Lattice Boltzmann Fluid Simulation

D2Q9 lattice Boltzmann method: fluid distributions f_i evolve via streaming and BGK collision f_i' = f_i − (f_i − f_i^eq)/τ. Vortex shedding emerges naturally from simple local rules.

Flow Field (click to add obstacle)

LBM Parameters

f_i' = f_i − (f_i−f_i^eq)/τ
f_i^eq = ρw_i[1 + u·c_i/cs² + ...]
ν = cs²(τ−1/2)Δt
Re = UL/ν

Flow Diagnostics

Reynolds Re ≈---
Kinematic ν---
Max |u|---
Step0
D2Q9 velocities:
c_0=(0,0), c_1=(1,0), c_2=(0,1)
c_3=(-1,0), c_4=(0,-1), ...
Weights: w_0=4/9, w_1-4=1/9
w_5-8=1/36 (diagonal)