To change the physical parameters of the radiator (e.g., number of tubes, fin height, etc.), open src/main.cpp and update the following variables:
const double numTubes = 60;
const double tubeHeight = 0.00156;
const double tubeWidth = 0.0246;
const double finDistance = 0.00158;
const double finHeight = 0.1188;
const double finWidth = 0.0246;