标题：CONTRIBUTIONS TO THE STUDY OF WAVE ACTION ON THE HETEROGENEOUS MARINE MOBILE BOTTOM ON THE ROMANIAN SEASIDE COSTAL AREA ASSOCIATED TO THE DANUBE DELTA
摘要：The Romanian seaside related to the Danube Delta is the result of sedimentation and alluvial processes of fluvial deposits at the mouth of the Danube flowing through its three channels in the Black Sea. It is well-known that the total amount of sediment which supplies the Romanian coast, approximately 7.34% (A.Spataru), is coarse silt composed of fine sands. Research and studies have been conducted on the distribution of marine silt along the seaside belt by NIMH Bucharest, showing that near shore coastal seabed area is mainly occupied by particles with a mostly larger diameter than 0.050 mm to 0.200 mm. Size sorting of marine silt on seabed in the coastal area of the Romanian seaside north of Midia Cape is naturally processed due to wave action and marine currents. In the last period of time due to the Black Sea level fluctuations, particularly shown through Black Sea level rise superimposed with the action of the waves, the Romanian seaside near the Danube Delta is permanently under a complex and continuous process of erosion. The present research attempts to determine what diametres sand particles should have on the mobile bottom of the Romanian seaside related to Danube Delta, which may constitute a stable bed for coastal wave action. Depending on the size of sand particles and the flow regime in the coastal zone, marine erosion occurs. In this work it was considered that for the two types of sand A and B, the fluid movement in the coastal zone is in laminar field, the sizes of movement results from Froude and Reznolds references. In times of storm at the wave elevation in the coastal zone, lower costal coordinates as the one related to the hidrotehnical system of Razelm - Sinoe, are outweighed by high waves which involve the majority of particles, creating gaps (closure )in the seaside belt section determining water saturation in the hidrotehnical system Razim - Sinoe. The hidrotehnical system Razelm - Sinoe is a freshwater ecosystem that has many functions, the most important being that of water transiting from St. George brace into the Black Sea and to irrigate about 120,000 ha located in Dobrogea plateau in Constanta and Tulcea counties (N.Petrescu, 1998) .
