4. Study of boundary conditions

In the previous paragraphs, we focused on determining what was happening inside a tube. Assuming that this tube was discretized into n meshes, the equations were solved between meshes 2 and n – 1, assuming that the conditions at meshes 1 and n, i.e. the boundary conditions, were known.

In this section, we'll explain how these boundary conditions can be calculated, i.e. how to determine the flow conditions at the tube inlets and outlets. These conditions depend, in general, on the conditions outside the tube and also on the conditions inside the tube.

Intake and exhaust system tubes communicate with the atmosphere, or are connected to capacities (volumes, silencers, catalytic converters) and components (such as cylinders, turbochargers or singular pressure drops). These tubes are also connected to each other to form the various branches of...