 ## Fluids

• vsjay3
Subscriber

Hi All,

In Ansys Fluent, I am modelling a pipe (with water flowing inside) passing though a soil block. As boundary conditions, I assigned top wall surface of soil block a fixed temperature of 70C and bottom wall a fixed temperature of 31.4C. However, when I ran the simulation and plotted temperature along the vertical depth of the block in a xy plot , I found something interesting. If I plot total temperature against depth, then the temperature of top and bottom surface values are not equal to 70C and 31.4C. Instead they were 68C and 31.6C. However, if I plot static temperature against depth, then the temperature of top and bottom surface values are indeed equal to 70C and 31.4C.

I am not sure why this is happening. What exactly is the difference between total and static temperature here? So does this mean I have to use static temperature when plotting and avoid using total temperature? I just want to get temperature variation with depth of solid block .

Thank you!

• Murari Iyengar
Ansys Employee
Hi vsjay3 The total temperature is the temperature of the fluid when it is brought to rest adiabatically. Hence, it is the sum of static and dynamic temperature((v^2)/(2*Cp)) where v is the velocity and Cp is the specific heat. The static temperature is the actual temperature of the fluid. This is why you are getting varied results for both the cases. In case you are interested in the actual fluid temperature, go with static temperature.

• DrAmine
Ansys Employee
• vsjay3
Subscriber

If I want to plot temperature profile of coolant in the pipe (while coolant is flowing), do I use static temperature then?
Thank you very much!
• DrAmine
Ansys Employee
If I will need to plot the temperature of my coolant, I will then only think about the static temperature.
• vsjay3
Subscriber
Thank you very much !
• DrAmine
Ansys Employee
Welcome! 