🏙️ Atmospheric Boundary Layer Wind Profile

Calculate atmospheric boundary layer wind velocity gradient using Log-Law and Power-Law, dynamic wind stagnation pressure on facades, and base overturning moments.

⚡ Fortran 90 Engine Double Precision (IEEE 754) ✓ ISO / ASME Validated

Cfd

📊 Solver Telemetry ● ACTIVE

👁️ Views 15

⚡ Solves 13

💾 Downloads 511 📦 Fortran Code 4.4 KB

📅 Released Jun 2026

⏱️ Latency < 1 ms

🏙️ Atmospheric Boundary Layer & Vertical Wind Velocity Gradient

Real-time visual simulation of ground roughness shear, logarithmic velocity profile & high-rise structural drag

📝 Configuration & Presets

🏙️ City Skyscraper (200m) 🌊 Offshore Wind Mast (140m) 🏭 Suburban Warehouse 📡 Rural Mast (100m)

💨 Reference Wind & Terrain

Reference Wind Speed U_ref [m/s]: Standard at 10m height (e.g. 25 m/s ≈ 90 km/h)

Terrain Roughness Length z₀ [m]: Sea: 0.002, Open: 0.03, Suburb: 0.30, City: 1.0–2.0

Power-Law Exponent α: Sea: 0.12, Open: 0.16, City: 0.33

Air Density ρ [kg/m³]:

🏢 Building / Structure Dimensions

Building Height H [m]:

Facade Width W [m]:

ABL Wind Engineering Formulations:
• Log-Law Profile: U(z) = (u*/κ) · ln(z / z₀) [m/s]
• Friction Velocity: u* = (κ · U_ref) / ln(z_ref / z₀)
• Dynamic Stagnation Pressure: q(z) = ½ ρ [U(z)]² [Pa]
• Turbulence Intensity: I_z(z) ≈ 1 / ln(z / z₀)

📊 Wind Engineering Results

📊 Output Summary
💾 Fortran Source

Building Top Wind Speed (U_top)

U(H) = 62.7 m/s (225.8 km/h)

Dynamic Pressure: 2,411 Pa (2.41 kPa)

H = 200 m

Friction Velocity (u*) 4.91 m/s Roughness z₀ = 1.200 m

Top Turbulence Intensity (I_z) 19.5 % At z = 200 m

Base Overturning Moment 1,798,751 kN·m 1798.75 MN·m

Total Facade Wind Shear 14,412 kN Integrated Drag Force

📈 Wind Velocity U(z) [m/s] vs Elevation Height z (m)

📉 Dynamic Wind Pressure q(z) [Pa] vs Elevation (m)

=================================================================
 THERMOFLUIDCALC — ATMOSPHERIC BOUNDARY LAYER REPORT
=================================================================
Case Title                 : High-Rise Skyscraper in Dense Urban City Center
Reference Wind Condition   : Uref = 26.00 m/s at zref = 10.0 m (93.6 km/h)
Terrain Parameters         : Roughness z0 = 1.2000 m, Power-law alpha = 0.330
Structure Dimensions       : Height H = 200.0 m, Width W = 40.0 m
-----------------------------------------------------------------
Friction Velocity (u*)     : 4.905 m/s
TOP WIND SPEED (Log-Law)   : 62.74 m/s (225.8 km/h)
TOP WIND SPEED (Power-Law) : 69.87 m/s (251.5 km/h)
Top Dynamic Wind Pressure  : 2,410.6 Pa (2.411 kPa)
Top Turbulence Intensity   : 19.5 %
Integrated Total Wind Shear: 14,411.7 kN
Base Overturning Moment    : 1,798,750.5 kN.m (1798.75 MN.m)
=================================================================

📘 Calculation Methodology & ASCE 7 / Eurocode 1 Standards

Atmospheric Logarithmic Law

Derived from Prandtl mixing length theory for neutral atmospheric boundary layer equilibrium over rough terrain:

                    U(z) = (u* / κ) · ln(z / z₀)
                

Dynamic Wind Pressure & Overturning

Dynamic wind stagnation pressure scales quadratically with height: $q(z) = \frac{1}{2} \rho [U(z)]^2$, creating substantial overturning moments on high-rise structures.

Key Engineering Assumptions

Neutral atmospheric thermal stability (no strong convective inversions).
Homogeneous fetch and uniform aerodynamic terrain roughness $z_0$.
von Kármán constant $\kappa = 0.40$.

ThermoFluidCalc Engineering Report