Final answer:
In the given scenario, a Newtonian fluid flowing steadily and smoothly between two vertical parallel plates is described as having a laminar flow. This type of flow is characterized by fluid moving in layers without mixing,
which is consistent with option C. Laminar flow.
Step-by-step explanation:
The described scenario of a Newtonian fluid flowing steadily downward between two vertical, infinite, parallel plates with a fully developed and laminar flow most accurately fits option C. Laminar flow.
In this type of flow, the fluid moves in smooth layers with minimal mixing. The characteristics of laminar flow include each layer of fluid sliding past the adjacent layers with little to no disruption to the flow pattern.
The definition of viscosity and its measurement often involves experiments where fluid is sheared between two plates, as seen in the references provided.
The velocity profile that develops in the fluid layers is continuous from the moving plate down to the stationary plate, confirming that it's a laminar flow scenario.
Flow can be characterized as laminar or turbulent based on a dimensionless number called the Reynolds number. Laminar flow tends to occur at low Reynolds numbers, where the flow is orderly, while higher Reynolds numbers may lead to turbulent flow.
The given case does not indicate high velocities or a disruptive flow, further substantiating that the fluid exhibits laminar characteristics.