scholarly journals Experimental study on aerodynamic noise characteristics of high-lift configuration with a kind of variable gap leading-edge slat

2018 ◽  
Author(s):  
Weishuang Lu ◽  
Peiqing Liu ◽  
Hao Guo
Keyword(s):  
Experimental Study ◽  
Leading Edge ◽  
Aerodynamic Noise ◽  
High Lift ◽  
Noise Characteristics

scholarly journals Numerical Investigation of Unsteady Flow and Aerodynamic Noise Characteristics of an Automotive Axial Cooling Fan

2020 ◽  
Vol 10 (16) ◽  
pp. 5432
Author(s):  
Jang-oh Mo ◽  
Jae-hyuk Choi
Keyword(s):  
Unsteady Flow ◽  
Flow Behavior ◽  
Near Field ◽  
Leading Edge ◽  
Low Noise ◽  
Aerodynamic Noise ◽  
Frequency Noise ◽  
Field Region ◽  
Cooling Fan ◽  
Noise Characteristics

Low-speed axial cooling fans are frequently used to manage engine temperature by ensuring that adequate quantities of air pass through heat exchangers, even at low vehicle speeds or in the idle condition. This study aims to provide a better understanding of the unsteady flow behavior around an automotive axial cooling fan with seven blades and its impact on the aerodynamic noise generation. Large Eddy Simulation (LES) near the near-field region and the Ffowcs-Williams and Hawkinbygs (FW-H) method were performed to analyze the flow characteristics around the fan and predict the aerodynamic noise emitted from the fan under a constant rotational speed of 2100 rpm. The simulation results for the velocity distributions and aerodynamic noise were compared with the experimental data measured by single hot-wire probe and in a dead-sound room. The results showed a comparatively good agreement upstream and downstream from the fan and at two different receivers of 0.5 m and 1.0 m. When the fan was rotating, a strong tonal noise numerically existed near the leading edge of the blades at the tip and amounted to 110 dB sound pressure level (SPL) caused by the increasing angles of attack with the increasing radial velocity near the ring, which caused the entire air foil to emit a low-frequency noise. Furthermore, the different SPL decay characteristics of approximately 5 dB in the near-field region and 6 dB in the far-field region were observed each time the distance from the fan doubles. The findings of this research can provide important insights into the design of axial fans with low noise and high performance.

scholarly journals Analysis and Design of a Leading Edge with Morphing Capabilities for the Wing of a Regional Aircraft—Gapless Chord- and Camber-Increase for High-Lift Performance

2021 ◽  
Vol 11 (6) ◽  
pp. 2752
Author(s):  
Conchin Contell Asins ◽  
Volker Landersheim ◽  
Dominik Laveuve ◽  
Seiji Adachi ◽  
Michael May ◽  
...  
Keyword(s):  
Leading Edge ◽  
Bird Strike ◽  
High Lift ◽  
Analysis And Design ◽  
Actuation System ◽  
Aerodynamic Properties ◽  
Reinforced Plastic ◽  
Stall Angle ◽  
Carbon Fibre Reinforced Plastic ◽  
Electromechanical Actuation

In order to contribute to achieving noise and emission reduction goals, Fraunhofer and Airbus deal with the development of a morphing leading edge (MLE) as a high lift device for aircraft. Within the European research program “Clean Sky 2”, a morphing leading edge with gapless chord- and camber-increase for high-lift performance was developed. The MLE is able to morph into two different aerofoils—one for cruise and one for take-off/landing, the latter increasing lift and stall angle over the former. The shape flexibility is realised by a carbon fibre reinforced plastic (CFRP) skin optimised for bending and a sliding contact at the bottom. The material is selected in terms of type, thickness, and lay-up including ply-wise fibre orientation based on numerical simulation and material tests. The MLE is driven by an internal electromechanical actuation system. Load introduction into the skin is realised by span-wise stringers, which require specific stiffness and thermal expansion properties for this task. To avoid the penetration of a bird into the front spar of the wing in case of bird strike, a bird strike protection structure is proposed and analysed. In this paper, the designed MLE including aerodynamic properties, composite skin structure, actuation system, and bird strike behaviour is described and analysed.

Experimental study of heat transfer in the boundary layer of a flat plate with the impact of weak shock waves on the leading edge

2020 ◽  
Author(s):  
V. L. Kocharin ◽  
A. A. Yatskikh ◽  
D. S. Prishchepova ◽  
A. V. Panina ◽  
Yu. G. Yermolaev ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Experimental Study ◽  
Shock Waves ◽  
Flat Plate ◽  
Leading Edge ◽  
Weak Shock ◽  
The Impact

The effect of doors and cavity on the aerodynamic noise of fuselage nose landing gear

2021 ◽  
pp. 1475472X2110032
Author(s):  
Yongfei Mu ◽  
Jie Li ◽  
Wutao Lei ◽  
Daxiong Liao
Keyword(s):  
Separated Flow ◽  
Leading Edge ◽  
Landing Gear ◽  
Aerodynamic Noise ◽  
Sound Waves ◽  
Detached Eddy Simulation ◽  
Airframe Noise ◽  
Interference Phenomenon ◽  
Delayed Detached Eddy Simulation ◽  
The Doors

The aerodynamic noise of landing gears have been widely studied as an important component of the airframe noise. During take-off and landing, there are doors, cavity and fuselage around the landing gear. The noise caused by these aircraft components will interfere with aerodynamic noise generated by the landing gear itself. Hence, paper proposes an Improved Delayed Detached Eddy Simulation (IDDES) method for the investigation of the flow field around a single fuselage nose landing gear (NLG) model and a fuselage nose landing gear model with doors, cavity and fuselage nose (NLG-DCN) respectively. The difference between the two flow fields were analyzed in detail to better understand the influence of these components around the aircraft’s landing gear, and it was found that there is a serious mixing phenomenon among the separated flow from the front doors, the unstable shear layer falling off the leading edge of the cavity and the wake of the main strut which directly leads to the enhancement of the noise levels. Furthermore, after the noise sound waves are reflected by the doors several times, an interference phenomenon is generated between the doors. This interference may be a reason why the tone excited in the cavity is suppressed.

Flow Control for an Airfoil with Leading-Edge Rotation: An Experimental Study

2000 ◽  
Vol 37 (4) ◽  
pp. 617-622 ◽  
Author(s):  
Ahmed Z. Al-Garni ◽  
Abdullah M. Al-Garni ◽  
Saad A. Ahmed ◽  
Ahmet Z. Sahin
Keyword(s):  
Experimental Study ◽  
Flow Control ◽  
Leading Edge

Effects of Diffuser Vane Geometries on Compressor Performance and Noise Characteristics in a Centrifugal Compressor

2013 ◽  
Author(s):  
Yohei Morita ◽  
Nobumichi Fujisawa ◽  
Takashi Goto ◽  
Yutaka Ohta
Keyword(s):  
Centrifugal Compressor ◽  
Noise Level ◽  
Leading Edge ◽  
Broadband Noise ◽  
Frequency Noise ◽  
Numerical Techniques ◽  
Vaned Diffuser ◽  
Noise Characteristics ◽  
Edge Vortex ◽  
Compressor Performance

The effects of the diffuser vane geometries on the compressor performance and noise characteristics of a centrifugal compressor equipped with vaned diffusers were investigated by experiments and numerical techniques. Because we were focusing attention on the geometries of the diffuser vane’s leading edge, diffuser vanes with various leading edge geometries were installed in a vaned diffuser. A tapered diffuser vane with the tapered portion near the leading edge of the diffuser’s hub-side could remarkably reduce both the discrete frequency noise level and broadband noise level. In particular, a hub-side tapered diffuser vane with a taper on only the hub-side could suppress the development of the leading edge vortex (LEV) near the shroud side of the diffuser vane and effectively enhanced the compressor performance.

Sign in / Sign up

Export Citation Format

Share Document