Browsing by Author "Santoni-Ortiz, Christian"
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Item Coupling of Mesoscale Weather Research and Forecasting Model to a High Fidelity Large Eddy Simulation(Institute of Physics Publishing) Santoni-Ortiz, Christian; Garcia-Cartagena, Edgardo Javier; Ciri, Umberto; Iungo, Giacomo V.; Leonardi, Stefano; 0000-0002-0990-8133 (Iungo, GV); 0000-0002-9809-7191 (Leonardi, S); Santoni-Ortiz, Christian; Garcia-Cartagena, Edgardo Javier; Ciri, Umberto; Iungo, Giacomo V.; Leonardi, StefanoNumerical simulations of the flow in a wind farm in north Texas have been performed with WRF (Weather Research and Forecasting model) and our in-house LES code. Five nested domains are solved with WRF to model the meso-scale variability while retaining a resolution of 50 meters in the wind farm region. The computational domain of our in-house LES code is nested into the inner most domain of the WRF simulation from where we get the inlet boundary conditions. The outlet boundary conditions are radiative and at this stage the coupling between the two codes is one-way. The turbines in WRF are mimicked using a modified Fitch approach, while in our in-house LES we have used a rotating actuator disk combined with immersed boundaries for tower and nacelle. Numerical results agree well with meteorological data from the met tower. The power production obtained numerically on each turbine compares well with SCADA data with an index of agreement ranging between 80% to 90%. The power production from the numerical results of our in-house LES code is slightly closer to SCADA data than that of WRF.Item Data-Driven Reduced Order Model for Prediction of Wind Turbine Wakes(Institute of Physics Publishing) Iungo, Giacomo V.; Santoni-Ortiz, Christian; Abkar, M.; Porté-Agel, F.; Rotea, Mario A.; Leonardi, Stefano; Iungo, Giacomo V.; Santoni-Ortiz, Christian.; Rotea, Mario A.; Leonardi, StefanoIn this paper a new paradigm for prediction of wind turbine wakes is proposed, which is based on a reduced order model (ROM) embedded in a Kalman filter. The ROM is evaluated by means of dynamic mode decomposition performed on high fidelity LES numerical simulations of wind turbines operating under different operational regimes. The ROM enables to capture the main physical processes underpinning the downstream evolution and dynamics of wind turbine wakes. The ROM is then embedded within a Kalman filter in order to produce a time-marching algorithm for prediction of wind turbine wake flows. This data-driven algorithm enables data assimilation of new measurements simultaneously to the wake prediction, which leads to an improved accuracy and a dynamic update of the ROM in presence of emerging coherent wake dynamics observed from new available data. Thanks to its low computational cost, this numerical tool is particularly suitable for real-time applications, control and optimization of large wind farms.Item Wind Farm Modeling: From the Meso-Scale to the Micro-Scale(2018-08) Santoni-Ortiz, Christian; 0000-0002-7578-2161 (Santoni-Ortiz, C); Leonardi, StefanoThis dissertation is focused on numerical modeling of wind turbines. An initial set of simulations is performed to assess the effect of the tower and nacelle on the wake of a wind turbine. The wind turbine is modeled using the Actuator Line Model for the rotor and the Immersed Boundary Method for the tower and nacelle. Results are compared with the experimental measurements made at NTNU (Norwegian University of Science and Technology), and numerical simulations available in the literature. For the first time, we show that the tower and nacelle not only produce a velocity deficit in the wake but also affect the entrainment of mean kinetic energy. The wake of the tower interacts with that generated by the turbine blades, promoting the breakdown of the tip vortex and increasing the mean kinetic energy flux into the wake. Additionally, we studied the effect of topography on the performance and wake of a wind turbine. The topography consists of wavy ridges that are perpendicular to the flow direction. The effect of the relative position of the rotor and terrain geometry is assessed by placing the turbine either at the crest or trough of the undulating wall. To study wind turbines under realistic conditions, one-way nested mesoscale to microscale simulations of an on-shore wind farm have been performed using the Weather Research and Forecasting (WRF) model. Each simulation contains five nested domains modeling the mesoscale wind field using the planetary boundary layer scheme on the entire north Texas Panhandle region to microscale wind fluctuations and turbine wakes of a wind farm with Large-Eddy simulation (LES). Moreover, an additional nesting with our in-house LES code is performed. Numerical results agree well with meteorological, LiDAR and SCADA data. Power production and momentum deficit obtained with our in-house LES code and actuator disk model presented a better agreement than WRF because the simulation captures the wind shear on the rotor.