Wave energy assessments in the Black Sea

The present work aims to evaluate the wave energy resources in the Black Sea basin. The study is focused on the western part of the sea, which is traditionally considered as being more energetic. In order to give a first perspective of the wave climate, a medium-term wave analysis was carried out using in situ measured data. As a further step, a wave prediction system was implemented for the Black Sea. This was based on the simulating waves near-shore model, which is used for both wave generation and near-shore transformation. This methodology has the advantage that a single model covers the full scale of the modelling process. Various tests were performed considering data measured at three different locations. Special attention was paid to the whitecapping process, which is still widely considered to be the weak link in deep water wave modelling. Comparisons carried out against measured data show that the wave prediction system generally provides reliable results, especially in terms of significant wave heights and mean periods. By increasing the resolution in geographical space, the field distributions of wave energy were analysed for both high and average wave conditions. The analysis and the wave prediction system developed are a prerequisite for further investigations extended in time and with increased resolution in the near-shore direction.     

Modelling of wave–current interactions at the mouths of the Danube

The target of the present study is the entrance to the Danube Delta in the Black Sea. The wave conditions in this coastal sector are usually significant from an energetic point of view and the relatively strong currents induced there by the outflow from the Danube lead to interactions between waves and currents. This process modifies considerably both the magnitude and direction waves, affecting also coastal navigation and sediment transport patterns. In order to assess the effects of the wave–current interactions, the simulating waves nearshore (SWAN) model was considered for developing a multilevel wave prediction system. Validations against measured data were carried out for each computational level. Five case studies corresponding to the most relevant patterns of the environmental matrix were analyzed. Finally, in order to assess the current effect for a longer timescale, an analysis concerning the variation of the main wave parameters was performed for a 3-month period considering some reference points. The results show that the currents produce considerable changes in the wave field, especially as regards the significant wave heights, mean wave directions and wavelengths. The Benjamin–Feir index was also estimated. The analysis of the variation induced by the current over this spectral shape parameter indicates that, in certain conditions, in the target area the wave heights cannot be considered Rayleigh distributed and freak waves may also occur.