<p><strong>Abstract.</strong> Precise models of the impact of explosions in urban environments provide novel and valuable information in disaster management for developing precautionary, preventive and mitigating measures. Yet to date, no methods enabling accurate predictions of the process and effect of detonations at particular locations exist. We propose a novel approach mitigating this gap by combining state-of-the-art methods from photogrammetric 3D reconstruction, semantic segmentation and computational based numerical simulations. In a first step, we create an accurate urban 3D reconstruction from georeferenced aerial images. The resulting city model is then enriched with semantic information obtained from the original source images as well as from registered terrestrial images using deep neural networks. This allows for an efficient automatic preparation of a 3D model suitable for the use as a geometry for the numerical investigations. Using this approach, we are able to provide recent and precise models of an area of interest in an automated fashion. Within the model, we are now able to define the explosive charge size and location and simulate the resulting blast wave propagation using CFD simulation. This provides a full estimation for the expected pressure propagation of a defined charge size. From these results, arising damages and their extent, as well as possible access routes or countermeasures, can be estimated. Using georeferenced sources allows for the integration and utilization of simulation results into existing geoinformation systems of disaster management units, providing novel inputs for training, preparation and prevention. We demonstrate our proposed approach by evaluating expected glass breakage and expected damages impairing the structural integrity of buildings depending on the charge size using a 3D reconstruction from aerial images of an area in the inner city of Graz, Austria.</p>

The present work gives a closer insight into the aerodynamic parameters obtained for turbine exit guide vanes (TEGV) of a low pressure turbine (LPT) with riblets applied on their suction side. Experimental data was obtained by using an aerodynamic five-hole-probe including a thermocouple as well as a trailing edge probe. Additionally, a comparison between the flow fields of the experimental data and the numerical results, obtained by performing a steady state Reynolds-Averaged Navier-Stokes (RANS) simulation, was done. The investigated flow fields are located up-and downstream of the TEGV's and show a good overall agreement. Additionally, aeroelastic investigations show an influence of the changed surface structure onto the vibrations of the upstream located rotor blades. For a visual examination of the flow field, oil flow visualizations are performed and compared with results obtained by CFD simulations.

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This work presents the results of numerical investigations conducted within the framework of a project focused on studying the influence of combustor hot streaks onto the aerodynamic performance of a TCF representative geometry. Different circumferential positions of the hot streaks, in respect to the leading edges of the high pressure turbine (HPT) stator vanes, were examined in order to determine changes in the flow field and its influence on the downstream components. Numerical investigations were carried out at Bionic Surface Technologies GmbH using the commercial tool ANSYS CFX. Transient simulations were performed to obtain the flow-field and capture the propagation of the hot streaks through the HPT stage into the TCF. Time averaged five-hole-probe measurements, taken from the TU Graz transonic test turbine facility (TTTF), were used as the initial boundary conditions for the simulations. Results are showing that the circumferential position of the hot streaks influences the temperature distribution at the TCF outlet since the hot streaks follow the fluid migration in the TCF, and are therefore affected by secondary flow structures originating from the fluid interaction with the HPT and TCF struts. Results also present an increase of pressure loss below 1%, for the hot streaks simulations.

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