Difference between 'Thermodynamics and Heat Transfer'?
Thermodynamics mainly deals with the transfer of energy in form of heat or work between systems and surroundings with other systems in form of either heat or work in equilibrium conditions. When there is change in one state, which was in equilibrium state and starting to change in other equilibrium state, this information helps to determine heat or work interactions due to this process. Heat transfer deals with non equilibrium heat exchange or transfer due to temperature gradient while in thermodynamics, during thermal equilibrium (No temperature gradient) no heat exchange is possible.
How is natural convection different from forced convection ?
In natural convection, the movement of the fluid is due entirely to density gradients within the fluid (e.g. hot air rises over cold air). There is no external device or phenomenon which causes fluid motion. In forced convection, the fluid is forced to flow by an external factor - e.g. wind in the atmosphere, a fan blowing air, water being pumped through a pipe. Typically heat transfer under forced convection conditions is higher than natural convection for the same fluid.
Though units for pressure and stress are same (i.e N/mm2)What is the difference between stress and pressure?
Stress is restoring force developed in the body due to any tensile, compressive or any other force per unit area and on the other hand pressure is force applied on a body per unit area.