## Fundamentals of mathematical river flow modelling - 2D flow calculation

### BASIC HYDRODYNAMIC EQUATIONS

In the following chapters, the basic hydrodynamic equations for two-dimensional depth-averaged flow calculation will be derived step by step. We will begin with the two-dimensional Navier-Stokes equations for incompressible fluids, commence with Reynolds equations (time-averaged), and end with the depth-averaged shallow water equations.