clc;clear;

diameter = 2e-2;
Dab = 4;
Dbc = 4;
Dca = 8;

radius = diameter/2;
effictive_radius = 0.7788*radius;
Deq = (Dab*Dbc*Dca)^(1/3);

La = 2e-7*log(Deq/effictive_radius)