Implement 'mean-line' loss models for turbine performance evaluation.

[EliasAoubala]

** This is an extension of issue #2 **

In-order to allow for performance evaluation of designed turbine stages, it is common that mean-line loss models driven based on empirical data be implemented.

These typically consist of a series of performance penalties such as tip-loss, secondary flow losses, etc.

Although achieving accurate representative results it typically quite difficult, these models are commonly used in preliminary design to turbine stages.

Thus it is suggested that the following series of mean-line loss models be implemented for turbine design analysis:

• Craig and Cox
• Auginer
• Kacker and Okapuu