Issam Bahadur
A new reduced-order model for vortex-induced vibration (VIV) of bluff bodies is developed from the momentum equation of an elastically mounted cylinder. The formulation offers a physical interpretation of its parameters, providing deeper insight into the underlying mechanisms of VIV. In its simplified form, the model reduces to a classical Van der Pol-type wake oscillator, with the lift coefficient expressed as a function of the wake displacement, velocity, and acceleration, C L ( q , q ˙ , q ̈ ) . The model’s accuracy is evaluated through validation against experimental and finite element method data for four different mass ratios. Results show that the proposed formulation successfully reproduces key characteristics of VIV, including displacement amplitude, reduced frequency, phase transition, and total lift coefficient, with overall good agreement across all cases. This establishes a robust and physically grounded framework for further exploration of VIV dynamics and stability.