“…Similarly to multipole expansion for the quasi-orthogonal eigenfunctions, terms α m,j , β m,j , γ l m,j , γ m,j , δ l m,j and δ m,j are determined by matching the boundary conditions in Equations (4b)-(4e). According to Prieto and Cimmino [36], the values of α 0,j = T 0 and γ 0,j , α m,j and β m,j are set to 0. Here, the authors note that, for the present method, keeping all terms expressed in Equation ( 10) stabilizes the integration in Equation ( 8), where terms γ 0,j and α m,j , β m,j are small when matching the far-field boundary with r e = 100 m. For more details concerning the evaluation of eigenvalues and coefficients to match the boundary conditions in both problems, readers are referred to Prieto and Cimmino [36].…”