In laminar flow over a flat plate, how does the thermal boundary layer thickness, δt vary with respect to the distance, x, from the leading edge?
1
\(\delta_t \propto \frac{1}{\sqrt{x}}\)
2
\(\delta_t \propto x\)
3
\(\delta_t \propto x^2\)
4
\(\delta_t \propto \sqrt{x}\)