02 Fakultät Bau- und Umweltingenieurwissenschaften
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/3
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Item Open Access Flow field and scouring effects of steady and pulsating jets impinging on a movable bed(1979) Kobus, Helmut; Leister, Peter; Westrich, BernhardThe flow field and erosion pattern of continuous and pulsating impinging jets has been studied experimentally. The mean velocity field as well as turbulent and pulsation components, wall pressure and wall shear stress distributions were investigated in an axisymmetric air jet impinging upon a rough wall. The results show how harmonic velocity pulsations at the nozzle affect both the mean and the turbulent flow field. Corresponding erosion tests with a vertical water jet impinging upon a uniform sand bed exhibited under certain conditions a greatly enhanced erosion rate. The increase in erosion capacity due to pulsation seems to be due to both the changes in the mean flow field and to the greatly increased lateral correlation of the velocity field in the impinging region.Item Open Access Bond of ribbed bars under high cycle repeated loads(1979) Rehm, Gallus; Eligehausen, RolfTo determine the bond behavior of ribbed bars under repeated loads, 308 pullout specimens were tested. The specimens failed by pulling out of the bars. In the tests the following parameters were varied: maximum load and load amplitude, bar diameter, concrete quality, and bond Iength. Furthermore, as a comparison, tests under sustained load were carried out. A repeated load has a similar influence on the bond as on the deformation and failure behavior of unreinforced concrete, and it accelerates, in comparison with a sustained load, the nonelastic deformation (slip).Item Open Access Wassernutzung für Kühlzwecke(1979) Kobus, HelmutMehr als die Hälfte des Wasserverbrauchs in der Bundesrepublik wird für Kühlzwecke eingesetzt. Da die Kühlkapazität der Gewässer in Engpaßzeiten zur Abwärmebeseitigung nicht ausreicht, müssen Rückkühlverfahren eingesetzt werden. Ein wirtschaftlicher Einsatz der verfüigbaren Kühlverfahren unter Beachtung der Umweltbestimmungen erfordert den Einsatz von Optimierungsmodellen. Die Anwendung eines solchen Modells auf den Oberrhein illustriert, daß mit Hilfe verfeinerter Methoden beträchtliche Energiemengen zusätzlich genutzt werden können und gibt ein Werkzeug zur Quantifizierung der Auswirkungen von Umweltbestimmungen an die Hand.