Numerical simulations are presented in order to test airfoil optimization criteria from the aeroelastic point of view. Based on an Evolution Strategy, airfoil-shape point optimization has been performed as a lift constrained drag minimization at a given Mach/Reynolds number combination for transonic flow. Additional to the drag minimization, the propagation time of pressure disturbances from th...

A gradient-based Newton–Krylov algorithm is presented for the aerodynamic shape optimization of singleand multi-element airfoil configurations. The flow is governed by the compressible Navier–Stokes equations in conjunction with a one-equation transport turbulence model. The preconditioned generalized minimal residual method is applied to solve the discrete-adjoint equation, which leads to a fa...

Exhaust gases from an internal combustion engine, alternatively powered by gasoline or by liquefied petroleum gas, were analysed for polynuclear aromatic hydrocarbons. The engine operated a lift truck for the handling of warehouse goods. A combined condensation-filtration apparatus was constructed for sampling of the exhausts. The basic steps of the analytical procedure are summarized here. Sev...

We examine Weyl groups of minimal connected simple groups of finite Morley rank of degenerate type. We show that they are cyclic, and lift isomorphically to subgroups of the ambient group.

Active control of the production choke valve is the recommended solution to prevent casing-heading instability in gas-lifted oil wells. Focus of this work is to find a simple yet robust control structure for stabilization of the system. In order to find suitable control variables, a controllability analysis of the system with different candidate control variables and two alternative manipulated...

Disk galaxies in a cluster of galaxies are moving in hot gas filling the cluster. Generally, they are moving at transonic or supersonic velocities. If ram-pressure stripping is insufficient to destroy the gas disk, the galaxies should be affected by the wind of the surrounding hot gas similar to an airfoil. In this paper, I consider whether the aerodynamic interaction can be strong enough to fo...