General principles of hydrodynamics
Hydrodynamic Transmissions

In hydrodynamic transmissions, the energy delivered by the diesel engine is modified in its characteristics and re-transmitted in mechanical form via hydraulic circuits. These operate according to the laws of fluid dynamics.

Due to the high flow rates and velocities in the circuits, and therefore the high energy concentration, the fluid regime is of the turbulent type.

For ease of understanding and simplification, we'll assume that the fluids we use are perfect (although mineral or synthetic oil is generally used), i.e. incompressible, with no viscosity (no pressure drop) and no thermal conductivity.