fluid_

Incompressible flow on a Cartesian grid with pressure projection. Add inlets, outlets, and solid bodies to watch the field deform.

Fluid

Reynolds (speed·width/ν)—

Simulation

viscosity ν 0.00020 pressure iterations 40 time step Δt 0.015 grid resolution buoyancy (heat rises) 4.0 flow display

show grid

show velocity vectors

airflow particles

Objects

Build a room: drag walls (snap horizontal/vertical), add furniture with rectangle/circle, then drag a window / door across a wall to cut an opening. Speed 0 = open outlet (pressure 0); give it a speed + direction to blow wind in. Inlets act as fans/vents. Windows may also sit on the outer edge of the domain.

Colors flow palette

reverse

solids

particles

Click a swatch to edit that colour stop (left = low value, right = high). Signed views (pressure, vorticity, temperature) use the middle as zero.

Layout

load preset room

Diagnostics

grid—

maximum speed0.00

divergence rms0.0000

objects0

drag on selected solid—

lift on selected solid—

Equations

∂u/∂t + (u·∇)u = −(1/ρ)∇p + ν∇²u
∇·u = 0
∇²p = (ρ/Δt) ∇·u*
uⁿ⁺¹ = u* − (Δt/ρ)∇p

← a98k · made by hand, no frameworks

mode: select

drag to move · green ● rotate · yellow ■ resize · blue ◆ flow direction/speed · Shift snaps · Esc = select

choose an airfoil

Placed in the middle of the canvas as a solid. Use the green handle to set the angle of attack, the yellow square to resize. Esc closes.