Titel Deelnemers "Impact of ocean waves on offshore wind farm power production" "Sara Porchetta, Nicole Van Lipzig" "The effect of wind-wave interaction on the energy harvesting of offshore wind turbines" "Sara Porchetta" "A future without renewable energy sources has become unrealistic. One of the more promising renewable energy source is wind energy, especially offshore wind energy. However, little is known about the effect of wind, waves and their interaction on the performance of wind turbines. In this PhD a numerical model will be developed that incorporates these effects and that forecasts the optimal location for offshore windfarms. This will be accomplished by coupling a microscale model with a mesoscale model for waves and wind. To obtain an accurate microscale model enough validation data are needed. Thus an experimental campaign will be performed during which wind, waves and their influence on wind turbine performance will be measured. The microscale model will be based on the WiWITS model but will include several improvements. While the microscale model can model power generation of a specific wind turbine, it needs realistic boundary conditions which will be obtained by mesoscale models. These forecast the weather at a specific location and model larger scale weather phenomena compared to microscale models. Furthermore, they will be validated using both weather balloon and satellite measurements. Mesoscale models cannot include small scale elements such as wind turbines. By coupling both models, advantages of both will be combined. Such an integrated model will predict under which wind-wave conditions wind turbines perform optimally and will help in future allocation of windfarms." "Large eddy simulations of the Martian convective boundary layer: Towards developing a new planetary boundary layer scheme" "Orkun Temel, Sara Porchetta, Tim Van Hoolst" "Evaluation of a roughness length parametrization accounting for wind-wave alignment in a coupled atmosphere-wave model" "Sara Porchetta, Orkun Temel, Jaak Monbaliu, Nicole Van Lipzig" "A New Planetary Boundary Layer Scheme Based on LES: Application to the XPIA Campaign" "Orkun Temel, Sara Porchetta" "A new roughness length parameterization accounting for wind-wave (mis)alignment" "Sara Porchetta, Orkun Temel, Jaak Monbaliu, Nicole Van Lipzig" "© Author(s) 2019. Two-way feedback occurs between offshore wind and waves. However, the influence of the waves on the wind profile remains understudied, in particular the momentum transfer between the sea surface and the atmosphere. Previous studies showed that for swell waves it is possible to have increasing wind speeds in case of aligned wind-wave directions. However, the opposite is valid for opposed wind-wave directions, where a decrease in wind velocity is observed. Up to now, this behavior has not been included in most numerical models due to the lack of an appropriate parameterization of the resulting effective roughness length. Using an extensive data set of offshore measurements in the North Sea and the Atlantic Ocean, we show that the wave roughness length affecting the wind is indeed dependent on the alignment between the wind and wave directions. Moreover, we propose a new roughness length parameterization, taking into account the dependence on alignment, consisting of an enhanced roughness length for increasing misalignment. Using this new roughness length parameterization in numerical models might facilitate a better representation of offshore wind, which is relevant to many applications including offshore wind energy and climate modeling." "RANS closures for non-neutral microscale CFD simulations sustained with inflow conditions acquired from mesoscale simulations" "Orkun Temel, Sara Porchetta, Laurent Bricteux, Jeroen van Beeck" "© 2017 Elsevier Inc. This study focuses on bridging the gap between the turbulence modelling methodologies of meterological and engineering codes by proposing a novel methodology to define the closure coefficients of Reynolds-Averaged Navier-Stokes turbulence models consistently with the physics of the atmospheric boundary layer. In this framework, different turbulence closures have been developed and tested on different full-scale test cases corresponding to different atmospheric stability conditions by performing microscale simulations with the inflow conditions provided by a numerical weather prediction (NWP) code. Developed turbulence models have been implemented into the open source computational fluid dynamics (CFD) toolbox, OpenFOAM and the inflow conditions have been acquired with another open source code, the Weather Research and Forecasting (WRF) model."