(a)

(b)

(c)

Figure 11: Transfer function $H_{\text{transversal}}(\omega )$; modulus versus frequency (a), phase versus frequency (b); coherence between $f_{\text{transversal}}$ and $u_{\text{central}}$ versus frequency (Hz) (c); in still water, and for 3.4 m/s and 4.9 m/s fluid velocities.