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Multispecies approach implemented in the code is based on the paper "Multi-species Lattice Boltzmann Model and Practical Examples. Short Course material Pietro Asinari PhD."

Equlibrium distribution function for multispecies is given in the paper as

where, for and , is molecular weight for species .

is given as

Relaxation time is given as

A semi-implicit Lattice Boltzmann equation is given as,

Variable transformation presented in above paper involves three steps

In back tranformation, to compute feq we need and can be computed directly from g

where as the computed by solving the linear system of equation given below

where, is,

use for optimized routine

```
!West
u_n(1) = - uxstar(s)
!south
u_n(2) = - uystar(s)
!bottom
u_n(3) = - uzstar(s)
!east
u_n(4) = uxstar(s)
!north
u_n(5) = uystar(s)
!top
u_n(6) = uzstar(s)
!bottom south
u_n(7)
!top south
u_n(7)
!bottom north
u_n(7)
!top north
u_n(7)
!bottom west
u_n(7)
!bo
u_n(7)
u_n(7)
u_n(7)
u_n(7)
```

Navigate: ← Features | Multispecies test case tutorial