boundary-layer-theorylisted

# Boundary Layer Theory (aerodynamics/boundary-layer/boundary-layer-theory) Use when the task is flat-plate boundary-layer estimation: thickness, displacement and momentum thickness, skin friction, and the laminar to turbulent transition. ## Domain quick reference - The boundary layer is the thin viscous region next to a surface where the velocity rises from zero at the wall (no-slip) to the edge value U_e. The local Reynolds number Re_x = rho * U * x / mu = U * x / nu sets the flow regime at station x. - Laminar flat plate (Blasius similarity solution, 1908): 99-percent thickness delta = 5.0 * x / sqrt(Re_x), displacement thickness delta* = 1.7208 * x / sqrt(Re_x), momentum thickness theta = 0.664 * x / sqrt(Re_x), shape factor H = delta* / theta = 2.5916, local skin friction Cf = 0.664 / sqrt(Re_x), average Cf over one side = 1.328 / sqrt(Re_x). - Turbulent flat plate (1/7 power law, Re_x up to about 1e7): delta = 0.37 * x / Re_x^(1/5), delta* = delta / 8, theta = 7 * delta / 72, H = 9 / 7 = 1.286, local Cf = 0.0592 / Re_x^(1/5), average Cf = 0.074 / Re_x^(1/5). Above about 1e7 prefer the fully turbulent log-law correlation Cf = 0.455 / (log10 Re_x)^2.58. - Displacement thickness delta* = integral_0^inf (1 - u / U_e) dy is the mass deficit of the layer; the outer flow behaves as if the body were thickened by delta*. Momentum thickness theta = integral_0^inf (u / U_e) * (1 - u / U_e) dy is the momentum deficit. - The von Karman momentum int