The paper deals with the simulation of the dynamic nonlinear behaviour of seabed anchored submerged floating tunnels (SFTs) under environmental excitation, by addressing the problem of vortex induced excitation. A model based on the ‘fluid oscillator’ approach is proposed, tailored to be coupled to a geometrically non linear FE developed, for the anchor bars, in a previous work. The approach allows for representing the entire anchoring bar, thus reducing the computational effort required for global modelling of the SFT. In this light, mainly based on a lumped fluid oscillator model, a computationally more efficient approach is here sought in the form of a continuous model (Distributed Vortex Layer - DVL). This consists of a distributed ‘aerodynamic’ mass which is connected to the structural element and to a fixed reference system by distributed non linear spring-dashpot elements. Governing equations of motion are obtained substituting Galerkin-type decomposition of both the structure and the aerodynamic mass displacements; global equations of motion are integrated by a step-by-step procedure based on the Newmark method. Validations of the numerical model are finally given, regarding experimental results obtained for two basic structures: an elastically suspended rigid cylinder and a long slender cylinder.

Vortex Induced Vibration in Submerged Floating Tunnels: DVL a Distributed Vortex Layer Model

PEROTTI, FEDERICO;DI PILATO, MARIA GRAZIA
2009-01-01

Abstract

The paper deals with the simulation of the dynamic nonlinear behaviour of seabed anchored submerged floating tunnels (SFTs) under environmental excitation, by addressing the problem of vortex induced excitation. A model based on the ‘fluid oscillator’ approach is proposed, tailored to be coupled to a geometrically non linear FE developed, for the anchor bars, in a previous work. The approach allows for representing the entire anchoring bar, thus reducing the computational effort required for global modelling of the SFT. In this light, mainly based on a lumped fluid oscillator model, a computationally more efficient approach is here sought in the form of a continuous model (Distributed Vortex Layer - DVL). This consists of a distributed ‘aerodynamic’ mass which is connected to the structural element and to a fixed reference system by distributed non linear spring-dashpot elements. Governing equations of motion are obtained substituting Galerkin-type decomposition of both the structure and the aerodynamic mass displacements; global equations of motion are integrated by a step-by-step procedure based on the Newmark method. Validations of the numerical model are finally given, regarding experimental results obtained for two basic structures: an elastically suspended rigid cylinder and a long slender cylinder.
2009
Strait Crossing 2009
978-82-92506-69-1
vortex induced vibration; submerged floating tunnel
File in questo prodotto:
File Dimensione Formato  
DiPilato_Perotti Strait Crossings 2009.pdf

Accesso riservato

: Altro materiale allegato
Dimensione 148.01 kB
Formato Adobe PDF
148.01 kB Adobe PDF   Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11311/568811
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact