Assessing maximum amplitude and corresponding frequency for vortex-induced vibrations

Øyvind Mortveit Ellingsen (1, 2) , Xavier Amandolese (3, 1) , Pascal Hémon (1)

1 LadHyX - Laboratoire d'hydrodynamique
2 CSTB - Centre Scientifique et Technique du Bâtiment
3 LMSSC - Laboratoire de Mécanique des Structures et des Systèmes Couplés

When designing a structure to withstand vortex-induced vibration (VIV), it is useful to estimate the maximum structural amplitude before doing computationally expensive simulations. This is what is done when following building codes. Most of them use an approximation associated to a given dimensionless frequency. This work aims to evaluate estimates the frequency at maximum amplitude and the amplitude using a coupled system model (structure and wake). Two methods are used in assessing forcing frequency at maximum amplitude and maximum structural amplitude (ry ) is calculated using these values. Method 1 is based on the work of Emmanuel de Langre and corresponds to a linearized estimate of the upper lock-in value. Method 2 is based on scaling two parameters important to the predicted amplitude of motion, namely a frequency detuning proportional to total structural damping and dimensionless forcing.

Keywords: VIV; nonlinear approximation; design estimates

Domains: Fluid mechanics [physics.class-ph]; Engineering Sciences [physics]; Dynamique, vibrations

Øyvind Mortveit Ellingsen, Xavier Amandolese, Pascal Hémon. Assessing maximum amplitude and corresponding frequency for vortex-induced vibrations. Second International Symposium on Flutter and its Application, ISFA 2020, May 2020, Paris, France. ⟨hal-04070863⟩