Sinusoidal-gust generation with a pitching and plunging airfoil

The generation of uniform, periodic gust disturbances in an experimental context is demonstrated using a single oscillating airfoil. A pitching and heaving symmetric airfoil is suggested as a simpler alternative to existing gust-generation methods. The Theodorsen theory of unsteady aerodynamics is used as an analytical tool to dictate the kinematics necessary to produce well-defined sinusoidal gusts downstream of the airfoil. These analytic predictions improve the symmetry of fluctuations in the vertical velocity induced by the airfoil, as well as minimize the influence of vorticity shed by the oscillating airfoil. The apparatus is shown to produce smooth, repeatable gusts with high amplitudes and reduced frequencies compared to other gust-generation mechanisms in the literature. Furthermore, the control of downstream flow properties by airfoil motion kinematics has applications in experimental aerodynamics, the design of rotorcraft and light aerial vehicles, and biological propulsion.Comment: Under revie

Prospective job analysis for the next pilot generation

To accomodate the expected growth of air traffic over the next two decades new operational concepts are currently under development, which will affect to some extent the job tasks and responsibilities of pilots and air traffic controllers. How will the operators perform in their potential new roles? Can we presume that they will easily be re‐trainable? Or will the job profile change to such an extent that it has to be considered already during the selection of the most suitable candidates? Especially for ab‐initio pilot and controller candidates selection decisions imply predictions of human performance for a longterm future. Therefore, a prospective analysis of job requirements is necessary to make sure that the selection battery is aligned with future roles and tasks. DLR has developed a simulation platform called AviaSim, which allows for low‐fidelity human‐in‐the‐loop simulations of potential future job tasks for pilots and controllers. Future scenarios are based on reviews of NextGen and SESAR concept papers and as well on “future workshops” with present job holders. In AviaSim we can examine the behavior of air traffic controllers working together in one scenario with up to eight pilots and additional experimental traffic. With eye‐gaze measurement, questionnaires and cognitive task interviews performance was analyzed in one en‐route and an arrival scenario. According to preliminarily findings future operators will need a higher degree of competence for operational monitoring, distributed teamwork, and time‐based operations. The simulation platform and the experimental setups are discussed in the paper

Leading edge vortex formation and detachment on a flat plate undergoing simultaneous pitching and plunging motion: Experimental and computational study

This study focuses on the formation and detachment of a leading edge vortex (LEV) appearing on an airfoil when its effective angle of attack is dynamically changed, inducing additional forces and moments on the airfoil. Experimental measurements of the time-resolved velocity field using Particle Image Velocimetry (PIV) are complemented by a computational study using an URANS (Unsteady Reynolds-Averaged Navier–Stokes) framework. In this framework a transition-sensitive Reynolds-stress model of turbulence, proposed by Maduta et al. (2018), which combines the near-wall Reynolds-Stress model by Jakirlic and Maduta (2015) and a phenomenological transition model governing the pre-turbulent kinetic energy by Walters and Cokljat (2008), is employed. Combined pitching and plunging kinematics of the investigated flat plate airfoil enable the effective inflow angle to be arbitrarily prescribed. A qualitative assessment of flow fields and a quantitative comparison of LEV characteristics in terms of its center position and circulation as well as an investigation of the mechanism causing the vortex to stop accumulating circulation revealed close agreement between the experimental and simulation results. Further considerations of the lift contribution from the pressure and suction side of the airfoil to the overall lift indicates that the qualitative lift evolution is reproduced even if the pressure side contribution is neglected. This reveals important characteristics of such airfoil dynamics, which can be exploited in future experimental studies, where direct aerodynamic force and moment measurements are greatly inhibited by dominating inertial forces

Automation in Surgery: The Surgeons' Perspective on Human Factors Issues of Image-Guided Navigation

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Image-guided navigation (IGN) systems support the surgeon in navigating through the patients' anatomy. Previous research on IGN has focused on technical feasibility and clinical applications. Yet, as the introduction of IGN corresponds to a partial automation of the surgeon's task, well known issues of human-automation interaction might play a crucial role for the success of IGN as well. The present study represents a first attempt to assess the impact of IGN on four key issues of human automation-interaction, i.e., workload, situation awareness, trust, and skill degradation, from the surgeons' perspective. A nation-wide survey among 213 German surgeons from 94 different hospitals was conducted. Results revealed (1) a workload-shift due to IGN rather than a reduction of workload, (2) benefits of IGN with respect to situation awareness, (3) comparatively high levels of perceived reliability, trust and reliance, and (4) skill degradation as a possible risk, albeit only for inexperienced surgeons

Untersuchung selbsterregter Reibungsschwingungen mit Hilfe eines numerischen Simulationsverfahrens

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Investigating the Effect of Conflicting Goals and Transparency on Trust and Collaboration in Multi-Team Systems

In Air Traffic Management (ATM) multiple teams have to collaborate to achieve efficient and safe operation. Multiple-team operations rely on communication and information sharing between the team members. In this field, multi-team systems (MTSs) are the most common form of organization. The interface between the organizations involved (e.g. air traffic control, cockpit crews, airports) is of central importance. Apart from a common goal, different stakeholders may pursue individual goals governed by their own company culture or policies. Therefore, simply sharing all available information may not be enough to ensure safe and efficient operation. As part of the project ITC (Inter-Team Collaboration), an experimental study with 48 teams of three (n=144) has just started to investigate the impact that conflicting goals have on communication and collaboration. Additionally, it examines whether and how transparency in roles, processes, and goals can affect performance, communication, and trust in multi-team systems. In the synthetic task environment (STE) ConCenT (Control Center Task Environment), teams of three have to collaborate to detect system failures in time, determine their causes, and decide on a solution in order to ensure successful production processes. Measurements of performance, perceived trust, communication, and gaze data will be analyzed to examine and compare different coordination and communication patterns on a group level. Results of the study will identify factors that may facilitate or hinder collaborative work processes in an MTS, thus enabling the validation of an approach to improve collaboration through transparency and mutual trust

Determining job requirements for the next aviator generation

The aviation industry is envisioning a tremendous growth of air traffic within the next two decades. New technologies and operational concepts will be the key enablers to accommodate the increasing amount of movements in a safe, efficient and environment friendly manner. Current working concepts reach from improved interoperability of national ATM systems, via satellite based navigation, collaborative decision making, and self separation of aircraft up to fully automated air-ground-space systems. It can be expected that the introduction of such concepts will have a significant impact on the working conditions and job requirements of future air traffic controllers and pilots, who were selected on traditional job profiles reflecting the current and past operational settings. Our paper is presenting elements of a prospective job analysis of future aviators assigned to specific operational tasks within the future air transport system. Results will be based on reviews of available international concept papers, conducted future workshops with present job holders and low fidelity simulation runs of collaborative air traffic control and aircraft separation tasks. Relevant en-route and arrival scenarios will be discussed and presented at the symposium with some preliminary data of the initial tryout studies