In parallel flow, 𝜃 ̃0(0) is independent of 𝜃 ̃1(0). From , it is also known that the coefficients in Eq. (C1) are independent of the boundary conditions 𝜃 ̃𝑗-1 (0) (𝑗 = 1, 2, 3). Thus, for Eq. (C4) to always be an equality, the following conditions must be satisfied: Therefore, it is concluded that Zuritz's solution for TTHE-HL (Eq. ( ) from ), is generally not correct for 𝑇 1 . These authors were unable to find any erratum or corrigendum regarding this solution. (forced convection), calculated (in this work) using the analytical solutions of Zuritz and that of the present work.