DarcyWeisbachféle

The Darcy-Weisbach equation is a fundamental empirical equation used in fluid dynamics to determine the head loss due to friction in a pipe. It relates the pressure drop or head loss of a fluid flowing through a pipe to the average velocity of the fluid, the pipe's diameter, the pipe's length, the fluid's density, and the fluid's dynamic viscosity. The equation is given by h_f = f_D * (L/D) * (v^2 / 2g), where h_f is the head loss, f_D is the Darcy friction factor, L is the length of the pipe, D is the hydraulic diameter of the pipe, v is the average velocity of the fluid, and g is the acceleration due to gravity.

The Darcy friction factor, f_D, is a dimensionless quantity that accounts for the resistance to flow caused by the pipe's surface roughness and the flow regime (laminar or turbulent). For laminar flow, the friction factor can be calculated analytically. For turbulent flow, f_D depends on the Reynolds number and the relative roughness of the pipe. This dependence is often determined using empirical correlations, such as the Colebrook equation or Moody charts.

The Darcy-Weisbach equation is widely used in various engineering applications, including the design of water supply systems, oil and gas pipelines, and HVAC systems. It is considered the most accurate method for calculating frictional head losses in pipes, particularly for turbulent flow conditions. Its validity relies on experimental data and empirical relationships, making it a cornerstone of practical fluid mechanics.