Sammenlign metoder

	Grensesjiktteori	Reynolds-Averaged Navier-Stokes
Fagfelt	Fluiddynamikk	Fluiddynamikk
Familie	Process / pipeline	Process / pipeline
Opprinnelsesår	1904	1895
Opphavsperson	Ludwig Prandtl	Osborne Reynolds
Type	Analytical framework and approximation method	Computational turbulence modeling approach
Opprinnelig kilde	Prandtl, L. (1904). Über Flüssigkeitsbewegung bei sehr kleiner Reibung. In Verhandlungen des 3. Internationalen Mathematiker-Kongresses in Heidelberg (pp. 484-491). Teubner.	Reynolds, O. (1895). On the dynamical theory of incompressible viscous fluids and the determination of the criterion. Philosophical Transactions of the Royal Society A, 186, 123-164.
Alias	BL theory, Prandtl boundary layer, viscous layer	RANS, Reynolds-averaged flow simulation
Relaterte	5	5
Sammendrag	Boundary Layer Theory is the analytical and approximate framework for understanding viscous flow near solid surfaces, pioneered by Ludwig Prandtl in 1904. The central insight is that at high Reynolds numbers, viscous effects are confined to a thin layer near walls (the boundary layer), while the flow outside remains essentially inviscid. This separation enables powerful approximations: the boundary layer equations reduce the full Navier-Stokes to a parabolic system solvable via streamwise marching, yielding analytical or semi-analytical solutions for many practical cases. Boundary layer theory remains fundamental to aerodynamics, hydrodynamics, and heat transfer.	The Reynolds-Averaged Navier-Stokes (RANS) equations represent a time-averaged form of the Navier-Stokes equations developed by Osborne Reynolds in 1895. This approach decomposes turbulent flow into mean and fluctuating components, enabling practical simulation of turbulent flows by modeling turbulent stresses rather than resolving all scales. RANS remains the most widely used computational fluid dynamics method in engineering applications due to its computational efficiency.