Das Projekt "Die Ausbreitung von Kfz-Emissionen in staedtischen Gebieten" wird vom Umweltbundesamt gefördert und von Universität Hamburg, Zentrum für Meeres- und Klimaforschung, Meteorologisches Institut durchgeführt. The University of Hamburg initiated a wind tunnel study of car exhaust dispersion from street canyons in an urban environment to investigate how pollution dispersion is affected by street geometry. Particular emphasis at the beginning of this work was put on the design of a line source ot represent traffic exhaust. Pollution dispersion was studied in two dimensions (i.e., infinite-length streets were assumed). The case of an isolated street canyon in open country was examined first. The same street canyon geometry was subsequently studied in an urban environment, i.e., with additional canyons of similar geometry upstream and downstream of the test street. The dynamic and dispersion characteristics of the flow in the two cases were quite different. In the canyon amidst open country we observed better canyon ventilation than in the urban roughness case.
Das Projekt "Vermeidung der durch den Strassenverkehr bedingten Verluste von Fischottern (Lutra lutra)" wird vom Umweltbundesamt gefördert und von Aktion Fischotterschutz e.V. durchgeführt. Der Strassenverkehr stellt die Todesursache Nummer 1 fuer den Fischotter dar. Diese Verluste werden sich zahlenmaessig in den naechsten Jahren noch drastisch erhoehen. Der Grund dafuer ist in dem immer noch ansteigenden Verkehrsaufkommen zu suchen. So stieg der Individualverkehr in den neuen Bundeslaendern um rund 30 Prozent. Der in dieser Entwicklung begruendete und forcierte Neu- wie Ausbau von Strassen macht das Erarbeiten von Massnahmen notwendig, welche eine Vermeidung von Otter-Verkehrsopfern ermoeglichen. Aufgabe des Vorhabens war es daher, Daten ueber die verunfallten Fischotter, die Unfallumstaende sowie die Konstellationen der Unfallorte, die das Gefaehrdungspotential ausmachen bzw. erhoehen, zu sammeln und zu analysieren. Basierend auf diesen Erhebungen, wurden erste Empfehlungen fuer moegliche Schutzmassnahmen erarbeitet, welche im Rahmen von Strassenneu- und Ausbaumassnahmen an unterschiedlichen Orten beispielhaft umgesetzt werden sollen.
Das Projekt "Konstruktion und Erprobung akustisch optimierter Fluegel von Windkraftanlagen" wird vom Umweltbundesamt gefördert und von Universität Stuttgart, Institut für Aerodynamik und Gasdynamik durchgeführt. General Information/Project Objectives: The main objectives of the project are: - To design acoustically optimized airfoils for wind turbines using all noise reducing concepts which were found to be successful (trailing-edge serrations, new airfoil shapes). - To design acoustically optimized blades and to test them in a large wind tunnel in order to include rotation and/or unsteady flow. - To improve the understanding of 'excess noise' and to develop guidelines to prevent it. - To quantify the impact of noise reducing concepts on the power output of a large wind turbine. It is expected that a rotor which is equipped with acoustically optimized blades yields a reduction in sound power level of 3-6 dB compared to a conventional state-of-the-art rotor. Technical Approach: The technical approach consists basically of two steps: (1) the design of acoustically optimized airfoils, and (2) the testing of these airfoils on a model rotor in the wind tunnel. The aerodynamic design will be accomplished using standard tools like the Eppler code or XFOIL. The acoustic evaluation will be performed by employing prediction models for the two important noise mechanisms, namely trailing-edge noise and inflow-turbulence noise. These prediction models are sensitive enough to capture the influence of the exact airfoil shape on the noise production. Since trailing-edge serrations have been proven to be an efficient means for reducing trailing-edge noise, they will be integrated in the design. The airfoils will be tested aerodynamically and acoustically in two wind tunnels at the University of Stuttgart and the National Aerospace Laboratory NLR, respectively. In a second step the airfoils will be used to design two acoustically optimized rotor blades. One blade will include trailing-edge serrations. A third blade will be designed as a reference blade based on standard airfoils like the NACA-63xx or -64xx series. The blades will be tested in a two-bladed configuration in the German-Dutch Windtunnel (DNW). Noise measurements will be performed using an inflow microphone array. Additional experiments will be undertaken in order to understand the phenomenon of 'excess noise'. As a final step, the industrial partner Rotorline will carry out a design study for a new 1 MW rotor which is based on the new airfoils. Here, the aerodynamic characteristics which were measured in the wind tunnel will be used. This study will allow to assess the impact of noise reducing concepts (serrations, new airfoil shapes) on the power output of a wind turbine. Expected Achievements: The expected achievements are: - A new airfoil family which incorporates all the state-of-the-art noise reducing concepts (serrations, new airfoil shapes) with 'best-as-possible' aerodynamic features. - A validated methodology to design 'silent' airfoils while taking the aerodynamic performance into account. - An improved understanding of the generation, modelling, and reduction of aerodynamic noise in case of rotatio
Das Projekt "Ammoniakemissionen nach der Ausbringung von Fluessigmist auf Gruenland" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Fakultät IV Agrarwissenschaften II, Institut für Agrartechnik durchgeführt. Ueber 90 Prozent Ammoniakemissionen stammen aus der Landwirtschaft, davon 40 Prozent aus der Tierhaltung, mit drei Windtunnelsystemen wird der Einfluss unterschiedlicher Applikationstechniken (Prallteller, Schleppschlauch, Schleppschuh, Injektor) und Witterungsfaktoren (Temperatur, Einstrahlung) auf die Hoehe der Ammoniakemissionen nach der Ausbringung von Fluessigmist auf Gruenland in Parallelversuchen ermittelt.