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Porous materials have been widely investigated as a mean for noise reduction. Numerical simulations can be used to investigate the physical mechanisms responsible for noise reduction; however, a correct modeling of the porous medium through an equivalent fluid model is essential to minimize the computational costs. This paper reports a detailed review of a few applications of the equivalent fluid model based on a three-layer approach, a method that is particularly useful to account for the variation of porous material thickness in aerospace applications. The multilayer approach has been applied in three relevant aerodynamic noise issues: leading-edge impingement noise, turbulent boundary-layer trailing-edge noise, and jet installation noise. Comparison with experiments is used to validate the simulation approach., Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Wind Energy

Porous materials have been widely investigated as a mean for noise reduction. Numerical simulations can be used to investigate the physical mechanisms responsible for noise reduction; however, a correct modeling of the porous medium through an equivalent fluid model is essential to minimize the computational costs. This paper reports a detailed review of a few applications of the equivalent fluid model based on a three-layer approach, a method that is particularly useful to account for the variation of porous material thickness in aerospace applications. The multilayer approach has been applied in three relevant aerodynamic noise issues: leading-edge impingement noise, turbulent boundary-layer trailing-edge noise, and jet installation noise. Comparison with experiments is used to validate the simulation approach., Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Wind Energy

Магістерська дисертація складається з пояснювальної записки та графічної частини. Пояснювальна записка виконана на 126 сторінці формату А4, яка включає в себе 34 рисунків, 16 таблиць, 17 джерел використаної літератури. Графічна частина містить 9 аркушів технічних креслень форматом А1. В дисертації розглянуто основні теплові характеристики силового кабелю та вплив навколишнього середовища на процеси його нагрівання і охолодження. Проведено моделювання деталізованих і спрощених термічних моделей в програмі SolidWorks та вибір моделі для детального дослідження прокладання кабелю в різних середовищах., Master’s thesis consists of an explanatory note and graphical part. The explanatory note is made up of 126 pages of A4 format; it includes 34 figures, 16 tables, 17 references. The graphical part contains 9 sheets of A1 format technical drawings. The dissertation considers the main thermal characteristics of the power cable and the influence of the environment on the processes of its heating and cooling. Modeling of detailed and simplified thermal models in the SolidWorks program and the selection of a model for detailed investigation of cable laying in various environments have been carried out. THERMAL MODELS, SIMPLIFIED MODELS, DETAILED MODELS, THERMAL STOCK CHART, MULTILAYER MODEL

We present here numerical modelling of granular flows with the rheology in confined channels. The contribution is twofold: (i) a model to approximate the Navier–Stokes equations with the rheology through an asymptotic analysis; under the hypothesis of a one-dimensional flow, this model takes into account side walls friction; (ii) a multilayer discretization following Fernández-Nieto et al. (2016) [20]. In this new numerical scheme, we propose an appropriate treatment of the rheological terms through a hydrostatic reconstruction which allows this scheme to be well-balanced and therefore to deal with dry areas. Based on academic tests, we first evaluate the influence of the width of the channel on the normal profiles of the downslope velocity thanks to the multilayer approach that is intrinsically able to describe changes from Bagnold to S-shaped (and vice versa) velocity profiles. We also check the well-balanced property of the proposed numerical scheme. We show that approximating side walls friction using single-layer models may lead to strong errors. Secondly, we compare the numerical results with experimental data on granular collapses. We show that the proposed scheme allows us to qualitatively reproduce the deposit in the case of a rigid bed (i.e. dry area) and that the error made by replacing the dry area by a small layer of material may be large if this layer is not thin enough. The proposed model is also able to reproduce the time evolution of the free surface and of the flow/no-flow interface. In addition, it reproduces the effect of erosion for granular flows over initially static material lying on the bed. This is possible when using a variable friction coefficient but not with a constant friction coefficient.