Numerical Analysis of Wing-Tip Flows and Aerodynamic Sound Generated From the Flows

2011 ◽  
Author(s):  
Kazuaki Yamasari ◽  
Yasumasa Suzuki ◽  
Chisachi Kato ◽  
Masaaki Ohnishi ◽  
Kentaro Yatuduka ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Measured Data ◽  
Sound Level ◽  
Tip Vortex ◽  
Far Field ◽  
Aerodynamic Sound ◽  
Eddy Simulation ◽  
Surface Pressure Distribution ◽  
Wing Tip ◽  
Field Sound

We study the flow and the aerodynamic sound generated from the wing-tip using numerical analysis. The objective of this study is to clarify the contribution to level of sound generated from the wing-tip. We predicted the aerodynamic sound by the separation method based on Lighthill analogy. The model is a rectangular wing having NACA0012 profiles. The shape of wing-tip is blunt, which has sharp edges. The Reynolds number based on the chord length and uniform velocity is 2×105. The angle of attack is 9 degree which is the lifting condition. The flow around the airfoil is predicted by Large-eddy simulation of turbulent incompressible flow. Current results indicated that the simulated surface pressure distribution and pressure power spectrum agreed quantitatively with measured data. In this result, we calculated the Lighthill tensor from velocity and density of air. In addition we discussed the wing-tip vortex structure and its origin. The far field sound predicted by Lighthill tensor shows a similar tendency to the measured data. To investigate the contribution of the overall level around the airfoil with wing-tip, the far field sound was predicted by Lighthill tensor only around wing-tip. The aerodynamic sound level generated from wing-tip is small compared to the overall level of the sound all around airfoil, however it remains possible that contribute to particular frequency band.

1009 Analysis of Aerodynamic Sound Sources in Wing Tip Flow and Prediction of Far-field Sound generated from the Flow

2010 ◽  
Vol 2010 (0) ◽  
pp. 277-278
Author(s):  
Kazuaki YAMASARI ◽  
Fabbro NICOLAS ◽  
Masaaki OHNISHI ◽  
Kentaro YATUDUKA ◽  
Chisachi KATO ◽  
...  
Keyword(s):  
Far Field ◽  
Sound Sources ◽  
Aerodynamic Sound ◽  
Wing Tip ◽  
Field Sound

Large Eddy Simulation of Unsteady Flow Around a Door Mirror Model and Prediction of Resulting Far-Field Sound

2005 ◽  
Author(s):  
Hong Wang ◽  
Chisachi Kato ◽  
Yoshinobu Yamade ◽  
Yang Guo
Keyword(s):  
Large Eddy Simulation ◽  
Unsteady Flow ◽  
Surface Pressure ◽  
Measured Data ◽  
Far Field ◽  
Acoustic Analogy ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Mesh Resolution ◽  
Field Sound

Unsteady flow and resulting far-field sound are numerically investigated for a door mirror model in this paper. The flow field is solved by Large Eddy Simulation (LES) with the dynamic Smagorinsky model while the surface pressure fluctuations obtained by LES are used to predict the far-field sound based on the acoustic analogy. For the prediction of the far-field sound, Curle’s equation is used under the assumption that the characteristic length of the door mirror model is much smaller than the wavelength of the sound. Comparisons between the predicted and measured data are presented in terms of the time-averaged and fluctuating surface pressure distributions as well as the far-field sound spectrum. Reasonably good agreements have been obtained between the predicted and the measured data. Investigation of the effects of the mesh resolution also shows that improved results can be obtained efficiently if the mesh resolution is increased along the stream-wise direction within the separation region and wake region.

Large-eddy simulation of wing tip vortex in the near field

2008 ◽  
Vol 22 (5) ◽  
pp. 289-330 ◽  
Author(s):  
Li Jiang ◽  
Jiangang Cai ◽  
Chaoqun Liu
Keyword(s):  
Large Eddy Simulation ◽  
Near Field ◽  
Tip Vortex ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Wing Tip Vortex ◽  
Wing Tip

An Overset Finite-Element Large-Eddy Simulation Method With Applications to Turbomachinery and Aeroacoustics

2003 ◽  
Vol 70 (1) ◽  
pp. 32-43 ◽  
Author(s):  
C. Kato ◽  
M. Kaiho ◽  
A. Manabe
Keyword(s):  
Finite Element ◽  
Fluid Flow ◽  
Flow Field ◽  
Moving Boundary ◽  
Far Field ◽  
Eddy Simulation ◽  
Unsteady Fluid Flow ◽  
Large Eddy ◽  
Unsteady Fluid ◽  
Field Sound

A numerical method for the prediction of an unsteady fluid flow in a complex geometry that involves moving boundary interfaces is presented in this paper. The method is also applicable to the prediction of the far-field sound that results from an unsteady fluid flow. The flow field is computed by large-eddy simulation (LES), while surface-pressure fluctuations obtained by the LES are used to predict the far-field sound. To deal with a moving boundary interface in the flow field, a form of the finite element method in which overset grids are applied from multiple dynamic frames of reference has been developed. The method is implemented as a parallel program by applying a domain-decomposition programming model. The validity of the proposed method is shown through two numerical examples: prediction of the internal flows of a hydraulic pump stage and prediction of the far-field sound that results from unsteady flow around an insulator mounted on a high-speed train.

Large-Eddy Simulation of a Wing Tip Vortex on Overset Grids

AIAA Journal ◽  
2006 ◽  
Vol 44 (6) ◽  
pp. 1229-1242 ◽  
Author(s):  
Ali Uzun ◽  
M. Yousuff Hussaini ◽  
Craig L. Streett
Keyword(s):  
Large Eddy Simulation ◽  
Tip Vortex ◽  
Overset Grids ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Wing Tip Vortex ◽  
Wing Tip

Detached Eddy Simulation of Unsteady Flow Field and Prediction of Aerodynamic Sound in a Half-Ducted Propeller Fan

2011 ◽  
Author(s):  
K. Kusano ◽  
J. H. Jeong ◽  
K. Yamada ◽  
M. Furukawa
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Tip Vortex ◽  
Vortical Flow ◽  
Detached Eddy Simulation ◽  
Acoustic Analogy ◽  
Aerodynamic Sound ◽  
Pressure Surface ◽  
Eddy Simulation ◽  
Ducted Propeller

Three-dimensional structures and unsteady nature of vortical flow fields in a half ducted propeller fan have been investigated by a detached eddy simulation (DES) based on k-ω two-equation turbulence model. The validity of the numerical simulation performed in the present study was demonstrated by the comparison to LDV measurement results. The simulation shows the tip vortex is so strong that it dominates the flow field near the rotor tip. The tip vortex does not impinge on the pressure surface of the adjacent blade directly, however it interacts with the shroud surface and induces a separation vortex on the shroud. Furthermore, this separation vortex interacts with the pressure surface of the adjacent blade. These flow structures cause high pressure fluctuation on the shroud surface and the blade pressure surface. Besides, sound pressure levels were predicted by Ffowcs William-Hawkings equation based on Lighthill’s acoustic analogy using the unsteady surface pressure data obtained by DES. As a result, the degree of contribution by each flow structure to overall sound has been estimated quantitatively.

scholarly journals Application of Large Eddy Simulation to Predict Underwater Noise of Marine Propulsors. Part 2: Noise Generation

2021 ◽  
Vol 9 (7) ◽  
pp. 778
Author(s):  
Julian Kimmerl ◽  
Paul Mertes ◽  
Moustafa Abdel-Maksoud
Keyword(s):  
Large Eddy Simulation ◽  
Near Field ◽  
Fluid Phase ◽  
Sound Level ◽  
Tip Vortex ◽  
Spectral Signature ◽  
Underwater Noise ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Free Running

Methods to predict underwater acoustics are gaining increased significance, as the propulsion industry is required to confirm noise spectrum limits, for instance in compliance with classification society rules. Propeller–ship interaction is a main contributing factor to the underwater noise emissions by a vessel, demanding improved methods for both hydrodynamic and high-quality noise prediction. Implicit large eddy simulation applying volume-of-fluid phase modeling with the Schnerr-Sauer cavitation model is confirmed to be a capable tool for propeller cavitation simulation in part 1. In this part, the near field sound pressure of the hydrodynamic solution of the finite volume method is examined. The sound level spectra for free-running propeller test cases and pressure pulses on the hull for propellers under behind ship conditions are compared with the experimental measurements. For a propeller-free running case with priory mesh refinement in regions of high vorticity to improve the tip vortex cavity representation, good agreement is reached with respect to the spectral signature. For behind ship cases without additional refinements, partial agreement was achieved for the incompressible hull pressure fluctuations. Thus, meshing strategies require improvements for this approach to be widely applicable in an industrial environment, especially for non-uniform propeller inflow.

scholarly journals Detached-Eddy Simulation of a Wing Tip Vortex at Dynamic Stall Conditions

2009 ◽  
Vol 46 (4) ◽  
pp. 1302-1313 ◽  
Author(s):  
Kaveh Mohamed ◽  
Siva Nadarajah ◽  
Marius Paraschivoiu
Keyword(s):  
Tip Vortex ◽  
Dynamic Stall ◽  
Detached Eddy Simulation ◽  
Eddy Simulation ◽  
Wing Tip Vortex ◽  
Wing Tip
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