WindSim

WindSim is a browser-native aerodynamics project with two distinct surfaces:

• sandbox.html: the working reduced-order 3D wind sandbox
• cfd.html: the Phase A CFD laboratory shell for the future WebGPU solver stack

The launcher at index.html routes between them.

Source Of Truth

docs/CFD_MASTER_BLUEPRINT.md → CFD implementation phases docs/WINDSIM_ENGINEERING_PLAN.md → full system architecture and requirements

That blueprint is the active plan for the CFD side of the repo. The core rule is simple: the UI must not imply solved physics that the code does not actually compute.

Current State

Sandbox

The sandbox is the mature part of the project. It currently provides:

• reduced-order rigid-body aerodynamics with drag, lift, Magnus force, rotation, contact, and telemetry
• experiment workflows such as mounted mode, playback, sweeps, saved comparisons, and flow-probe slices
• a modular split across js/windsim-app.js, js/windsim-physics.js, js/windsim-ui.js, js/windsim-scene.js, js/windsim-workflows.js, js/windsim-textures.js, and js/windsim-models.js
• multiple solver registrations through js/windsim-solvers.js

CFD Lab

The CFD surface is not a finished solver yet.

What is real today:

• WebGPU capability detection and hardware-tier routing
• a strict Phase A workflow shell for geometry, domain, boundary, and solver setup
• a Three.js viewport and domain visualization for the CFD surface
• a dedicated blueprint and project direction for the full solver stack

What is not real yet:

• a production LBM D3Q19 kernel running inside cfd.html
• validated drag, lift, pressure, or streamline outputs from the CFD surface
• full geometry import, voxelization, observability logging, and post-processing from the blueprint

Experimental Solver Work

js/windsim-cfd.js contains an experimental 2D grid-based solver path for the sandbox side. It is transitional work, not the final CFD lab backend, and it does not yet replace the full reduced-order pipeline with a true coupled 3D solver.

Repo Layout

• index.html Launcher that routes to the sandbox or the CFD lab.
• sandbox.html Working reduced-order simulator surface.
• cfd.html Phase A CFD shell.
• css/windsim-entry.css Entry and landing system styling for the sandbox experience.
• css/cfd-entry.css CFD lab styling.
• js/windsim-*.js Sandbox modules.
• js/cfd-engine.js CFD shell engine, hardware detection, viewport setup, and workflow gating.
• js/windsim-cfd.js Experimental sandbox-side grid solver work.
• docs/CFD_MASTER_BLUEPRINT.md Active CFD implementation blueprint.
• docs/CHANGELOG.md High-level change history.

Honesty Rules

• The sandbox can use reduced-order and heuristic models, but it must label them honestly.
• The CFD lab must not show fake solved outputs.
• If a feature is not wired to real computation yet, it should stay locked, blank, or explicitly marked as shell-only.