% F = COLEBROOK(R,K) fast, accurate and robust computation of the
% Darcy-Weisbach friction factor F according to the Colebrook equation:
% - -
% 1 | K 2.51 |
% --------- = -2 * Log_10 | ----- + ------------- |
% sqrt(F) | 3.7 R * sqrt(F) |
% - -
% R : Reynolds' number (should be >= 2300).
% K : Equivalent sand roughness height divided by the hydraulic
% diameter (default K=0).
% F : Friction factor.
% R, K and F are either scalars or compatible arrays.
% Around machine precision forall R > 3 and forall K>=0,
% i.e. forall values of physical interest.
% EXAMPLE: F = colebrook([3e3,7e5,1e100],0.01)
This m-file is more efficient than the solution of the Colebrook equation via the Lambert W-function, or the simple approximations.
PS: For the first submission of this m-file, the author accidentaly uploaded a test version. This resubmission should be the correct one.
Didier Clamond (2020). colebrook.m (https://www.mathworks.com/matlabcentral/fileexchange/21990-colebrook-m), MATLAB Central File Exchange. Retrieved .