# What happens in Thermal boundary layer in a flow with cooled plate?

All the notes on Thermal boundary layer(TBL) explains the growth of TBL over a heated flat plate ie cooler fluid is flowing over a hotter plate (heat is flowing from the plate to the fluid).

How does the thermal boundary layer develop over a chilled plate, where hot fluid flows over a chilled plate. Also, Can you please direct me to any notes or text that deal with this?

Revers of a hot plate. the smaller the $$P_r=\frac{momentum \ diffiusity}{thermal\ diffiusity},$$

the thicker the TBL however the heat gradient is descending as opposed to a hot plate.

I will try to find links later, I got to run.

• thank you. If you could find any link that would be really great. Commented Dec 27, 2020 at 17:04

I don't know why you expect the development is any different. If you see the main page at Wikipedia about Thermal boundary layer the image is one of cooler fluid over a hotter plate.

In the opposite case (hotter fluid) the only difference is that the temperature gradient is mirrored across the vertical axis. However you still have high gradient near the wall, and lower gradient further away.

The only main difference, that you might see (although not often considered), is if gravity and the changing density is considered.

• yeah that's what I thought too...but I just couldn't accept it without somekind of proof..and when I tried to find some literature relating to it...I was hard pressed to find any. The principal is used in many places..gas turbine blades...after burners ...even hot plasma containers(but here it's radiation I guess). Even so the introduction is always through flow over hot plate and no mention of what happens if it's reverse d. Commented Dec 27, 2020 at 19:40