Andreas Schroeder

Low Speed Validation Tests on Engine/Airframe Integration Within the EC Project EUROLIFT II

‡In this overview the measurement techniques and results gained in the project EUROLIFT II will be presented. A realistic transport aircraft configuration was measu red with the measurement techniques force measurements, moment measurements, pressure distribution measurements, oil -flow visualization, Infra Red (IR) imaging and Particle Image Velocimetry (PIV). The results will be used now in the European Project EUROL IFT II for validation and comparison with numerical simulations.

Experimental investigation of the flow field topology for several cargo drop configurations

Various cargo drop configurations have been analyzed using stereoscopic Particle Image Velocimetry (SPIV). The PIV measurement planes were located at several positions in the wake of a generic transport aircraft model with an open ramp. The stream- and spanwise positioning of the wind tunnel model was facilitated by means of positioning mechanism of the wind tunnel facility. The first measured configuration consisted of only the wake of the transport aircraft. The cargo configurations consisted of a model of a cargo container, including a rigid parachute and a cargo with an airdrop support platform. A fixed haltering mechanism was used to keep the cargo at a fixed position behind the wind tunnel model for the PIV measurements. The resulting velocity fields (obtained at several chord wise positions) are used to discuss the flow topologies for these airdrop configurations.

Experimental and numerical investigation of a counter rotating open rotor flow field

Stereoscopic Particle Image Velocimetry (SPIV) and unsteady Reynolds-averaged Navier Stokes (uRANS) has been applied for the flow field investigation behind a counter rotating open rotor (CROR) model. Of particular interest is the validation of numerical codes as well as a dedicated recording of the phase delays to determine the phase positions of both propellers at the experimental investigation of the flow field.

Flow field investigations in the free bypass jet flow of a V2527 engine at Ground Operation using SPIV

The investigation of the flow field at the nozzle exit of a full scale aero-engine using Stereo Particle Image Velocimetry (SPIV) aims at providing important reference and validation data required for reliable modeling and prediction. Furthermore, the turbulent jet engine exhaust flow is of prominent interest for the aerodynamic and -acoustic characterization of an aircraft engine. Especially the development of the free shear-layer between fan-bypass flow and outer flow is an important source of high-frequency noise as well as of big interest for modeling the turbulence of a jet flow correctly by advanced RANS methods. The SPIV measurements have been performed at free running fan phase positions and with a large number of statistically independent samples enabling a turbulence characterization of the fan-bypass and corresponding shear layer flow based on mean- and RMS-fields of all three velocity components, POD analysis and two-point-correlation functions.

Low Speed High Lift Validation Tests within the European Project EUROLIFT II

The present paper describes the wind tunnel tests performed within the framework of the European High-Lift Project EUROLIFT II and focuses on the discussion of their results. The goal of the project is to optimize and validate numerical and theoretical methods for exact prediction of the aerodynamics of an aircraft in high-lift configuration at flight Reynolds numbers. To increase the basic understanding of complex high-lift aerodynamics and to produce comparative data for numerical design methods, wind tunnel test were executed inthe Airbus Low Speed Windtunnel (LSWT) and the European Transonic Windtunnel (ETW). During these tests, which covered low and high Reynolds number conditions, the model complexity was increased stepwise up to a fully high-lift aircraft configuration. Various measurement techniques were applied to gain the maximum of aerodynamic information. nBecause the presentation of a complete results analysis is far beyond the scope of this paper it gives an overview over the test facilities, the used test techniques and highlights selected results.

Multi-stereo PIV measurement of propeller wake flow in industrial facility

The flow in the wake of an 11-bladed propeller is investigated by means of phase-locked multi-stereo Particle Image Velocimetry. The use of multiple stereo-PIV systems and the multi-pulse acquisition strategy allow for the reduction of the measurement error and for the enhancement of the velocity dynamic range. The application of the measurement technique in the Airbus Low Speed Wind Tunnel industrial facility (LSWT, Bremen, Germany) poses challenges mainly due to the vibrations of the imaging system and acquisition phase jitter, ultimately affecting the spatial resolution of the measurement. A correction scheme based on the analysis of velocity fields from different stereo-PIV systems is used to largely compensate these effects, providing velocity fields suitable to be used for validation of computational aeroacoustics codes. Results show that a lower measurement error can be achieved when velocity fields from several stereo-PIV systems are combined. Furthermore, the correction scheme appears to reduce the signal modulation introduced by vibrations in the wake region.