OHTC of part of pipe in contact with ground

Overall heat transfer coefficient (OHTC) of the pipe in contact with ground.

Symbol
$U_{ground}$
Unit
W/(K.m$^2$)
Formulae
$\frac{1}{\frac{D_{ref}}{D_{wall} U_{wall}} + \frac{D_{ref}}{D_{in} h_{in}} + \frac{D_{ref}}{D_{ext} h_{ground}}}$Carslaw & Jaeger
$\frac{1}{\frac{1}{h_{ground}} + \frac{1}{h_{amb}}}$Morud & Simonsen / OTC 23033
$\frac{1}{\frac{D_{ref}}{D_{wall} U_{wall}} + \frac{1}{h_{buried}} + \frac{1}{h_{amb}} + \frac{D_{ref}}{D_{in} h_{in}}}$Ovuworie
Related
$D_{ext}$
$h_{buried}$
$U_{wall}$
OHTC of pipe wall [W/(K.m$^2$)]
Used in
$U_{partially}$