Druckkraft

Druckkraft, in physics and engineering, denotes the force exerted by a fluid’s pressure on a surface. It is a normal force, acting perpendicular to the surface, and its magnitude depends on the pressure distribution over the surface. For a flat surface of area A subjected to a uniform pressure p, the Druckkraft is F = p · A, directed into the surface.

In general, the Druckkraft on a curved or nonuniform surface is obtained by integrating the local pressure over the surface. The resultant force is a vector given by F = ∮ p(s) n(s) dA, where n(s) is the outward unit normal at each surface element dA. The direction of the Druckkraft is normal to the local surface element, and the total force is the vector sum of all elemental forces.

In hydrostatics and fluid mechanics, pressure typically varies with depth. For a fluid with density ρ subjected to gravitational acceleration g, the pressure at depth h is p = p0 + ρ g h, leading to depth-dependent Druckkräfte on submerged walls, floors, or hulls. The overall force can be found by integrating the pressure distribution over the affected surface.

Units and relation to stress: Druckkraft is measured in newtons, arising from pressure measured in pascals (1 Pa = 1 N/m²). For fluids, pressure is isotropic and contributes to the normal (compressive) component of the stress; in solid mechanics, the Druckkraft corresponds to the normal traction on a surface as described by the Cauchy stress tensor. Applications include hydraulics, pneumatics, ship hull design, dam engineering, and biomedical contexts where fluid pressure acts on surfaces.