Airfoil performance degradation by coupling effects of supercooled raindrop icing and heavy rainfall

2016 ◽  
Vol 231 (13) ◽  
pp. 2384-2395 ◽  
Author(s):  
Zhenlong Wu ◽  
Yihua Cao
Keyword(s):  
Numerical Study ◽  
Leading Edge ◽  
Aircraft Design ◽  
Heavy Rain ◽  
Aerodynamic Performance ◽  
Pilot Training ◽  
Ice Accretion ◽  
Coupling Effects ◽  
Two Phase ◽  
Aircraft Aerodynamics

Icing and rainfall are the two critical meteorological factors that threaten the aircraft flight safety. A number of previous studies have shown their individual influences on aircraft aerodynamics; however, to date no studies on their coupling effects exist. In this paper, a numerical study is conducted to focus on the aerodynamic performance of a NACA 23012 airfoil exposed to heavy rain in the presence of an ice accretion by supercooled raindrop on the leading edge. An Eulerian–Lagrangian two-phase flow approach developed for rain simulation in our previous work is adopted here with some improvement in the turbulence model. A series of new phenomena about the aerodynamic performance and wake characteristics under the coupling effects of ice accretion and rainfall are found and discussed. These results do not seem to have been published previously and should be of significance to the aircraft industry for improved aircraft design and pilot training.

scholarly journals Numerical Analysis of Effect of Leading-Edge Rotating Cylinder on NACA0021 Symmetric Airfoil

2019 ◽  
Vol 4 (7) ◽  
pp. 11-17
Author(s):  
Md. Abdus Salam ◽  
Vikram Deshpande ◽  
Nafiz Ahmed Khan ◽  
M. A. Taher Ali
Keyword(s):  
Free Stream ◽  
Numerical Study ◽  
Tangential Velocity ◽  
Leading Edge ◽  
Rotating Cylinder ◽  
Aerodynamic Performance ◽  
Stream Velocity ◽  
Surface Boundary ◽  
Lower Velocity ◽  
Numerical Studies

The moving surface boundary control (MSBC) has been a Centre stage study for last 2-3 decades. The preliminary aim of the study was to ascertain whether the concept can improve the airfoil characteristics. Number of experimental and numerical studies pointed out that the MSBC can superiorly enhance the airfoil performance albeit for higher velocity ratios (i.e. cylinder tangential velocity to free stream velocity). Although abundant research has been undertaken in this area on different airfoil performances but no attempt was seen to study effect of MSBC on NACA0021 airfoil for and also effects of lower velocity ratios. Thus, present paper focusses on numerical study of modified NACA 0021 airfoil with leading edge rotating cylinder for velocity ratios (i.e.) between 1 to 1.78 at different angles of attack. The numerical study indicates that the modified airfoil possess better aerodynamic performance than the base airfoil even at lower velocity ratios (i.e. for velocity ratios 0.356 and beyond). The study also focusses on reason for improvement in aerodynamic performance by close look at various parameters.

Computation of Aerodynamic Performance Deterioration of Wind Turbine Blade Due to Ice Accretion

2003 ◽  
Author(s):  
Kousuke Nushi ◽  
Shingo Kasai ◽  
Kazuyuki Toda ◽  
Makoto Yamamoto ◽  
Makoto Iida ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Leading Edge ◽  
Aerodynamic Performance ◽  
Wind Turbine Blade ◽  
Ice Accretion ◽  
Power Generator ◽  
Wind Power Generator ◽  
Performance Deterioration ◽  
Severe Deterioration

The attention for a wind power-generator has been attracted as one of the solutions for the environmental problems. When a wind turbine is operated in winter, supercooled water droplets impinge on the blade surface, and as the result ice accretes around the leading edge. It is well known that the occurrence of ice accretion on the wind turbine blade can lead to the severe deterioration of aerodynamic performance. However, the experiment is difficult, because it is not easy to create repeatedly the accretion conditions in a laboratory. Therefore, CFD is expected as a useful tool to predict and investigate the phenomena. In the present study, we develop the ice accretion code, and apply it to the MEL wind turbine blade. From the computational results, the shape of the ice-accreted blade and the deterioration of aerodynamic performance are numerically investigated.

Aerodynamic Performance Investigation under the Influence of Heavy Rain of a NACA 0012 Airfoil for Wind Turbine Applications

2012 ◽  
Vol 6 (6) ◽  
pp. 1228-1235
Author(s):  
Eleni C. Douvi ◽  
Dionissios P. Margaris
Keyword(s):  
Flow Field ◽  
Wind Turbine ◽  
Heavy Rain ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Spherical Particles ◽  
Discrete Phase Model ◽  
Two Phase ◽  
Naca0012 Airfoil ◽  
The Impact

The study of the prediction of the flow field and aerodynamic characteristics of a NACA0012 airfoil in simulated heavy rain, using a computational fluid dynamics code is presented. The simulation of rain is accomplished by using the two-phase flow Discrete Phase Model, which is available in the CFD code. Spherical particles are tracked through the two-dimensional, incompressible air flow field over a NACA0012 airfoil, at a simulated rain rate of 1000 mm/h and operating at Reynolds numbers Re=1×106 and Re=3×106. To validate the CFD developed model, the results are compared with well-established and published experimental data, showing good agreement. The aim of the work was to show the behavior of the airfoil at these conditions and to establish a verified solution method. Lift and drag coefficients are computed at various angles of attack in both dry and wet conditions and the results are compared to show the effects of rain at airfoil performance. The impact of rain on wind turbine performance is also analyzed. It is concluded that rain causes degradation of aerodynamic performance, especially lift is decreased and drag is increased.

scholarly journals The stability of two-phase flow over a swept wing

1996 ◽  
Vol 329 ◽  
pp. 247-273 ◽  
Author(s):  
Adrian V. Coward ◽  
Philip Hall
Keyword(s):  
Porous Plate ◽  
Leading Edge ◽  
Water Layer ◽  
Heavy Rain ◽  
Travelling Wave ◽  
Swept Wing ◽  
Two Phase ◽  
Crude Model ◽  
Fluid Properties ◽  
The Stability

We use numerical and asymptotic techniques to study the stability of a two-phase air/water flow above a flat porous plate. This flow is a model of the boundary layer which forms on a yawed cylinder and can be used as a useful approximation to the air flow over swept wings. The air and water form an immiscible interface which can destabilize the flow, leading to travelling wave disturbances which move along the attachment line. This instability occurs for lower Reynolds numbers than is the case in the absence of a water layer. The two-fluid flow can be used as a crude model of the effect of heavy rain on the leading edge of a swept wing.We also investigate the instability of inviscid stationary modes. We calculate the effective wavenumber and orientation of the stationary disturbance when the fluids have identical physical properties. Using perturbation methods we obtain corrections due to a small stratification in viscosity, thus quantifying the interfacial effects. Our analytical results are in agreement with the numerical solution which we obtain for arbitrary fluid properties.

scholarly journals Aerodynamic and performance characteristics of a passive leading edge Kruger flap at low Reynolds numbers

2012 ◽  
Vol 116 (1181) ◽  
pp. 757-767 ◽  
Author(s):  
V. M. Moraris ◽  
N. J. Lawson ◽  
K. P. Garry
Keyword(s):  
Numerical Study ◽  
Leading Edge ◽  
Detailed Comparison ◽  
Reynolds Numbers ◽  
Aerodynamic Performance ◽  
Low Reynolds Numbers ◽  
Initial Stage ◽  
And Performance ◽  
High Angles Of Attack ◽  
Basic Configuration

Abstract An experimental and numerical study was performed on a Clark Y aerofoil with a 10% chord leading edge Kruger flap to examine its aerodynamic performance at Reynolds numbers of 0·6 × 106, 1 × 106, and 1·6 × 106, to help to identify the forces and moments acting on a basic configuration. A detailed comparison of the numerical and experimental data is presented in this paper. The leading edge flap was effective at high angles of attack with an increase in CL of up to 18% over a conventional no flap configuration and delayed separation by up to 3°. The moments around the Kruger flap rotation point were calculated from the numerical analysis as an initial stage in the design of a UAV passive flap system and they are also presented in the paper.

A Numerical Study of Concurrent Flame Propagation Over Methanol Pool Surface

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Seik Mansoor Ali ◽  
Vasudevan Raghavan ◽  
K. Velusamy ◽  
Shaligram Tiwari
Keyword(s):  
Flame Spread ◽  
Numerical Study ◽  
Leading Edge ◽  
Reacting Flow ◽  
Atmospheric Conditions ◽  
Air Velocity ◽  
Two Phase ◽  
Spread Velocity ◽  
Pool Surface ◽  
Initial Flame

Concurrent flame spread over methanol pool surface under atmospheric conditions and normal gravity has been numerically investigated using a transient, two-phase, reacting flow model. The average flame spread velocities for different concurrent air velocities predicted using the model are quite close to the experimental data available in the literature. As the air velocity is increased, the fuel consumption rate increases and aids in faster flame spread process. The flame initially anchors around the leading edge of the pool and the flame tip spreads over the pool surface. The rate of propagation of flame tip along the surface is seen to be steady without fluctuations. The flame spread velocity is found to be nonuniform as the flame spreads along the pool surface. The flame spread velocity is seen to be higher initially. It then decreases up to a point when the flame has propagated to around 40% to 50% of the pool length. At this position, a secondary flame anchoring point is observed, which propagates toward the trailing edge of the pool. As a result, there is an increasing trend observed in the flame spread velocity. As the air velocity is increased, the initial flame anchoring point moves downstream of the leading edge of the fuel pool. The variations of interface quantities depend on the initial flame anchoring location and the attainment of thermodynamic equilibrium between the liquid- and gas-phases.

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