Siliciumorganische verbindungen : LIX. 1,5-Bis(trimethylsilyl)-naphthalin

The addition vs. deprotonation ratio in the reaction of nitriles with n-PrMgBr is increased by complexation of the Grignard reagent with LiClO₄. For nitriles having moderately labile α-hydrogen atoms the deprotonation reaction is almost completely suppressed; but for nitriles having very labile α-hydrogen atoms (CH₃ CN, PhCH₂CN) yields in ketones are increased from 2 to 10–20%.     

Particle-Laden Turbulent Channel Flow and Particle-Wall Interactions

The behavior of particle-laden gases in a turbulent channel flow is studied at moderate Reynolds number. Effects of the wallparticle interaction models on the velocity, statistics, and dispersion of the particles are presented. The results were obtained from a direct numerical simulation with particle feedback on the gas phase. The models were found to considerably influence the studied particle properties. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Forces acting on particles in separated wall‐bounded shear flow

Trajectories of solid particles in laminar and turbulent flow over a backward‐facing step (BFS) were numerically computed by integrating the equation of motion for particles. The various forces acting on the particles [5],[6] were calculated for a variety of flow Reynolds numbers and for different particle characteristics such as the Stokes number and the particle‐to‐fluid density ratio. The investigation was conducted for the distinct flow regimes of the BFS flow separately. Generally, the drag and gravitation were found to be the most significant forces. The lift and history force were the next most important, mostly two orders of magnitude smaller, but in some cases closing up to the other two in importance. The pressure and virtual mass effects were very small for the majority of cases. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Viscous compressible stability investigations in cylindrical coordinates

A viscous stability code based on the linearized compressible Navier‐Stokes equations in cylindrical coordinates was developed. In this contribution, we discuss general aspects of its application and present some results on the stability of swirling jet flow at high subsonic Mach number. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)