CFD investigation of a complete floating offshore wind turbine

This chapter presents numerical computations for floating offshore wind turbines for a machine of 10-MW rated power. The rotors were computed using the Helicopter Multi-Block flow solver of the University of Glasgow that solves the Navier-Stokes equations in integral form using the arbitrary Lagrangian-Eulerian formulation for time-dependent domains with moving boundaries. Hydrodynamic loads on the support platform were computed using the Smoothed Particle Hydrodynamics method. This method is mesh-free, and represents the fluid by a set of discrete particles. The motion of the floating offshore wind turbine is computed using a Multi-Body Dynamic Model of rigid bodies and frictionless joints. Mooring cables are modelled as a set of springs and dampers. All solvers were validated separately before coupling, and the loosely coupled algorithm used is described in detail alongside the obtained results

Efficient approaches for fluid structure interaction with fully enclosed incompressible flow domains

Many popular partitioned approaches to fluid-structure interaction (FSI) problems fail to work for an interesting subset of problems if highly deformable structures are interacting with incompressible flows. This is particularly true for coupling approaches based on Dirichlet-Neumann substructuring, both for weak and strong coupling schemes. The subset is characterized by the absence of any unconstrained out flow boundary at the fluid field, that is the fluid domain is entirely enclosed by Dirichlet boundary conditions. The inflating of a balloon with prescribed in flow rate constitutes a simple problem of that kind. The commonly used coupling algorithms will not satisfy the fluid's incompressibility during the FSI iterations in such cases. That is because the structure part determines the interface displacements and the structural solver does not know about the constraint on the fluid field. To overcome this deficiency of partitioned algorithms a small augmentation is proposed that consists in introducing the fluid volume constraint on the structural system of equations. This allows to circumvent the dilemma of the fluid's incompressibility. At the same time the use of a Lagrangian multiplier to introduce the volume constraint allows to obtain the pressure level of the fluid domain. However, the customary applied relaxation of the interface displacements has to be abandoned in favor of the relaxation of coupling forces. These modifications applied to a particular strong coupled Dirichlet-Neumann partitioning scheme result in an efficient and robust approach that exhibits only little additional numerical effort. Numerical examples with largely changing volumes of the enclosed fluid show the capabilities of the proposed scheme

Multidisciplinary Design Optimization of Reusable Launch Vehicles

Reusable launch vehicles have once again become an attractive proposition, due to recent advancements in technology, and the opportunity to massively expand our accessibility to space. This paper discusses the optimization software under ongoing development at the University of Glasgow, that can be applied to such vehicles. Considering the diversity of previous and existing concepts, this work seeks to rapidly produce novel configurations using low-fidelity analysis methods. At present, surface inclination methods for high-speed aerodynamic computation are coupled with a simple six degree-of-freedom finite element beam model. The resulting aerostructural system is then utilized in a population based design optimization framework. Discussions of these methodologies are provided, along with an overall outline of their combination in a typical large design space optimization. Descriptions of the design variables employed are presented, along with an analysis of the methods utilized to constrain geometric properties and performance metrics, in order to avoid undesirable characteristics or infeasible configurations. Finally, a multi-objective aerostructural trim optimization is carried out, with comparison to a prior reusable launch vehicle concept

Standardization of the egg hatch test for the detection of benzimidazole resistance in parasitic nematodes

The ability to reliably detect anthelmintic resistance is a crucial part of resistance management. If data between countries are to be compared, the same test should give the same results in each laboratory. As the egg hatch test for benzimidazole resistance is used for both research and surveys, the ability of different laboratories to obtain similar results was studied through testing of known isolates of cyathostomins, Haemonchus contortus, Ostertagia ostertagi, and Cooperia oncophora in programs supported by the EU (Cost B16 and FP6-PARASOL). Initial results showed difficulties in obtaining reproducible and similar data within and between laboratories. A series of ring tests, i.e., simultaneous and coordinated rounds of testing of nematode isolates in different laboratories was subsequently performed. By adopting identical protocols, especially the use of deionized water and making dilutions of thiabendazole in dimethyl sulfoxide in the final ring test, laboratories correctly identified both susceptible and resistant isolates. The protocols for the test and preparation of solutions of thiabendazole are described