What does it mean to "impinge" in the context of flow dynamics?

In the context of flow dynamics, to "impinge" means to strike or attack directly, typically referring to how fluid flow interacts with surfaces or objects in its path. When a fluid impinges upon an object, it can create localized forces and alter flow patterns. For instance, when water flows towards a barrier, the point at which it hits the barrier is termed the "impingement point." This interaction can lead to important engineering considerations, such as erosion, turbulence, and pressure differences that influence the design of structures in hydraulic environments.

While the other options mention related concepts in flow dynamics, they do not capture the specific action of direct impact that the term "impinge" conveys. For example, following the curve of a channel deals with the path of fluid rather than impact, collecting debris relates to what might be swept along by the flow, and diffusing energy refers to the spread of energy across a larger area, which is more about reducing the intensity of flow rather than striking directly.