type HeatTransferBoundary = enumeration(UWTuDFF "Uniform wall temperature in developed fluid flow (UWT+DFF)", UHFuDFF "Uniform heat flux in developed fluid flow (UHF+DFF)", UWTuUFF "Uniform wall temperature in undeveloped fluid flow (UWT+UFF)", UHFuUFF "Uniform heat flux in undeveloped fluid flow (UHF+UFF)");