2. Reminders about similarity

Two turbomachines are said to be of the same type when they are geometrically similar, i.e. all lengths are in the same ratio of geometric similarity.

High-Reynolds-number load flow through the turbine obeys the same laws of similarity as perfect-fluid flow, except for losses.

The Combe-Rateau similarity relates flows to falls and two geometrically similar turbines – index p for the prototype, index m for the model – will verify: