Quelltermen

Quelltermen, also known as "source terms" or "source functions," are mathematical expressions used in physics and engineering to describe the distribution of sources or sinks within a continuous medium. They are fundamental in fields such as fluid dynamics, electromagnetism, and heat transfer, where they help model phenomena like mass, charge, or energy distribution.

In the context of partial differential equations (PDEs), a source term represents an external influence that affects the evolution of a system. For example, in the heat equation, a source term might account for internal heat generation within a material. Similarly, in Maxwell’s equations, source terms correspond to electric charges and currents, which drive electromagnetic fields.

The concept is particularly important in the Navier-Stokes equations, where source terms can represent body forces (such as gravity) acting on a fluid. By incorporating these terms, the equations can simulate complex behaviors like fluid flow under external influences.

Quelltermen are often introduced as additional terms in governing equations to account for localized effects that cannot be described by the primary variables alone. Their inclusion allows for more accurate modeling of real-world scenarios, where external factors frequently play a critical role.

In computational simulations, source terms are discretized alongside other variables to ensure numerical stability and accuracy. Their proper formulation is essential for obtaining physically meaningful results in simulations of physical systems.