Neutral-Stability

ModelingToolkit implementation of the aerodynamic resistance to dry deposition from Seinfeld & Pandis (2006), Atmospheric Chemistry and Physics, 2nd ed., Chapter 19 (Dry Deposition), Eq. 19.14. Computes the aerodynamic resistance r_a [s/m] -- the resistance to turbulent transport of a depositing species through the surface layer, from the reference height z down to the roughness height z_0 -- under neutral atmospheric stability. Eq. 19.14, r_a = ln(z/z_0)/(kappa*u_star), is the integral of the neutral-stability logarithmic wind profile: r_a falls inversely with the friction velocity u_star (stronger turbulence carries the species down faster) and with the logarithm of the height ratio z/z_0 (a rougher surface, larger z_0, is more efficiently coupled to the atmosphere and presents less aerodynamic resistance). Migrated from AtmosphericDeposition.jl@e4468c79 src/seinfeld_pandis_ch19.jl:106 (the AerodynamicResistance @component). Purely algebraic: no differential states, a single explicit equation.