SF_18
Function SF_18 provides the shape factor ([m] or [ft]) for a thin strip completely buried in a semi-infinite medium and parallel to the surface.
Inputs:
w = depth of strip below surface ([m] or [ft])
b = width of strip ([m] or [ft])
L = length of strip ([m] or [ft])
Example: SF = SF_18(w, b, L)
Reference: Wong, H. (1977). Heat transfer for engineers. London: Longman Group Ltd. p. 25.