השוואת שיטות

	תורת שכבת הגבול	סימולציית זרימה טורבולנטית מנותקת (Detached Eddy Simulation)
תחום	דינמיקת זורמים	דינמיקת זורמים
משפחה	Process / pipeline	Process / pipeline
שנת המקור	1904	1997
הוגה השיטה	Ludwig Prandtl	Philippe Spalart
סוג	Analytical framework and approximation method	Hybrid turbulence modeling approach
מקור מכונן	Prandtl, L. (1904). Über Flüssigkeitsbewegung bei sehr kleiner Reibung. In Verhandlungen des 3. Internationalen Mathematiker-Kongresses in Heidelberg (pp. 484-491). Teubner.	Spalart, P. R., Jou, W. H., Strelets, M., & Allmaras, S. R. (1997). Comments on the feasibility of LES for wings, and on a hybrid RANS/LES approach. Advances in DNS/LES, 1, 4-8.
כינויים	BL theory, Prandtl boundary layer, viscous layer	DES, hybrid RANS-LES
קשורות	5	5
תקציר	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.	Detached Eddy Simulation (DES) is a hybrid turbulence modeling approach introduced by Spalart in 1997 that combines the computational efficiency of RANS in attached boundary layers with the accuracy of LES in separated wake regions. By automatically switching between RANS and LES based on local grid spacing and turbulence length scales, DES provides superior predictions for flows with large separations, shear layers, and vortex shedding at a cost between pure RANS and pure LES. DES has become the standard method for complex aerospace applications involving separation and transient phenomena.