So far, wind energy has not played a major role in the group of technologies for embedded generation in the built environment. However, the wind flow around conventional tall buildings generates differential pressures, which may cause an enhanced mass flow through a building-integrated turbine. As a first step, a prototype of a small-scale ducted wind turbine has been developed and tested, which seems to be feasible for integration into the leading roof edge of such a building. Here an experimental and numerical investigation of the flow through building-integrated ducting is presented. Pressure and wind speed measurements have been carried out on a wind tunnel model at different angles of incident wind, and different duct configurations have been tested. It was confirmed that wind speeds up to 30% higher than in the approaching freestream may be induced in the duct, and good performance was obtained for angles of incident wind up to ±60°. The experimental work proceeded in parallel with computational fluid dynamics (CFD) modelling. The geometry of the system was difficult to represent to the required level of accuracy, and modelling was restricted to a few simple cases, for which the flow field in the building-integrated duct was compared with experimental results. Generally good agreement was obtained, indicating that CFD techniques could play a major role in the design process. Predicted power of the proposed device suggests that it will compare favourably with conventional small wind turbines and photovoltaics in an urban environment

-Some limitations of the classical Wall-Function approach for the near-wall boundary layer treatment in LES and URANS are presented for isothermal oscillating and pulsating channel flows. Despite their simple geometry, pulsating and oscillating flows are interesting unsteady flow test cases representative of many industrial components. A special attention will be focused on the unsteady wallshear stress prediction since it is also an indirect measure of the unsteady wall-heat transfer. A correct evaluation of the unsteady wall heat transfer is in fact critical, for example, in combustion chamber applications when flow unsteadiness due to flame instability occurs and in general in each unsteady flow situation where thermo-acoustic phenomena play an important role.

Experimental and numerical work has been carried out to determine the wall heat load at the liner structure of a model gas turbine combustion chamber. Measured cross-sectional profiles of the velocity and temperature field inside the chamber could be used to validate various CFD calculations of the combustion flow. It turned out that only a special treatment of the thermal boundary conditions at all liner walls would actually lead to appropriate values of the wall heat flux. Radiation modeling included two radiative properties models (SG single gray gas and WSSG weighted sum of gray gases) and three radiation transport models (P1, DT discrete transfer, MC Monte Carlo). The performance of the WSGG model has been assessed with charts and the impact of the radiation on the liner wall temperature distribution has been studied. The experimental values are matched within 3% deviation with the best combination of transport and radiation property models. The radiation contributes to 20-30% of the total wall heat flux. The present approach enables Siemens PG to access the thermal design of combustors more precisely.

Friction induced vibrations such as brake squealing, or juddering are still challenging topics in product engineering processes. So far, this topic was particularly relevant for the automobile industry because they were the main market for disc brake systems. However, since mobility habits change, disc brake system are more often to be found on bikes or e-scooters. In all of these systems, vibrations are excited in contacts on the micro scale but affect the user comfort and safety on the macro scale. Therefore, the aim of this cross-scale method is to analyze a system on a micro scale and to transfer the excitation mechanisms on a macro scale system. To address both scales, the current work presents a finite element model on the micro scale for the determination of the coefficient of friction, which is transferred to the macro scale and used in a multi-body simulation. Finally, a finite element modal analysis is conducted, which allowed us to evaluate the brake system behavior on base of an excitation.