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Communication
Published in Mark W. Wiggins, Introduction to Human Factors for Organisational Psychologists, 2022
According to the National Transportation Safety Board (1988), the most significant factor involved in the crash was the failure of the flight crew to extend the flaps and leading-edge slats prior to take-off. The flaps and leading-edge slats extend the surface area of the wing, increasing the capacity of the aircraft to produce lift at a lower airspeed. It comprised an item on the pre-take-off checklist that, if not completed, would result in a significantly lower angle of climb than would normally be the case (see Figure 15.2). In the case of Flight 255, the inability to climb at the normal angle resulted in the collision with the building, following which the aircraft rotated through 90o before a second collision occurred.
Airborne dust-induced performance degradation in NREL phase VI wind turbine: a numerical study
Published in International Journal of Green Energy, 2023
J. Zare, S. E. Hosseini, M. R. Rastan
Diab et al. (2015) explored dust accumulation on a number of widely used airfoil sections in the wind turbine industry by NACA, NREL, and DU, showing how passing time changes the blade profile and correspondingly the aerodynamic parameters. The results show that although the dust accumulation percentage is contingent on the blade type, the time and adverse effects have almost a linear rate. They suggested installing a leading edge slat to mitigate the adverse influences of dust contamination. Khalfallah and Koliub (Khalfallah and Koliub 2007) experimentally analyzed the effect of surface roughness due to dust accumulation on the performance of wind turbines. Moreover, the mechanism of dust accumulation was discussed. They observed that the roughness from the chord line toward the leading edge on blades of a stall-regulated, horizontal axis 300 kW wind turbine changes from 5% to 20%. Increasing the blade surface roughness generally reduces the effectiveness of the airfoil and the power output. However, the deterioration depends on the size and nature of the roughness, Reynolds number, and airfoil type. The 2D numerical study of Li et al. (2010) on the DU 95-W-180 airfoil determined the critical roughness height of a wind turbine airfoil as 0.5 mm. The lift and drag coefficient curves of the airfoil with sub-critical roughness decreases and increases, respectively. Beyond the critical value, the rate of variations are decelerated.
On turbulent flow and aerodynamic noise of generic side-view mirror with cell-centred finite difference method
Published in Journal of Turbulence, 2022
The turbulent flow past a half-cylinder body is featured by massive separation with significant fluctuations of pressure and velocity. Simulating such complex flows for both turbulence and aerodynamic noise requires not only appropriate eddy-resolving turbulence modelling but also low-dissipation and low-dispersion numerical methods. Nagata et al. [13] adopted a sixth-order WENOCU6-FP scheme to carry out direct numerical simulation of flows over an isolated sphere. Gao et al. [14] investigated the acoustics of flow over the 30P30N aerofoil with a high-order spectral difference method. Hoarau et al. [15] investigated a fourth-order accurate implicit residual smoothing scheme by carrying out LES of the VKI LS-89 turbine cascade. Li et al. [16] carried out an implicit large-eddy simulation (ILES) with a sixth-order compact finite difference method to investigate the acoustic resonances from a leading-edge slat configuration. Zhang et al. [17] employed a high-order flux reconstruction method to investigate flows over a DTMB 4119 propeller. Iyer et al. [18] applied the high-order PyFR code to petascale direct numerical simulation of flow over an MTU-T161 low-pressure turbine blade at a Reynolds number of 200,000.
Understanding pilot response to flight safety events using categorisation theory
Published in Theoretical Issues in Ergonomics Science, 2019
The crew also exceeded the speed limit for the wing slat and flap devices during the go-around, and this caused a variety of unusual system behaviour. They were not sure if they had exceeded the flap speed limits, despite experiencing an 18 knot and 47 knot exceedance at two different flap settings. Flap speed exceedances are not practiced as they are usually a consequence of inadvertent mismanagement of energy and flightpath. As a result the crew had no exemplar events to compare with their predicament or help with recognition. They then experienced two separate caution messages, ‘LE (leading edge) SLAT DISAGREE’ and ‘TE (trailing edge) FLAP DISAGREE’, partly the result of the speed exceedance and partly due to the incorrect execution of the checklist. These failure messages are conceptually similar, so prone to confusion, a situation exacerbated by their subsequent disappearance brought about by switching to alternate flap control. This illustrates how connecting failure messages with correct checklist selection can be difficult in non-typical scenarios, especially where system behaviour is less transparent and informative than previous flight crew encounters. The difficulty the crew had in managing these events was attributed to their unfamiliarity with this type of malfunction and the associated checklist. The infrequency of exemplar slat/flap events leads to weaker conceptual knowledge; a classic gradient that damaged the crews understanding of the situation and their behaviour. Unfortunately, a great number of flight safety events show this characteristic.