Browsing by Author "Markofsky, Mark"

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    Gesetzmässigkeiten der Modelldarstellung von Anlagen zur Sauerstoffanreicherung : Abschlußbericht zum Forschungsvorhaben DFG Ko 528/1 und 3 ; Bearbeitungszeitraum: 1975 - 1979
    (1979) Kobus, Helmut; Markofsky, Mark
    Der vorliegende Bericht faßt abschließend die Arbeiten des Forschungsprojekts Ko 528/1 und 3 zusammen. Das durchgeführte Arbeitsprogramm enthält folgende Abschnitte: (1) Modellgesetzmäßigkeiten der Wehrbelüftung: Dimensionsanalyse und Auswertung aller verfügbaren Modell- und Naturmeßdaten aus der Literatur. (2) Luftblasenschleier in strömendem Wasser: Systematische Laborversuche zur künstlichen Sauerstoffanreicherung in Fließgewässern unter Verwendung von Druckluft und Sauerstoffgas, sowie Auswertung der verfügbaren Literaturdaten über Labor- und Naturmessungen. (3) Luftblasenschleier in stehenden Gewässern: Systematische Labormessungen an einer Modellfamilie unterschiedlicher Dimensionen.
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    On the modelling of artificial reoxygenation
    (1977) Markofsky, Mark; Kobus, Helmut
    The results of laboratory studies on the efficiency of oxygen transfer from two dimensional bubble curtains produced by passing compressed air through a porous filter (mean diameter 180μ) and a perforated diffusor pipe (1 mm diameter ports) are presented. Comparisons with other laboratory and field data as well as with on approximate theory for oxygen transfer are made. Surface effects are found to play an important role in the present experiments tending to increase the overall apparent oxygen transfer efficiency.
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    Unified presentation of weir-aeration data
    (1978) Markofsky, Mark; Kobus, Helmut
    The literature on reoxygenation studies on free overall weirs has been reviewed with the main objective of investigating model scale effects. A nomogram has been presented for constant values of (r - 1) as a function of the nappe Froude and Reynolds numbers. Analysis of the nomogram indicates that small-scale Froude model studies tend to underestimate prototype reoxygenation, whereas laboratory experiments at prototype heights of fall tend to overestimate the reoxygenation if no consideration of flow rate is made. Correction factors for temperature and water quality effects have been examined. It is hoped that this nomogram will serve as a guide to the complicated interrelationships involved in the reoxygenation process and as a method for uniform presentation for comparison of data acquired in the future.