Large eddy simulation of fluid/structure interaction of two in-line cylinders in a turbulent flow
Résumé
This work reports the numerical results obtained by the CEA with the in-house CFD
software TrioCFD within the framework of an OECD/NEA benchmark focusing on
the fluid/structure interaction issue. The experimental facility consists of two in-line
cantilever cylinders placed in a thin channel and subjected to vibrations under the effect of a turbulent flow1
. Three kinds of calculations using the wall-resolved large eddy
simulation approach are considered: first, a simulation with fixed cylinders; second, a
one-way coupling with imposed displacement of the cylinders; and third, a more realistic two-way coupling. The first case is used to conduct a sensitivity analysis of the
mesh size using two tetrahedral meshes called respectively coarse (16 million elements)
and fine (85 million elements). Unlike the coarse mesh, the average and RMS velocity
profiles computed with the fine mesh downstream of the cylinders are found to be in
good agreement with the experiment, as shown in Fig. 1(a). In the one-way coupling,
a small harmonic displacement corresponding to a vibration mode of a clamped-free
Euler-Bernoulli beam is imposed on the cylinders. An arbitrary Lagrangian-Eulerian
method is employed to solve the fluid/structure interaction involving moving boundaries. In the two-way coupling strategy, a reduced Euler-Bernoulli beam model is
coupled to the fluid software by using a partitioned time marching algorithm. At the
time of the present abstract, the results of the simulations with the two-way coupling
method are still pending. However the average and RMS velocities, as well as the
spectra of velocity, pressure, and cylinder acceleration spectra at given points will be
further compared to that recorded experimentally
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