Wake Vortex Flight Testing in Recent EU Research Programs

Arun K. Karwal, National Aerospace Laboratory, NLR, Amsterdam, The Netherlands

Abstract

Predominantly driven by the need to increase airport capacity, but punctuated by the topical discussion on adequate separation criteria behind larger aircraft such as the An225, A380 and the future B747-800, several European research programs have been launched aimed at expanding the knowledge of wake vortices and their effect on the overall safety level of the air transport system. These programs are designated by telltale acronyms such as MFLAME, C-WAKE, WakeNet, S-WAKE, I-WAKE, ATC-WAKE, WAKEOP, AWIATOR, CREDOS and FAR-WAKE. In these programs different experimental techniques (such as the use of windtunnel, watertank, ground lidar and catapult facilities, CFD computations, piloted simulations and flight trials) are applied as tools to investigate vortex characteristics, to determine the effects of active or passive wake vortex control (alleviation) devices and to assess the impact on flight safety of a wake encounter. A few of these research programs (notably SWAKE, I-WAKE, and AWIATOR) included actual flight tests to determine the correlation between the mentioned techniques with full-scale results and to get measurements that are difficult to obtain in a laboratory environment. NLR aircraft have participated in these programs, the paper will discuss practical issues related to aircraft instrumentation, test preparation and execution and some results of the flight test programs that were performed. Upcoming developments in the field of wake vortex flight testing are addresses as well.