Struct PyLbmSimulation 

pub struct PyLbmSimulation { /* private fields */ }

A 2-D D2Q9 Lattice-Boltzmann fluid simulation.

Supports:

• BGK collision operator (single relaxation time)
• Periodic streaming
• No-slip bounce-back walls via boundary map
• Velocity and density field extraction
• Lid-driven velocity boundary on top row

Implementations

impl PyLbmSimulation

pub fn new(config: &PyLbmConfig) -> Self

Create a new LBM simulation from configuration.

All cells are initialised to equilibrium at the configured density and velocity.

pub fn width(&self) -> usize

Grid width.

pub fn height(&self) -> usize

Grid height.

pub fn step_count(&self) -> u64

Number of completed steps.

pub fn set_boundary(&mut self, x: usize, y: usize, btype: LbmBoundary)

Set the boundary type of cell (x, y).

pub fn get_boundary(&self, x: usize, y: usize) -> Option<LbmBoundary>

Get the boundary type of cell (x, y).

pub fn add_top_wall(&mut self)

Mark all cells along the top row as NoSlipWall.

pub fn add_bottom_wall(&mut self)

Mark all cells along the bottom row as NoSlipWall.

pub fn add_enclosing_walls(&mut self)

Mark all four enclosing walls as NoSlipWall (cavity setup).

pub fn set_lid_velocity(&mut self, vel: Option<[f64; 2]>)

Set a lid velocity applied to the top row every step.

Pass None to disable.

pub fn velocity_at(&self, x: usize, y: usize) -> [f64; 2]

Get macroscopic velocity [ux, uy] at cell (x, y).

Returns [0, 0] for out-of-bounds or wall cells.

pub fn density_at(&self, x: usize, y: usize) -> f64

Get macroscopic density at cell (x, y). Returns 0 if out of bounds.

pub fn get_velocity_field(&self) -> Vec<f64>

Return the full velocity field as a flat Vecf64of[ux, uy]pairs, row-major (y outer, x inner). Length =width * height * 2`.

pub fn get_density_field(&self) -> Vec<f64>

Return the full density field as a flat Vecf64, row-major. Length = width * height`.

pub fn step(&mut self)

Advance the simulation by one LBM time step.

Steps:

1. Collision (BGK) + optional body-force correction.
2. Apply lid velocity (if set) as equilibrium on top row.
3. Streaming with periodic boundaries.
4. Bounce-back for NoSlipWall cells.

pub fn run(&mut self, steps: u64)

Run n steps.

impl PyLbmSimulation

pub fn mean_density(&self) -> f64

Mean macroscopic density over all non-wall cells.

pub fn max_speed(&self) -> f64

Maximum speed (magnitude of velocity) over all non-wall cells.

pub fn vorticity_field(&self) -> Vec<f64>

Vorticity field (z-component of curl) as a flat Vecf64.

Uses central differences. Length = width * height.

pub fn enstrophy(&self) -> f64

Enstrophy (0.5 ∫ ω² dA) — scalar measure of total vorticity.

pub fn reynolds_number(&self, omega: f64) -> f64

Reynolds number estimate: Re = L * U / ν (characteristic length = height/2).

pub fn speed_field(&self) -> Vec<f64>

Return the velocity magnitude field as a flat Vecf64.

pub fn reset_to_equilibrium(&mut self, rho: f64, ux: f64, uy: f64)

Reset all cells to equilibrium at given density and velocity.

pub fn add_circular_obstacle(&mut self, cx: usize, cy: usize, r: usize)

Set a circular obstacle (no-slip) at (cx, cy) with integer radius r.

pub fn fluid_cell_count(&self) -> usize

Count of fluid (non-wall) cells.

pub fn wall_cell_count(&self) -> usize

Count of wall cells.

impl PyLbmSimulation

pub fn collect_stats(&self) -> LbmStats

Collect per-step statistics.

Trait Implementations

impl Clone for PyLbmSimulation

fn clone(&self) -> PyLbmSimulation

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for PyLbmSimulation

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.