Is a laminar or turbulent boundary layer better for heat transfer from the surface to the environment?

Turbulent flow (High Reynold’s Number) makes the thermal boundary layer small which allows for better (faster cooling). Laminar flow (Low Reynolds #) has thick thermal & hydrodynamic boundary layer which is bad for cooling


  • Thermal Boundary Layer: Fluid through which the velocity varies from zero at the surface to a finite value u_∞ associated with the flow.