(a) Whole system which is usually too expensive for simulation, as what I know, some company does simplified system components such as resistance blocks in system loop. So doing simulation of turbine, user have options to do The turbine working environment decides the working point on the turbine curve. The bigger of the pressure jump, the less of the flow rate. For a designed turbine and under a given blade rotating RPM, there is a turbine curve (or called fan curve) to determine the relation of the (a) pressure jump and (b) flow rate (identical to wind speed). To decide the relation among turbine required torque, RPM and wind speed, some other factors has to be counted in such as environment of the turbine, and fluid property(guess you are talking about air here). First let me explain and clarify general concept on turbine simulation.
