APPROXIMATION OF THE BOUNDARY CONDITIONS AT THE COMPUTATION OF FLOOD WAVES

The computation of wave phenomena belongs to the subject of the unsteady flow problems. To the computations boundary conditions are required. The initial conditions, usually, can be very easily produced. Generally, the upstream boundary condition is given, and this presents the actual wave for the effected and calculated lower river stretch. It is a general and difficult problem to produce the downstream boundary condition - especially for shorter river stretches - which is often substituted by the normal (steady flow) discharge curve: Q0=Q0(h). This approach - depending on the type of the flood wave - is very often not precise enough. The goal of this study is to justify that the downstream boundary condition, instead of the Q0=Q0(h) discharge curve, can be substituted by the Q=Q(h) loop, which is also a rating curve, but for unsteady flow. The computational results justified the statements of the authors. It was also numerically justified, that during a total wave flow the maximum time order of the main hydraulic parameters is: Smax, vmax, hmax (or Zmax) and Qmax

Debrecen szülötte, egyetemünk diákja és tanára, a 20. század kiemelkedő geológusa

Native of Debrecen, Student and Professor of our University, Significant Geologist of the 20th Century: Dr. Vilma Fux Székyné (1916–2006). Dr. Vilma Széky-Fux, an exceptional scientist of the 20th century, geologist and professor with Széchenyi Prize was born in Debrecen 100 years ago and passed away in Budapest 10 years ago. She carried out successful education and research at two universities contributing to geology and expert training with useful inventions and valuable works at a time of war and regimechanges. She was member of numerous national and several international scientific boards and her results were recognised abroad as well. She worked hard in aspiring student research and refereeing the results of colleagues working for scientific degrees. Her activity as an organizer, presenter and leader in the Hungarian Geological Society was outstanding. Her work was always highly respected as reflected by her prizes. The life and works of Professor Széky-Fux should stand as an example for all of us

Origin of red clays around Miskolc (North Hungary)

During the geological mapping of the northern foreland of the Biikk Mountains red clay occurrences were identified by the Department of Mineralogy and Geology, University of Debrecen. Red clays are underlain by Triassic limestone and Miocene, mainly Sarmatian siliciclastic sediments containing tuffaceous bentonites. Based on the sedimentological (grain-size distribution), mineralogical (micromineralogy, X-ray diffraction, thermal analysis) and major element geochemical (ICP-OES) examinations, it can be established that the studied red clays belong to the less weathered, so-called „reddish clay" type. Montmorillonite prevails among clay minerals, while kaolinite is subordinate. Considering the strong sedimentological and mineralogical similarity with the underlying Miocene sediments, the red clays were probably originated by the weathering of the Miocene sediments under a moderately warm and dry climate. Taking lithostratigraphic features into account, the examined red clays can be classified as members of the Pliocene-Pleistocene Tengelic or Kerecsend Red Clay Formation