No description available.

No description available.

No description available.

This thesis describes an investigation into the effect of fluid and flow parameters on cavitation dynamics and cavitation erosion. A rotating disc test apparatus was developed fo: dow-type cavitation studies. A vibratory test device was also developed to study the role of cathodic and anodic potentials applied to cavitating bodies. Some major results are given below. Erosion "peaksat about 50°C in water, but under certain conditions material degradation caused by increased corrosion rate cancels out thermodynamic effects at higher temperatures. An erosion peak is also observed as a function of static pressure. Damage increases with velocity until cavitation is fully developed, at which stage the influence of velocity becomes negligible. The changes in erosion zone geometry and mass loss caused by temperature, velocity and pressure variations may be correlated with the effect these parameters have on the cavitation pressure profile. Efforts are described to develop a system for measuring this profile in the rotating disc device. Water quality including dissolved ions, as well as solid and gas impurities, influences both cavitation inception and the amount of cavitation damage caused. The synergism between cavitation erosion and corrosion causes high damage rates in corrosive, cavitating liquids. Solid impurities at medium concentrations may enhance or retard cavitation damage substantially, depending on the physical properties of the solid. Below the saturation level, increasing concentration of dissolved air in water results in a slight decrease in damage, but damage can be almost completely eliminated by the release of air bubbles into the cavitation region. Another important result is that the gas developed by the application of external potentials to a cavitating body provides protection against cavitation erosion through a gas cushioning mechanism. Cathodic protection of cavitating bodies will thus serve to decrease damage rates even in the case of corrosion-resistant materials like stainless / GR 2016

Abstract not available

The thesis continues with the bachelor thesis which had dealt with preparation bases for simulation draining and carrying materials in SWAT model. Simulation should have been realized within basin of the Jenín stream, which watershed is 4,65 km2 large. SWAT model is primary developed for the larger watersheds where simulated values doesn't attain tolerances. Because of this is thesis focused on the methodic of simulation itself, discussion of the problem when is SWAT model almost useless for the small watersheds and presentation of the calibrated values which had served as basis for verification.