What is indicated by streamlines being perpendicular to equipotential lines in a flow net?

When streamlines are perpendicular to equipotential lines in a flow net, it signifies that flow paths are established, indicating the direction of fluid movement in the system. This relationship illustrates the fundamental principles of fluid dynamics, where flow is driven from high potential (energy) areas to low potential areas, demonstrating that water moves along the steepest gradient in a path that is dictated by the configuration of the equipotential lines.

In a flow net, streamlines represent the trajectory that water particles would follow, while equipotential lines represent points of equal hydraulic potential. The perpendicularity of these two lines indicates that at any given location, the flow direction is not only defined but also optimal in terms of energy efficiency, as water will move swiftly through the path created by the equilibrium of pressures along the equipotential lines.

This understanding is crucial for civil engineering applications, particularly in groundwater management and hydraulic engineering, where knowing the flow paths enables effective design and analysis of drainage systems, slope stability, and other related structures.