Vortex-Induced Vibration (VIV) Around a Cylinder at Low Reynolds Numbers: The Lock-In phenomenon.

FILIPPINI GERMAN; NIGRO NORBERTO; STORTI MARIO; PAZ RODRIGO

SANTA FE

Congreso; ENIEF 2006; 2006

ASOCIACION ARGENTINA DE MECANICA COMPUTACIONAL

In this paper some numerical results for vortex-induced vibrations (VIVs) of a cylinder at low Reynolds number are presented. The main goal of these preliminary results is the capturing of synchronization/lock-in phenomenon when Reynolds number is swept for low dimensionless mass ratiophenomenon when Reynolds number is swept for low dimensionless mass ratio (m ' 153.3524). This fluid-structure interaction problem (FSI) contains three main problems to be solved, the computational fluid dynamics (CFD), the computational mesh dynamics (CMD) and the multi-body dynamics (MBD). In this work this last problem is oversimplified to a single body dynamics, the cylinder. A stabilized ALE (Arbitrary Lagrangian-Eulerian) formulation is used to solve the incompressible laminar Navier Stokes equations. The cylinder is considered as a rigid body and it is free to vibrate along the vertical (transverse) direction and it is fixed to move in the horizontal one. The mesh dynamics may be solved in general by a global optimization strategy, however, in some special cases, a simple ad-hoc procedure may be adopted. For each sub-problem a second order accurate in time scheme is adopted. The fluid-structure interaction problem is solved with a strong coupling using a fixed point iteration strategy. It consists of an additional loop over the three problems forcing the convergence inside each time step. Hysteretic and vortex-shedding modes are two additional topics that deserve special attention and they are going to be included in a future work.m ' 153.3524). This fluid-structure interaction problem (FSI) contains three main problems to be solved, the computational fluid dynamics (CFD), the computational mesh dynamics (CMD) and the multi-body dynamics (MBD). In this work this last problem is oversimplified to a single body dynamics, the cylinder. A stabilized ALE (Arbitrary Lagrangian-Eulerian) formulation is used to solve the incompressible laminar Navier Stokes equations. The cylinder is considered as a rigid body and it is free to vibrate along the vertical (transverse) direction and it is fixed to move in the horizontal one. The mesh dynamics may be solved in general by a global optimization strategy, however, in some special cases, a simple ad-hoc procedure may be adopted. For each sub-problem a second order accurate in time scheme is adopted. The fluid-structure interaction problem is solved with a strong coupling using a fixed point iteration strategy. It consists of an additional loop over the three problems forcing the convergence inside each time step. Hysteretic and vortex-shedding modes are two additional topics that deserve special attention and they are going to be included in a future work.