Run a D2Q9 LBM wake experiment with a cylinder you can position while paused, then keep fixed during target runs for computed diagnostics.
flowPrototype
D2Q9 LBM / CYLINDER WAKE
Run a lattice Boltzmann solver with a cylinder you can position while paused, then keep fixed during target runs.
Finite: OK
NO PARTICLES / NO STREAMLINES
OMEGA FROM VELOCITY FIELD
SYSTEM NOTE
A cylinder wake candidate from the solver, not from a drawing trick.
The cylinder position can be adjusted while paused. During a target run it stays fixed so the wake metrics from D2Q9 LBM / BGK steps, sponge outlet, wall boundaries, and computed vorticity stay meaningful.
OBSERVATION POINTS
Develop the flow, then read the alternation metrics.
Fast + Quick is the default path for a first browser run.
Vorticity view maps computed omega = dv/dx - du/dy; it does not place vortices by hand.
Cancel keeps partial progress visible and leaves the controls usable again.
SYSTEM NOTE
D2Q9 LBM stores f0..f8 distributions and uses BGK relaxation toward equilibrium. nu = (tau - 0.5) / 3, Re = U D / nu, and vorticity is omega = dv/dx - du/dy. The cylinder uses bounce-back cells; its position can be adjusted while paused, then kept fixed during target runs with a left inlet, sponge outlet, and no-slip wall rows. Sign alternation count, first alternation step, oscillation amplitude, density drift, and finite status are diagnostic values from the computed field.
OBSERVATION GUIDE
Touchpoints for Observation
Observe a cylinder wake candidate developing from a D2Q9 LBM / BGK solver, then compare speed, vorticity, density drift, and sign alternation metrics.
Use Fast + Preview 2500 first to watch the wake begin to grow, adjust the cylinder only while paused, switch Speed, Vorticity, and Density views, and cancel longer target runs whenever the browser wait is too long.
Vorticity view is computed omega, not hand-placed vortices.
Target runs keep the cylinder position fixed for that run so wake diagnostics remain meaningful; dragging during a target asks you to Cancel first.
Compact and Fast are short first-look presets; Balanced is the standard verification preset, and Wide is a longer advanced check.
Density is a pressure-like proxy in the lattice, not a strict pressure field.
This is a lightweight browser numerical experiment for observing a Karman vortex street candidate. It is not a formal CFD solver, engineering design tool, wind-tunnel measurement, or proof that every condition produces a vortex street.
Runs inside the browser with no upload and no registration.
OBSERVATION POLICY
This lab runs in your browser. No image, pointer trace, or input is uploaded by this prototype.