The development of a capability for aerodynamic testing of large-scale wing sections in a simulated natural rain environment

Bezos, Gaudy M.; Cambell, Bryan A.; Melson, W. Edward

doi:10.2514/6.1989-762

Cited by 6 publications

(4 citation statements)

References 2 publications

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“…But this phenomenon is not well understood. No other researcher like Dunham [10], Campbell and Bezos [12], Bezos et al [13,14], Valentine [21], and Valentine and Decker [22,23] predicted lift and stall angle increment at high AOA in heavy rain conditions in their studies. For our studies, the stall angle is 15 deg.…”

Section: Simulation and Resultsmentioning

confidence: 99%

“…For a rainfall rate of 200 cm∕h, a decrease in lift up to 30%, an increase in drag up to 25%, and decrease in stall angle of attack up to 6 deg were estimated. In the early 1980s, an experimental research program was established at NASA Langley Research Center to determine the heavy rain effects on the aerodynamic efficiency of NACA 64210, NACA 0012, and NACA 23015 airfoils [10][11][12][13][14]. The results of these programs indicated an increase in drag, decrease in lift, and earlier onset of the stall for the airfoils in heavy rain environment.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Study of Aerodynamic Efficiency of a Wing in Simulated Rain Environment

Ismail

Cao

et al. 2014

Journal of Aircraft

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In this study, heavy rain effects on the aerodynamic efficiency of a NACA 0012 wing with an aspect ratio of 2 have been anticipated at a Reynolds number of 2.2 × 10 6 . In the numerical simulation, the preprocessing software Gridgen has been used for creation of the geometry and generation of the mesh, and Fluent software is used as a solver. Discrete phase modeling in a Langrangian frame of reference has been used to simulate the rain particles dispersed in the continuous phase using a two-phase flow approach. The coupling between the two phases and its impact on both phases has been included. In this study, significant decrease in aerodynamic efficiency of the NACA 0012 threedimensional wing has been observed. The lift and lift to drag ratio decreased up to ∼15-18% for liquid water content of 30 and 39 g∕m 3 , respectively. The maximum decrease in lift has been observed for angle of attack of 6-14 deg, at which airplanes usually perform takeoff and landing. It is found that the heavy rain causes premature boundary-layer transition at low angle of attack and separation due to increase of shear stresses at high angle of attack. The water film layer formed on the surface of the wing and the splashed particles into the air are the main causes of the degradation in aerodynamic efficiency of the three-dimensional wing. The results obtained in the numerical study are compared with the experimental results, and they are in good agreement. This study will be useful for aviation engineers and scientists to design airplanes and unmanned aerial vehicles capable of flying in severe weather conditions.

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Section: Simulation and Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical Study of Aerodynamic Efficiency of a Wing in Simulated Rain Environment

Ismail

Cao

et al. 2014

Journal of Aircraft

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“…3 These believed that it was not enough to make aircraft fall and crash because of the little effect on aircraft aerodynamic penalties due to rainfall, except for blurring pilot's line of sight, possibly leading to failure of the instruments, etc. Until aircraft accidents due to rainfall occurred, 4,5 studies on aerodynamic performance degradation in the rain condition were conducted by using the experimental and theoretical methods [6][7][8] in order to explore the potential causes of flight accidents. Studies on water film flow on airfoil surfaces [9][10][11] and rain erosion 12,13 were also conducted.…”

Section: Introductionmentioning

confidence: 99%

Helicopter flight dynamics with simulated rainfall

Cao

2022

Proceedings of the Institution of Mechanical Engineers, Part G:

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Sustaining flight operation that encounters with rainfall might be a challenge to a pilot due to lacking of understanding flight dynamics in the rain conditions. This paper, combined with a computational fluid dynamics (CFD) technique, develops a nonlinear flight dynamics model in the rain conditions that can be capable of exploring UH-60A single-rotor helicopter flight dynamics in the rain conditions, including trim, stability, and controllability. Firstly, in order to obtain a data-driven basis relating to multiple working conditions of the blades, a CFD-based method of simulation of the blade airfoil in the conditions of the angles of attack ranging from −26° to 26° and under a thunderstorm heavy rain scenario when the rate of rainfall is 1500 mm/h is developed. Then, these data are incorporated into a nonlinear flight dynamics model in the form of coefficient increments. Numerical simulations are conducted in the range of the flight velocities from 0 knots to 160 knots. The quantitative results indicate that rainfall degrades the blade airfoil aerodynamic performance and increases the rotor torque and required power, affecting the helicopter trim, stability, and controllability. More importantly, helicopter that flies in a small or moderate flight velocity and that encounters rainfall might be a relative serious case, which should be paid attention to.

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“…In 1987 NASA and FAA developed a large-scale, ground based facility at Langley Aircraft Dynamic Facility (ALTF) led by Bezos to predict the effect of heavy rain on the aerodynamic efficiency of airfoils at realistic Reynolds numbers [2]. They chose NACA 64-210 airfoil for experiment.…”

Section: Introductionmentioning

confidence: 99%

Airfoils Aerodynamic Performance Analysis in Heavy Rain

Ismail

2012

AMM

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Heavy rainfall greatly affects the aerodynamic performance of the aircraft. There are many accidents of aircraft caused by aerodynamic efficiency degradation due to heavy rain. In this paper we have studied the heavy rain effects on the aerodynamic efficiency of NACA 64210 and NACA 0012 airfoils with cruise and landing configuration. For our analysis, CFD method and preprocessing grid generator are used as our main analytical tools, and the simulation of rain is accomplished via two phase flow approach named as Discrete Phase Model (DPM). Raindrops are assumed to be non-interacting, non-deforming, non evaporating and non spinning spheres. Both cruise and landing configurations of airfoils exhibited significant reduction in lift and increase in drag for a given lift condition in simulated rain. Our results are in good agreement with the experimental results. It is expected that the quantitative information gained in this paper will be useful to the operational airline industry and greater effort such as small scale and full scale flight tests should put in this direction to further improve aviation safety.

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The development of a capability for aerodynamic testing of large-scale wing sections in a simulated natural rain environment

Cited by 6 publications

References 2 publications

Numerical Study of Aerodynamic Efficiency of a Wing in Simulated Rain Environment

Numerical Study of Aerodynamic Efficiency of a Wing in Simulated Rain Environment

Helicopter flight dynamics with simulated rainfall

Airfoils Aerodynamic Performance Analysis in Heavy Rain

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