After the design point has been calculated, both steady state and transient off-design simulation calculations can be performed. Off-design operating conditions can be specified in many ways such as:
•Changing Flight conditions
•Fuel Flow or control-system power setting
•Compressor bleed variation
•Turbine power or torque variation, using the Power Turbine Load control
Off-design conditions may also be specified in the component data windows (usually, the basic off-design parameters are located in the General tab sheet).
The basic model layout and the design point should not be changed (i.e. design point data, changes which affect the number of states or component interconnections, numbers of bleed- or cooling flows etc.). In the latter case, GSP will generate an error message automatically or reset the model so as to require a new design point calculation first.
Changing component deterioration and variable geometry effects may also be calculated as off-design calculations.