to choose stable discretization parameters.