Transportteori

Transportteori (English: transport theory) is a multidisciplinary field that studies the movement and exchange of mass, energy, momentum, information or agents within physical, biological, economic or engineered systems. The term covers both the mathematical description of transport processes and the applied study of systems that transport particles, radiation, fluids, vehicles or commodities.

Historically, transport theory grew from kinetic theory and radiative transfer in physics and from classical diffusion and fluid mechanics. In mathematics it developed into a broad set of partial differential equations and variational problems; in economics and operations research it includes models of flows, networks and optimal allocation.

Major branches include kinetic and Boltzmann-type theories for particle transport, radiative transfer for photons and neutrons, diffusion and advection–diffusion models for mass and heat, and optimal transport theory concerned with cost-minimizing redistribution of resources. Common mathematical tools are integro-differential equations, stochastic processes, conservation laws, and numerical methods such as Monte Carlo simulation, finite element and finite volume schemes.

Applications span nuclear engineering, astrophysics, semiconductor design, climate modeling, biological transport phenomena, urban traffic planning and logistics. Core concepts include transport coefficients, mean free path, flux, scattering and absorption, boundary conditions and steady versus transient regimes. Transportteori interfaces with control theory, statistics and optimization, and remains an active area of research for modeling complex, multiscale systems.