The continuity equation is a fundamental principle in fluid dynamics that expresses the conservation of mass in a fluid flow system. It states that the mass flow rate of a fluid must remain constant from one cross-section of a pipe to another, assuming steady flow and incompressibility of the fluid.
The Eulerian perspective focuses on specific locations in the space through which the fluid flows, observing how fluid properties change over time at these fixed points. In contrast, the Lagrangian perspective follows individual fluid particles as they move through space and time, tracking changes in their properties along their path.
A steady-state flow process is a condition in which the fluid properties at any given point in the system do not change over time, ensuring that the mass, energy, and volume flow rates remain constant throughout the system. This concept is crucial in engineering applications for simplifying the analysis of fluid systems, as it allows for the assumption of time-invariant conditions, leading to more straightforward calculations and predictions.
Mass flux is a measure of the mass of a substance passing through a unit area per unit time, crucial for analyzing flow in fluid dynamics and heat transfer. It helps understand and quantify the transport of mass in various systems, from atmospheric science to engineering applications.