Browsing by Author "Van Vledder, Gerbrant Ph."

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Long-term analysis of wave power potential in the Black Sea, based on 31-year SWAN simulations
(Elsevier, 2016-12-19) Van Vledder, Gerbrant Ph.; Akpınar, Adem; Bingölbali, Bilal; Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü.; 0000-0002-9042-6851; 0000-0003-4496-5974; ABE-8817-2020; AAC-6763-2019; AAB-4152-2020; 23026855400; 57189584264
This study analyzes the wave energy potential in the Black Sea based on long-term model simulations. A dataset covering the period of 1979-2009 is produced using a calibrated numerical wave prediction model (SWAN). This dataset was analyzed in detail to determine the wave energy potential to enable a reliable and optimal design of wave energy conversion devices in the Black Sea. This analysis provides information on the long-term variability as well as on the annual, seasonal and monthly averages. The analysis of the hindcast results is conducted on a spatial and a location scale. The spatial analysis provides information for the entire Black Sea on; the averaged mean wave energy flux over the period 1979-2009, and the decades 1980-1989, 1990-1999, and 2000-2009, seasonal and monthly averages of wave energy flux during 31 years, variability indices for the 1979-2009 period, and variabilities on monthly and seasonality basis based on inter-annual averages during 31 years. The location scale considered nine locations providing information on; wave power roses, probabilities of occurrence and cumulative distribution functions of wave power in different power ranges, variation and trend of yearly average wave power, seasonal average wave power and its annual variations, and quantities of wave energy flux for different H-m0 and Tm-10 ranges. Results show that areas with the highest wave energy potential are located in the south-western part of the Black Sea. These areas are; Burgas - Rezovo (BR) with an average annual total energy of 43.9 MW h/m followed by Dolni Chiflik - Shkorpilovtsi (DCS) with 37.3 MW h/m and Istanbul - Alacali (IA) with 36.1 MW h/m.
Modelling of wind waves in the sea of the Marmara
(Türk Deniz Araştırmaları Vakfı-Tüdav, 2016) Van Vledder, Gerbrant Ph.; Özsoy, Emin; Çağatay, M. Namık; Balkıs, Neslihan; Özturk, Bayram; Kutupoğlu, Volkan; Akpınar, Adem; Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü.; 0000-0002-9042-6851; AAC-6763-2019; AAD-6603-2021; ABE-8817-2020
Wave climate simulation for the black sea basin
(Iahr-int Assoc Hydro-environment Engineering Research, 2015-01-01) Van Vledder, Gerbrant Ph.; AKPINAR, ADEM; BİNGÖLBALİ, BİLAL; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/ İnşaat Mühendisliği Bölümü.; 0000-0002-5422-0119; 0000-0001-6314-9118; 0000-0003-4496-5974; AAC-6763-2019; AAB-4152-2020; ABE-8817-2020
This study investigates long-term variability of wave characteristic trends in the Black Sea basin over a period of 31 years. The state-of-the art spectral wave model SWAN was applied to hindcast 31-year of wave conditions. The simulation results were used to assess the inter-annual variability and long-term changes in the wave climate of the Black Sea for the period 1979 to 2009. The model was forced with Climate Forecast System Reanalysis winds, which is determined as the best wind source in Van Vledder and Akpinar (2015). To obtain accurate and reliable results the wave model SWAN was calibrated and validated against all, but limited, available measurements at offshore and near-shore locations located in different regions of the Black Sea. In the calibration process, we focus on especially white-capping and wind input parameters and recently developed formulations. Thus, for the Black Sea basin the best setting and model with the best configuration for the source terms in the wind-wave modelling is obtained. The results of the wave hindcast were also validated against satellite data to assess the spatial variability of wave model quality. From the simulation results, the seasonal and spatial variability of the mean annual significant wave height and wave energy period is obtained and discussed.
Wave model predictions in the Black Sea: Sensitivity to wind fields
(Elsevier, 2015-10) Van Vledder, Gerbrant Ph.; Akpınar, Adem; Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü.; 0000-0002-9042-6851; ABE-8817-2020; AAC-6763-2019; 23026855400
This paper evaluates the impact of using different wind field products on the performance of the third generation wave model SWAN in the Black Sea and its capability for predicting both normal and extreme wave conditions during 1996. Wind data were obtained from NCEP CFSR, NASA MERRA, JRA-25, ECMWF Operational, ECMWF ERA40, and ECMWF ERA-Interim. Wave data were obtained in 1996 at three locations in the Black Sea within the NATO TU-WAVES project. The quality of wind fields was assessed by comparing them with satellite data. These wind data were used as forcing fields for the generation of wind waves. Time series of predicted significant wave height (H-mo), mean wave period (T-m02), and mean wave direction (DIR) were compared with observations at three offshore buoys in the Black Sea and its performance was quantified in terms of statistical parameters. In addition, wave model performance in terms of significant wave height was also assessed by comparing them against satellite data. The main scope of this work is the impact of the different available wind field products on the wave hindcast performance. In addition, the sensitivity of wave model forecasts due to variations in spatial and temporal resolutions of the wind field products was investigated. Finally, the impact of using various wind field products on predicting extreme wave events was analyzed by focussing on storm peaks and on an individual storm event in October 1996. The numerical results revealed that the CFSR winds are more suitable in comparison with the others for modelling both normal and extreme events in the Black Sea. The results also show that wave model output is critically sensitive to the choice of the wind field product, such that the quality of the wind fields is reflected in the quality of the wave predictions. A finer wind spatial resolution leads to an improvement of the wave model predictions, while a finer temporal resolution in the wind fields generally does not significantly improve agreement between observed and simulated wave data.
Wind and wave characteristics in the Black Sea based on the SWAN wave model forced with the CFSR winds
(Elsevier, 2016-11-01) Van Vledder, Gerbrant Ph.; Akpınar, Adem; Bingölbalı, Bilal; Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü.; 0000-0002-9042-6851; 0000-0003-4496-5974; AAC-6763-2019; ABE-8817-2020; AAB-4152-2020; 23026855400; 57189584264
Wind and wave characteristics and their long-term variability in the Black Sea over a period of 31 years are investigated in this study. The state-of-the art spectral wave model SWAN is implemented to perform a 31 - year wave hindcast in the area of interest. The simulation results are used to assess the inter-annual variability and long-term changes in wind and wave climate in the Black Sea for the period 1979-2009. The SWAN model is forced with the Climate Forecast System Reanalysis (CFSR) winds. The model is calibrated and validated against available wave measurements at six offshore and near-shore locations spread over a large region in the Black Sea. The calibration was performed by tuning parameters in the white-capping and wind input formulations against available measurements for 1996 at three offshore locations (Gelendzhik, Hopa, and Sinop). The validation was carried out using measured data, at Gelendzhik, Hopa, and Sinop offshore locations, Gloria drilling platform and Karaburun and Filyos near-shore locations. From the 31-year simulation results, the long-term spatial distributions and changes of the mean wind and mean and maximum wave characteristics and their inter-annual variabilities were determined. The calibration improved SWAN model performance by 11.6% for H-m0 and 3.3% for T-m02 on average at three locations. The mean annual significant wave height (H-m0) and mean wind speed (WS) indicate the occurrence of higher wave heights and wind speeds in the western Black Sea compared to the south eastern coasts of the Black Sea. The coefficient of variation over the Black Sea for H-m0 and WS shows that the variability for H-m0 is higher than that of WS. It is also observed that the variability for H-m0 is higher in areas (such as offshore Gelendzhik, Russia) where the variability of WS is high. Besides, the storms mentioned in the previous studies (such as Galabov and Kortcheva, 2013; Tarakcioglu et al., 2015) are observed in four interesting characteristic areas with maximum H-m0 determined in this study over the Black Sea.