An experimental study of the hydrodynamic behavior of a TLP platform for a 5MW wind turbine with OWC devices

An experimental study of the hydrodynamic behavior of a Tension-Leg Platform (TLP) for a 5MW Wind Turbine, featuring Wave Energy Converter (WEC) devices of the Oscillating Water Column type is presented. The examined triangular platform includes three vertical cylinders at the corners, providing the required buoyancy, each of them surrounded by a thin skirt, open at its lower end, forming the OWC chamber. A central vertical cylinder is included for the wind turbine installation. All cylinders are structurally connected with cylindrical bracing. The hydrodynamic response of the platform in the surge direction is experimentally verified, together with the resulting pressures and air fluxes inside the OWC chamber and the dynamic tensions in the lines of the mooring system

Three-points interfacial quadrature for geometrical source terms on nonuniform grids

International audienceThis paper deals with numerical (finite volume) approximations, on nonuniform meshes, for ordinary differential equations with parameter-dependent fields. Appropriate discretizations are constructed over the space of parameters, in order to guarantee the consistency in presence of variable cells' size, for which $L^p$-error estimates, $1\le p < +\infty$, are proven. Besides, a suitable notion of (weak) regularity for nonuniform meshes is introduced in the most general case, to compensate possibly reduced consistency conditions, and the optimality of the convergence rates with respect to the regularity assumptions on the problem's data is precisely discussed. This analysis attempts to provide a basic theoretical framework for the numerical simulation on unstructured grids (also generated by adaptive algorithms) of a wide class of mathematical models for real systems (geophysical flows, biological and chemical processes, population dynamics)

Numerical and experimental analysis of the hydroelastic behavior of purse seine nets

The paper presents a general three dimensional hydro-elastic tool for the analysis of different types of fishing nets and aquaculture facilities. Flexible net strands are modeled by non-linear truss elements having two nodes. Hydrodynamic loads due to relative motion of the net with the surrounding fluid are computed using the Morison equation. The coupled hydrodynamic-elastodynamic equations are solved using finite element (FE) approximations. Furthermore, experimental data are presented for the drag resistance of a purse seine net, commonly used as fishing tool in the Mediterranean sea. The measurements were conducted in the towing tank of NTUA on a sample of a net. The net was tested in three configurations: vertical, horizontal and inclined at 451. The derived drag coefficients are compared to predictions of the FEM developed model. The vertical submergence behavior of the seine in calm water is also examined, both experimentally and theoretically. Moreover, the shooting phase of the purse-seine fishing is simulated with the aim to investigate the diving behavior of the net. The flow shading effect of neighboring strands is identified as a critical parameter for the consistent predictions of the diving behavior

The Effect of Polarization and Reaction Mixture on the Rh YSZ Oxidation State During Ethylene Oxidation Studied by Near Ambient Pressure XPS

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