Thermal NS

Full 3-D Incompressible Navier–Stokes · thermal on terrain

Date & Time

Simulation date

Target date for sun position and weather data.

UTC offset (h)

Interval (min)

Start time (local)

Sun elev at start (°)

End time (local)

Sun elev at end (°)

Edit start/end times; sun elevation at those times is shown for reference.

Terrain

Sim zoom

Mesh zoom

Zoom 12 ≈ 30 m/px (sim), zoom 14 ≈ 7 m/px (mesh). NS grid capped at 80×80.

Heating

ERA5 auto-calibrate max_heat

Fetches ERA5 data to derive max_heat from observations.

Weather mode

Typical (5-year ERA5 average) Exact (past date only)

max_heat (K) — manual fallback

Peak ground-air temperature anomaly under full insolation.

ERA5 window (days)

Diffuse fraction

Env. lapse rate (K/km)

Environmental lapse rate. DALR=9.76 K/km. ELR < DALR = stable.

Thermal Inertia

τ hours (reference grassland)

Time constant for ground heating. ~1 h bare rock, ~1.5 h mixed, ~3 h forest.

Atmospheric Physics

DALR (K/km)

Turbulent Prandtl Prₜ

DALR: dry adiabatic rate (fixed physics, 9.76 K/km). Prₜ: ratio of momentum to heat diffusivity — lower = more heat diffusion relative to momentum.

Diffusion CFL factor

Clamps νₜ for diffusion stability: νₜ ≤ factor·Δ²/dt. Lower = more conservative.

Solar Radiation Model

T_atm base

T_atm exponent

Kasten-Czeplak transmittance: T_atm = base^(AM^exp). Lower base = hazier sky; higher base = clearer.

Slope smooth σ (cells)

Land cover smooth σ (cells)

Gaussian smoothing applied to slope incidence and land cover thermal factor. Higher σ = smoother heating patterns.

NS Solver Parameters

Horizontal NX

Horizontal NY

Vertical layers NZ

Domain height (m)

NS time step (s)

Smagorinsky Cs

SOR omega

Pressure max iter

SOR mean-removal freq

Red-Black SOR pressure solver. Mean-removal frequency: remove mean pressure every N iterations to handle Neumann null space.

Visualization

View height (m AGL)

Steps per frame

Height for plan-view slice. Steps between UI updates (higher = faster sim).