Purpose <p>The study numerically investigates the vortex-induced vibrations (VIV) of a hollow flexible cylindrical structure, which is subjected to nonuniform flow; linearly and nonlinearly varying flow profiles having three distinct shear parameters (<i>β</i> = 0.25,0.5, and 0.75). The main focus is on the coupled inline and crossflow responses across different shear parameters (<i>β</i>) to understand the effects of nonlinear flow on the dynamic behaviour of the structure.</p> Methods <p>The VIV displacement obtained using the wake oscillator model (WOM) was analyzed using time history analysis, FFT, and mode shape observations to verify the static and dynamic components of the response.</p> Results <p>The results showed that at smaller shear parameters, namely at <i>β</i> = 0.25 and <i>β</i> = 0.5, the inline (IL) dynamic response behaviour was similar for both linear and nonlinear flow cases with minor deviations in amplitude and frequency values. As the shear parameter increased to <i>β</i> = 0.75, nonlinear flow resulted in a significant amplification of vibration amplitudes, mode shapes shift, and a noticeable frequency shift in the IL dynamic VIV response. Inline dynamic vibrations, although having lower amplitudes than crossflow vibrations, showed frequencies about twice that of the crossflow response, which means that there is a possibility of resonance-related damage, especially under nonlinear flow conditions.</p> Conclusion <p>The results highlight the importance of taking nonlinear effects in VIV analysis into account, as they can change the frequency, amplitude, and mode shapes of the vibration response, thus affecting the safety and reliability of offshore structures subjected to fluid-structure interactions.</p>