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Bergen, Norway

StormGeo AS was founded in 1997 and is one of the largest privately held weather service providers worldwide. It provides meteorological services, particularly to the offshore, renewable energy, shipping, corporate enterprise and media industries. It has offices in Norway, United States, Great Britain, UAE, Sweden, Azerbaijan, Brazil, Denmark, Germany and Singapore. The headquarters is located in Bergen, Norway.Through an expansion of its activities and the acquisition of MetConsultancy in 2011 and ImpactWeather in 2012 StormGeo became the number one provider of MetOcean services to the offshore oil and gas industry globally. Wikipedia.


Kalvig S.,University of Stavanger | Kalvig S.,StormGeo | Manger E.,Acona Flow Technology AS | Hjertager B.H.,University of Stavanger | Jakobsen J.B.,University of Stavanger
Energy Procedia | Year: 2014

In this paper the effect of wave influenced wind on offshore wind turbines is studied numerically.The wave is seen as a dynamical roughness that influences the wind flow and hence the wind turbine performance. An actuator line representation of the NREL's 5 MW offshore baseline wind turbine is placed in a simulation domain with a moving mesh that resolves the ocean waves. These wave influenced wind turbine simulations, WIWiTS, show that the wave will influence the wind field at the turbine rotor height. Both the produced power and the tangential forces on the rotor blades will vary according to the three different cases studied: wind aligned with a swell, wind opposing the swell and wind over a surface with low roughness (no waves). © 2014 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license. Source


Five different planetary boundary layer (PBL) schemes in the Weather Research and Forecasting (WRF) model have been tested with respect to their capability to model boundary layer parameters relevant for offshore wind deployments. For the year 2005, model simulations based on the YSU, ACM2, QNSE, MYJ and MYNN2 PBL schemes with WRF have been performed for the North Sea and validated against measurements from the FINO1 platform. In part I, the investigations had focused on the key parameters 100 m mean wind speed and wind shear in terms of the power-law exponent. In part II, the focus is now set on the capability of the model to represent height and stability of the marine atmospheric boundary layer.Considerable differences are found among the PBL schemes in predicting the PBL height. A substantial part of this variation is explained by the use of different PBL-height definitions in the schemes. The use of a standardized procedure in calculating the PBL height from common WRF output parameters, in particular the temperature gradient and the wind shear, leads to reduced differences between the different schemes and a closer correspondence with the FINO1 measurements. The study also reveals a very clear seasonal dependency of the atmospheric stability over Southern North Sea. During winter time, the marine atmospheric boundary layer is more or less neutral with several episodes of unstable periods. During spring and early summer, the occurrence of periods with very stable stratification becomes dominant with stable conditions up to 40-45% of the time when warm continental air is advected from the South. In general, the results of part II confirm again that the MYJ scheme performs slightly better than the others and can therefore be suggested as first choice for marine atmospheric boundary layer simulations without a priori information of atmospheric stability in the region of interest. Copyright © 2014 John Wiley & Sons, Ltd. Source


Five different planetary boundary layer (PBL) schemes in the weather research and forecasting model have been tested with respect to their capability to model boundary layer parameters relevant for offshore wind deployments. For the year 2005 model simulations based on the Yonsei University, asymmetric convection model version 2, quasi-normal scale elimination, Mellor-Yamada-Janjic and Mellor-Yamada-Nakanishi-Niino PBL schemes with weather research and forecasting have been performed for the North Sea and validated against measurements of the Forschungsplattformen in Nord- und Ostsee Nr.1 platform. The investigations have been focused on the key parameters 100 m mean wind speed and wind shear expressed by the power law exponent α. All PBL-schemes are doing well in reproducing averages and average annual statistics of the 100 m wind speed. However, two of the schemes (Yonsei University and Mellor-Yamada-Nakanishi-Niino) overestimate the wind speed above 15 m s-1 systematically. The results for the power law wind profile show a large variability between the models and the observations for different atmospheric stability conditions and also differ a lot from the industry standards. Overall, the Mellor-Yamada-Janjic scheme performs slightly better than the others and is suggested as first choice for marine atmospheric boundary layer simulations without apriori information of atmospheric stability in the region of interest. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd. Source


Kalvig S.,University of Stavanger | Kalvig S.,StormGeo | Manger E.,Acona Flow Technology | Hjertager B.,University of Stavanger
Journal of Physics: Conference Series | Year: 2014

The performance of a model wind turbine is simulated with three different CFD methods: actuator disk, actuator line and a fully resolved rotor. The simulations are compared with each other and with measurements from a wind tunnel experiment. The actuator disk is the least accurate and most cost-efficient, and the fully resolved rotor is the most accurate and least cost-efficient. The actuator line method is believed to lie in between the two ends of the scale. The fully resolved rotor produces superior wake velocity results compared to the actuator models. On average it also produces better results for the force predictions, although the actuator line method had a slightly better match for the design tip speed. The open source CFD tool box, OpenFOAM, was used for the actuator disk and actuator line calculations, whereas the market leading commercial CFD code, ANSYS/FLUENT, was used for the fully resolved rotor approach. © Published under licence by IOP Publishing Ltd. Source


Kalvigab S.M.,University of Stavanger | Kalvigab S.M.,StormGeo | Mangerc E.,Acona Flow Technology AS | Kverneland R.,University of Stavanger
Energy Procedia | Year: 2013

A flexible open source based CFD method is developed in order to directly study the effects of the wave movement on the wind field in a neutral stratified atmosphere. Sea surface waves modify the wind field in the marine atmospheric boundary layer (MABL) in different ways. Long periodic waves (swell) resemble a sinusoidal wave. The flow responses over this sinusoidal wave are studied in detail by the use of a moving grid approach. Waves aligned with the wind and opposed the wind are studied. Simulations show that a fast moving swell aligned with the wind will speed up the wind in the lowest meters of the MABL, whereas a fast moving swell opposed to the wind field will reduce and even revert the wind speed in the lowest meters. Swell opposing the wind field will also generate more turbulence in the lowest meters of the MABL than when waves and wind are aligned with each other. The simulations are compared with a logarithmic wind profile and wave influence causes the wave induced wind profiles to deviate from the logarithmic shape, especially in the case where swell is opposing the wind. © 2013 The Authors. Source

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