Hidrodinamike

Hidrodinamike, or hydrodynamics, is the branch of fluid mechanics that studies the motion of liquids and the forces acting on them. It seeks to understand how fluids respond to boundaries, pressure gradients and external forces, and how these motions can be predicted in natural and engineered systems. In many contexts hydrodynamics treats liquids as continuous media and applies conservation laws to derive governing equations.

The core of the subject is the Navier–Stokes equations for viscous fluids, together with the continuity equation for mass conservation. For ideal (inviscid) fluids, the Euler equations and Bernoulli’s principle provide simplified descriptions along streamlines. Fluids can be incompressible or compressible, Newtonian or non-Newtonian, and the flow can be laminar or turbulent, depending on factors such as viscosity, density and characteristic length and velocity scales.

Common problems include predicting the flow around objects (drag and lift), internal flows in pipes (Hagen–Poiseuille type solutions), and open-channel or free-surface flows. Boundary conditions, such as the no-slip condition at solid boundaries or the behavior at a free surface, are essential for solving practical problems.

Methods used in hidrodinamike range from analytical approaches (potential flow theory, complex analysis in two dimensions) to numerical techniques (computational fluid dynamics) and experimental methods (flow visualization, particle image velocimetry).

Applications span engineering (aerodynamics, naval architecture, hydraulics), environmental and geophysical flows (oceanography, groundwater movement), and biomedical contexts. The field has a long history, with foundational contributions from Euler and d’Alembert in fluid dynamics, and Navier–Stokes and Stokes in viscous flow theory. Dimensional analysis, yielding numbers such as the Reynolds number, aids in classifying regimes and scaling experiments.