手法を比較

	境界層理論	Smoothed Particle Hydrodynamics
分野	流体力学	流体力学
系統	Process / pipeline	Process / pipeline
提唱年	1904	1977
提唱者	Ludwig Prandtl	Monaghan John & Lucy Leon
種類	Analytical framework and approximation method	Meshfree particle method
原典	Prandtl, L. (1904). Über Flüssigkeitsbewegung bei sehr kleiner Reibung. In Verhandlungen des 3. Internationalen Mathematiker-Kongresses in Heidelberg (pp. 484-491). Teubner.	Lucy, L. B. (1977). A numerical approach to the testing of the fission hypothesis. The Astronomical Journal, 82(12), 1013-1024.
別名	BL theory, Prandtl boundary layer, viscous layer	SPH, particle hydrodynamics
関連	5	5
概要	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.	Smoothed Particle Hydrodynamics (SPH) is a meshfree particle method for simulating fluid dynamics, developed independently by Lucy in 1977 and Gingold and Monaghan in 1977. Rather than discretizing on a fixed grid, SPH represents fluids as collections of particles that carry mass, momentum, and energy. Each particle interacts with neighbors within a kernel support radius, enabling natural handling of free surfaces, large deformations, and multiphase flows without remeshing. SPH has become indispensable for simulations involving violent flows, impacts, and complex interfaces.