Fig. 5

The amplitudes of the w̄, v̄, \(\bar{I}_{M}\), the amount of \(\bar{I}_{M}\) at \(I_{\theta}\) peak, and the phase lag between \(\bar{I}_{M}\) and \(I_{\theta}\) change as the frequency of the sinusoidal forcing increases. The amplitude of v̄ and the phase lag increase, while the w̄ amplitude, \(\bar{I}_{M}\) amplitude, and the absolute amount of \(\bar{I}_{M}\) at \(I_{\theta}\) peak decrease