Fig. 2

Evolution of \(R{i_f}\) as a function of \(\zeta\) for the four \({\Phi _m}\left( \zeta \right)\) formulations reported in Table 1; only the Businger–Dyer formulation converges to the expected value.

Evolution of \(R{i_f}\) as a function of \(\zeta\) for the four \({\Phi _m}\left( \zeta \right)\) formulations reported in Table 1; only the Businger–Dyer formulation converges to the expected value.