Abstract:
The vortex-induced vibration (VIV) phenomenon has drawn the attention of
researchers in Engineering for several decades. An example is the riser used
for petroleum exploration, in which it is subjected to marine flows that may
cause oscillations due to vortex shedding. In this paper, numerical analyses
of the phenomena that occur in the interaction among flows at low Reynolds
numbers and elastically mounted cylinders are presented. The simulation is
carried out by using the numerical model Ifeinco that uses a semi-implicit
two-step Taylor-Galerkin method to discretize the Navier-Stokes equations
and the arbitrary Lagrangean-Eulerian formulation to follow the cylinder
motion. The rigid body motion description is calculated by using the
Newmark method. Firstly, the characteristics of the vortex generation
process for the fixed cylinder are analyzed. In this case, the Strouhal
number, the mean drag and the RMS lift coefficients for Reynolds numbers
ranging from 90 to 140 are shown. Afterwards, an analysis of a flexible
supported cylinder (with a spring and a damper) in transverse direction
subject to flows with Reynolds numbers ranging from 90 to 140 is carried
out. The cylinder displacement and the vibration frequencies are studied;
the synchronization between the vortex shedding and the vibration
frequency (lock-in) is analyzed. Similar results to the experimental ones
developed by Anagnostopoulos and Bearman (1992) were obtained in this
study.
