Discussion:

 

In the universe which we live, there are three types ways that heat is transferred from one object to another.  The types of heat transfer are; conduction in solids, convection of fluids (liquids or gases), and radiation through a medium. Conduction is when heat is exchanged through two objects that are in contact with each other, and neither material is moving with respect to the other.  When there is a temperature difference in a system, heat always moves from higher temperature to a lower one. Heat flows from the warmer object until both bodies are isometric. In liquids and gases, convection is usually the most efficient in which heat is transmitted. In convection warmer portions of a body of liquid or gas rise to cooler areas in the liquid or gas and e. As this happens, cooler liquid or gas takes the place of the warmer areas which have risen higher.

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In our problem, we had a cylindrical fin coming out of a wall that was exposed to a constant heating of 50 MW/m^3, with the ambient temperature of 298.15 Kelvin.   Since the fluid temperature is less than the surface, as it flows over the surface the warmer air on the surface rises and is replaced by the cooler air of the flow. This causes a cooling effect on the surface, and that is why the temperature gradient deceased as we added a fluid flow over our fin.

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The Nusselt number (Nu) is the ratio of heat transferred through convection to the heat transferred through conduction. This describes how the heat transfers with higher gradient due to the fluid’s motion. With our particular case there is a laminar flow flowing across a cylindrical fin that is attached to a wall with a constant temperature, and that also has a constant heat generation.