While researching turbine engines I came across a statement
The mass of airflow naturally does not change in the transfer of energy to the rotor system, but the velocity of mass flow being slowed axially is said to account for the energy of flow as the energy of shaft power is increased. In other words, tangential velocity is essentially a loss of kinetic energy to the engine.
Why and how does this the loss occur, and how can this loss be reduced?
I'm not trying to get an in-depth mathematical aspect on that topic as I'm still a beginner with the study of gas turbines, a simpler theoretical non-math explanation would very much be appreciated, thanks!