rotor installed in a fixed orientation with the swept area perpendicular to thepredominatewind direction is called

The type of rotor you're referring to is typically called a "Horizontal Axis Wind Turbine" (HAWT). Here are the steps that explain why:

1. Wind turbines are generally classified into two types based on the orientation of their rotor - Horizontal Axis Wind Turbines (HAWTs) and Vertical Axis Wind Turbines (VAWTs).

2. HAWTs have their rotor shaft and generator installed at the top of a tower, and the rotor blades are oriented parallel to the ground. This means the swept area (the area covered by the turbine's blades as they rotate) is perpendicular to the direction of the wind.

3. The predominant wind direction is the direction from which the wind blows most frequently in a particular location. For a wind turbine to be most effective, it should be oriented so that its swept area is perpendicular to the predominant wind direction.

4. Therefore, a rotor installed in a fixed orientation with the swept area perpendicular to the predominant wind direction is typically a characteristic of a Horizontal Axis Wind Turbine (HAWT).