Servomechanism

The servomechanism does not influence turbine losses, but turbine performance as a function of servo-stroke is normally registered for turbines in operation and will give important information for modelling an existing turbine.
"Servomechanism" handles four types of mechanisms.

A fixed linear servomotor with cross-head connected to a rotating ring.
A tilting linear servomotor connected to a rotating ring.
Individual linear servomotors and a
servomotor connected to a ring with linear movement.

The servomechanism is exposed to  great forces depending on guidevane/turbine design and mode of operation.
Deformation due to these forces is not calculated, but a pre-stress related to stroke is taken into consideration. This will result in a constant stroke-displacement instead of a variable depending on forces. Guidevanes will stay closed for stroke less than the set pre-stress.

The default servomechanism displayed the first time window is opened has a tilting servomotor.

By the aid of a slider operation of servomechanism can be "tested".

Nozzle

Losses are friction losses depending on Reynolds number and surface roughness.
For small strokes needle loss will be high due to the thin layer of water with high velocity covering a relatively great part of the needle.