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This paper presents numerical study of an oval-sail, a bluff-body equipped with a grid all along the span. Suction based flow control is applied to this body that is developed for wind assisted ship propulsion. First, a choice of numerical turbulence model is discussed through results of an oval-sail without suction. Three turbulence models are applied: the Ri j SSG, the Ri j EBRSM and the v2 f model. Then, computations are performed for the oval-sail fitted with suction grid. These last simu- lations are carried out with the low-Reynolds-number Ri j EBRSM turbulence model. The influence of the grid geometry on the oval-sail aerodynamic performances is highlighted. All simulations are carried out for the sail set at zero incidence. The Reynolds number based on the free stream velocity and the profile chord is Re = 5105. Results are compared to available experimental data. [ABSTRACT FROM AUTHOR]

In this paper, a lattice Boltzmann method (LBM) for the fluid-structure interaction of an incompressible neo-Hookean medium is proposed. The objective is to use the lattice Boltzmann method to model the fluid and the solid domains at the same time, and thus avoid coupling two solvers, one for the fluid and one for the structure. The specific case of a neo-Hookean incompressible medium allows us to use a Eulerian formulation for the structure problem, which resembles the Navier-Stokes equation. Then, a macroscopic multiphase equation can be used to model the fluid and structure problems together. Next, the LBM approach is deduced from this macroscopic multiphase formulation of the fluid-structure interaction problem. It consists in extending the LBM to the solid domain by adding a tensor term in the equilibrium function of the collision operator. The effect of the added tensor term is to cancel in the solid domain the viscous fluid constraints and add neo-Hookean constraints. Thus, only the third moment of the LBM is modified, the first two being conserved, and only the constraints in the macroscopic Navier-Stokes equation are changed. The LBM scheme obtained can then model the interaction of a fluid and a structure composed of an incompressible neo-Hookean medium with a single solver for the fluid and the solid. Two additional equations are used, one to track the fluid and solid domains with the Cahn-Hilliard equation, and the other to compute the solid displacement field by a finite-difference scheme. The proposed method is applied successfully on three cases from the literature.