A Navier-Stokes solver based on Cartesian structured finite volume
discretization with embedded bodies is presented. Fluid structure
interaction with solid bodies is performed with an explicit
partitioned strategy. The Navier-Stokes equations are solved in the
whole domain via a Semi-Implicit Method for Pressure Linked Equations
(SIMPLE) using a colocated finite volume scheme, stabilized via the
Rhie-Chow discretization. As uniform Cartesian grids are used, the
solid interface usually do not coincide with the mesh, and then a
second order Immersed Boundary Method is proposed, in order to avoid
the loss of precision due to the staircase representation of the
surface. This fact also affects the computation of fluid forces on the
solid wall and, accordingly, the results in the fluid-structure
analysis. In the present work, first and second order approximations
for computing the fluid forces at the interface are studied and
compared. The solver is specially oriented to General Purpose Graphic
Processing Units (GPGPU) hardware and the efficiency is
discussed. Moreover, a novel submerged buoy experiment is also
reported. The experiment consists of a sphere with positive buoyancy
fully submerged in a cubic tank, subject to harmonic displacements
imposed by a shake table. The sphere is attached to the bottom of the
tank with a string. The position of the buoy is determined from video
records with a Motion Capture algorithm. The obtained amplitude and
phase curves allow a precise determination of the added mass and drag
forces. Due to this aspect the experimental data can be of interest
for comparison with other fluid-structure interaction codes. Finally,
the numerical results are compared with the experiments, and allows
the confirmation of the numerically predicted drag and added mass of
the body.
Experimental video at resonance conditions
Description of the buoy fluid structure interaction problem