A Practical Approach in the CFD Simulation of Off-shore Wind Farms through the Actuator Disc Technique

Abstract In this work a practical approach to Computational Fluid Dynamics (CFD) simulations in wind resource evaluation is proposed in a test case of the IEA project (task 31) "Wakebench" focused on the benchmarking of wind wakes models. The proposed method uses an easy wake model, the Actuator Disc (AD), in a CFD approach, in order to understand the wind behavior in a complex wind farm of 18 turbines sited in the northern part of Netherlands, with a sustainable computational load. In order to optimize the simulation results a useful tool that automates the parameters evolution was developed; such tool is able to improve the control of the engineering parameters and is useful to prepare advanced post processing. The study was mainly focused on the analysis of the single wake; also simulations on the double wake case and other tests on larger wind farm were performed with success using the same automatic approach. Results are in quite good agreement with experimental data and the differences between the predicted and experimental results are to be addressed to: global effect of stability, turbine inferences in the actual wind farm and to some lacks in physical wake model

Investigation of the Dominant Microbiota in Ready-to-Eat Grasshoppers and Mealworms and Quantification of Carbapenem Resistance Genes by qPCR

In this study, 30 samples of processed edible mealworms (Tenebrio molitor L.) and 30 samples of grasshoppers (Locusta migratoria migratorioides) were obtained from producers located in Europe (Belgium and the Netherlands) and Asia (Thailand) and subjected to PCR-DGGE analyses. The PCR-DGGE analyses showed that species in the genus Staphylococcus were predominant in the samples of mealworms from Belgium and grasshoppers from the Netherlands; species in the genus Bacillus were detected in the samples of mealworms and grasshoppers from Thailand. Moreover, Weissella cibaria/confusa/spp. was found in grasshoppers from Belgium. Since data concerning the role of novel foods such as edible insects in the dissemination of carbapenem resistance are currently lacking, the quantification of five carbapenemase encoding genes (blaNDM−1, blaVIM, blaGES, blaOXA−48, and blaKPC) by qPCR was also carried out in all the samples under study. The genes coding for GES and KPC were not detected in the analyzed samples. A very low frequency of blaOXA−48 (3%) and blaNDM−1 (10%) genes was detected among mealworms. In contrast, grasshoppers were characterized by a high incidence of the genes for OXA-48 and NDM-1, accounting for 57 and 27% of the overall grasshopper samples, respectively. The blaVIM gene was detected exclusively in two grasshopper samples from Thailand, showing only 7% positivity. The analysis of variance showed that all the effects (producers, species, and producers × species) were statistically significant for blaNDM−1, whereas for blaOXA−48 and blaVIM, no significant effects were detected for the same source of variation. Further studies are necessary to assess the possible role of edible insects as reservoirs for the resistance to carbapenems and to understand the correlation with the insect microbiota. Furthermore, an intensified surveillance plan examining the occurrence of carbapenemase encoding genes in the food chain and in environmental compartments is needed for a proper risk assessment. In such a context, the appropriate use of antimicrobials represents the main preventive action that should always be applied

Lidars for Wind Tunnels - an IRPWind Joint Experiment Project

Measurement campaigns with continuous-wave Doppler Lidars (Light detection and ranging) developed at DTU Wind Energy in Denmark were performed in two very different wind tunnels. Firstly, a measurement campaign in a small icing wind tunnel chamber at VTT in Finland was performed with high frequency measurements for increasing the understanding of the effect of in-cloud icing conditions on Lidar signal dynamics. Secondly, a measurement campaign in the relatively large boundary-layer wind tunnel at NTNU in Norway was performed in the wake of a scaled test turbine in the same configuration as previously used in blind test comparisons for wind turbine wake modelers. These Lidar measurement activities constitute the Joint Experiment Project” L4WT - Lidars for Wind Tunnels, with applications to wakes and atmospheric icing in a prospective Nordic Network” with the aim of gaining and sharing knowledge about possibilities and limitations with lidar instrumentation in wind tunnels, which was funded by the IRPWind project within the community of the European Energy Research Alliance (EERA) Joint Programme on Wind Energy