Answer:
Option A is correct.
Eddies due to enhanced mixing of fluid
Explanation:
Turbulent thermal conductivity is thermal conductivity that arises from the turbulent flow of fluids. It comes into play when a particukar fluid moves into turbulent regiom of flow where flow is no longer orderly and streamlines aren't discernable with the fluid layers all warping into one another forming vortices.
It is represented as K and is shown mathematically through the heat flux at turbulent flow
q = vCρT' = - K (∂T/∂y)
where
K = turbulent thermal conductivity
T' = the eddy temperature relative to the mean value,
C = Heat capacity the fluid
q = the rate of thermal energy transport by turbulent eddies.
The physical mechanism that cause turbulent thermal conductivity are similar to the causes of turbulent flow of fluids.
This includes sharp changes in fluid pressure and velocity of flow which is evident in eddies that come about in the enhanced mixing of fluids.
Hope this Helps!!!
