Die mittelpleistozäne Flußentwicklung im nordöstlichen Harzvorland: Petrographie, Terrassenstratigraphie

The present study deals with the evolution of the middle Pleistocene river system in the north-eastern foreland of the Harz Mtns. Sediments of the middle fluvial terrace level (early Saalian time) are the main objectives. By using these sediments supplementary with some results of upper fluvial terrace level (early Elesterian time or older) the fluvial palaeogeography within the area has been reconstructed. The sediments were investigated with respect to their gravel spectra, heavy mineral record, sedimentary structures and altitude above the recent river beds. Due to the resulting specifics the sediments have been attributed to particular rivers in the area. Furthermore it is possible to distinguish between fluvial sediments and Elsterian as well as Saalian fluvioglacial deposits. Together with discernible middle or upper terrace characteristics this led to a spatio-temporal reconstruction of the palaeo river system of the Harz Mtns. It revealed that not only during upper terrace sedimentation but even while middle terraces were deposited the rivers partly diversed. These river diversions were mainly caused by hydrodynamic changes reflecting interaction of the fluvial system with Elsterian and Saalian ice shield formation in the north. The Rivers Ecker, Ilse, Rammelsbach, Holtemme, Goldbach, Bode, Selke and Eine were affected by this development as follows: Upper terrace level formation: • The Ecker River formerly ran between its recent river bed and that of the Use River in direction to the Großer Fallstein Mtn. • The Use River flowed to the NE towards the Huy Mtn. • The Goldbach River and the Holtemme River mutually ran to the NW south of the Huy Mtn. After uniting with the Use River and Ecker River it ran south of the Großer Fallstein Mtn. Middle terrace level formation: • The Ecker River flowed far more NE. • Near to the Harz Mtns. the Use River flowed more in the E. The tributary junction of the Rammelsbach River was located far more downstream. Thereafter the Use River ran to the N between Huy Mtn. and Großer Fallstein Mtn. to end up flowing in the area of the Großes Bruch. • The Holtemme River kept its course. Its recent tributary the Goldbach River flowed to the NE and joined the Bode River after leaving the Harz Mtn. Range. • The Eine River ran to the NW when passing todays city of Aschersleben. After flowing together with the Selke River in the area of the Seeländerei it became a tributary to the Bode River. • The Bode River within the recent tributary junction of the Holtemme ran far more in the W. In the area of the Espenbruch it flowed eastwards to the Saale River. The following general implications resulted out of the study: • The so called “mixed sediments” sensu Rosenberger & Altermann (1975) have now been interpreted as proximal fluvioglacial deposits. • High altitudes of middle terrace fluvial deposits in the courses of the Ecker River and Use River were formerly assigned to post middle Pleistocene uplift of the Großer Fallstein Mtn. (Feldmann, 2002). The present study suggests that the unusual high altitudes should rather be attributed to post middle terrace level erosion of the shortened Ilse- Rammelsbach river system or fluvioglacial processes below the glacier. • Within the north-eastern foreland of the Harz Mtns. middle terrace level deposits have previously been subdivided by cryoturbation horizons or short-term progradation of Saalian glaciation. This is not supported by own results for the examined area.

Wind turbine rotor blade monitoring using digital image correlation: a comparison to aeroelastic simulations of a multi-megawatt wind turbine

Optical full-field measurement methods such as Digital Image Correlation (DIC) provide a new opportunity for measuring deformations and vibrations with high spatial and temporal resolution. However, application to full-scale wind turbines is not trivial. Elaborate preparation of the experiment is vital and sophisticated post processing of the DIC results essential. In the present study, a rotor blade of a 3.2 MW wind turbine is equipped with a random black-and-white dot pattern at four different radial positions. Two cameras are located in front of the wind turbine and the response of the rotor blade is monitored using DIC for different turbine operations. In addition, a Light Detection and Ranging (LiDAR) system is used in order to measure the wind conditions. Wind fields are created based on the LiDAR measurements and used to perform aeroelastic simulations of the wind turbine by means of advanced multibody codes. The results from the optical DIC system appear plausible when checked against common and expected results. In addition, the comparison of relative out-of-plane blade deflections shows good agreement between DIC results and aeroelastic simulations.