In this section we illustrate a simple macroscopic model to analyze a wind turbine. The schematic diagram is shown in Fig. 2.14. Fluid approaches the wind turbine at a velocity of v1 and pressure of pā. It leaves at a velocity of v2 as shown in the figure. We assume frictionless flow and hence the fluid downstream is at the same pressure pā as that at the inlet. The rate of working and the efficiency are to be calculated by doing a macroscopic analysis.