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Item type:Publication, Access status: with files , Analysis of coupling techniques for overset-grid finite-volume methods(2019-09); Coupling of unstructured, overlapping 3D grids in finite-volume methods (FVM) is usually based on a local interpolation of field values, which (a) is insufficient to guarantee mass conservation and (b) requires a sufficient overlap of the wetted domain. Effects of the non-conservative coupling are analysed and the mass-dependent pressure in incompressible FVM is stabilised by global mass conservation practices. Areas with an insufficient overlap are numerically manipulated to allow the simulation of dynamic body contact. This enhanced approach is validated and applied, e.g. within the simulation of a gear pump and for contact simulations of a cylinder/sphere with a wall. The latter reveal a significant increase and a coupling of additional resistance and inertia forces.Publicationtype: Doctoral Thesis513 692 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Adjoint Navier-Stokes methods for hydrodynamic shape optimisation(2012); To efficiently calculate the sensitivity derivative of hydrodynamic objective functionals with respect to the shape, the adjoint Navier-Stokes equations were derived analytically. Consistent adjoint discretisation schemes were developed term-wise from the primal finite-volume discretisation. The adjoint method, implemented in the framework of a general-purpose pressure-correction based RANS code for unstructured grids, was validated against analytical solutions and verified by means of the direct-differentiation method. The adjoint-based sensitivity derivative was computed to guide a manual re-design of a ship hull to improve the wake field. Moreover, automatic shape-optimisation runs were carried out to reduce the power loss for ducted flows.Publicationtype: Doctoral Thesis1192 4679