How is velocity pressure defined?

Velocity pressure is defined as the pressure created by a fluid in motion. When a fluid is flowing, it carries kinetic energy, and this energy manifests as velocity pressure. It is a key concept in fluid dynamics and HVAC systems, as it helps to determine how air and other fluids will behave when moved through ducts and other components.

In HVAC applications, understanding velocity pressure is important for calculating airflow, designing duct systems, and ensuring that systems operate efficiently. For instance, when air moves through a duct, the velocity pressure can influence draft and sound levels, which are critical for comfort and system performance.

The other choices refer to different concepts: pressure at rest, temperature effects, and density do not relate specifically to the motion of the fluid itself, which is central to the definition of velocity pressure. This distinction is crucial for HVAC technicians working to optimize system performance and troubleshoot issues effectively.