Winddruck

Winddruck, in meteorology and engineering known as wind pressure, describes the force per unit area exerted by moving air on a surface. It arises from the wind’s kinetic energy rather than the static atmospheric pressure and is a key component of wind loading on structures and objects.

The physical basis is the dynamic pressure q, given by q = 1/2 ρ v^2, where ρ is air density and v is wind speed. At sea level and standard conditions, ρ is about 1.2 kg/m^3, so the dynamic pressure increases with the square of wind speed. The actual pressure on a surface is p = Cp q, where Cp is the pressure coefficient that depends on wind direction relative to the surface, surface orientation, roughness, shape, and turbulence. Cp can be positive (pressure on windward faces) or negative (suction on leeward faces or rooftops).

Winddruck varies with height, terrain, and surrounding obstacles, leading to different loads at different points on a building or object. In civil engineering, wind loads are specified in design standards and codes to ensure safety and serviceability. Measurements of wind speed through anemometers, together with local Cp values, are used to estimate wind pressure on façades, roofs, and other surfaces. For example, at 40 m/s (about 144 km/h), with ρ ≈ 1.2 kg/m^3, the dynamic pressure is roughly 1 kPa; Cp values determine how this translates into actual surface pressures on windward and leeward sides.

Winddruck is thus a foundational concept for understanding how wind interacts with structures, vehicles, and other exposed surfaces, and it is central to modern design and safety standards.