Which of the following describes laminar flow?

Laminar flow is characterized by a smooth and uniform motion of fluid particles. In laminar flow, the fluid moves in parallel layers, with minimal disruption between them, creating a streamlined flow pattern. This is typically observed at lower velocities and in conditions where the viscous forces dominate over inertial forces.

The uniformity in laminar flow results in predictable velocity profiles and typically low friction losses, making it a key consideration in engineering applications where efficient fluid transport is necessary. In many cases, laminar flow can be identified through a Reynolds number of less than approximately 2000, although this can vary depending on the specific flow conditions and geometry.

Other options describe different flow regimes. Chaotic and irregular flows represent turbulent conditions, where fluid particles move randomly and create eddies, while swirling motions indicate the presence of vortices typical in turbulent flows. Consistent turbulence would also apply to turbulent flow, where flow characteristics are inherently unstable and fluctuate significantly. Thus, option B accurately defines laminar flow by emphasizing its smooth and uniform attributes.