What process involves expelling fluid or gas after moving control surfaces?

The process that involves expelling fluid or gas after moving control surfaces is characterized as an Open Loop system. In an Open Loop control system, the output is not measured or fed back into the system for correction. Instead, it operates based on a predetermined set of instructions or inputs, such as moving control surfaces to direct a fluid or gas flow. Once these actions are initiated, the output occurs without further adjustments based on the results of those changes.

This means that in the context of controlling fluid or gas expulsion, the system moves the control surfaces and allows the expulsion to happen as a direct result of those movements, without taking into account any feedback from the environment or the expulsion itself. This can be effective in systems where the relationship between input and output is well understood and does not require further adjustments for optimal performance.

In contrast, Closed Loop systems utilize feedback to continually adjust the output based on the measured performance, while Feedback Loop systems specifically emphasize the role of feedback in adjusting actions. Control Loop is a more general term that can apply to both Open and Closed Loop systems but does not specifically denote the absence of feedback that defines an Open Loop system.