Simulating the dynamic response of OHTL cables with an updated equivalent oscillator model

Vortex-Induced Vibration (VIV) is a complex phenomenon that induces periodic structural oscillations. The goal of the research is developing a reliable model capable of simulating the response of Over Head Trasmission Line (OHTL) to VIV, also in turbulent flow conditions. With this aim, the equivalent oscillator model (EOM) was updated, incorporating both structural flexibility and turbulence modeling in time domain. Initially, the model parameters were optimized using wind tunnel experimental data, extending its capability to simulate conditions with higher Scruton numbers. A comparison with established wake oscillator models was also performed, demonstrating the capability of the EOM in simulating accurately the initial branch and maximum vibration amplitude. Subsequently, a modal approach was introduced to simulate the response of flexible cylinders in laminar flow. Experimental comparison showed a good reliability, achieving a mean absolute relative error of 3.89% in estimating the maximum vibration amplitude across the tested modes. The model was then improved to simulate real cables, limiting the number of oscillators to reach a trade-off between computational efficiency and accuracy. In the end, comparisons with an Energy Balance Principle (EBP) software demonstrated strong agreement between the two methodologies in both laminar and turbulence conditions. Results obtained with a 15% turbulence intensity showed a maximum absolut error of 10.5%. These advancements underscore the model’s robustness and reliability for real-world applications, allowing for more in-depth and comprehensive results with respect to traditional energy balance approaches.