Far-field noise prediction for jets using large-eddy simulation and Ffowcs Williams–Hawkings method

2016 ◽  
Vol 15 (8) ◽  
pp. 757-780 ◽  
Author(s):  
Iftekhar Z Naqavi ◽  
Zhong-Nan Wang ◽  
Paul G Tucker ◽  
M Mahak ◽  
Paul Strange
Keyword(s):  
Large Eddy Simulation ◽  
Noise Prediction ◽  
Far Field ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Field Noise

Far Field Noise Prediction for Subsonic Hot and Cold Jets Using Large-Eddy Simulation

2014 ◽  
Author(s):  
Zhong-Nan Wang ◽  
Iftekhar Z. Naqavi ◽  
Mahak Mahak ◽  
Paul Tucker ◽  
Xin Yuan ◽  
...  
Keyword(s):  
Large Eddy Simulations ◽  
Noise Prediction ◽  
Far Field ◽  
Temperature Ratio ◽  
Mean Velocity ◽  
Eddy Simulation ◽  
Large Eddy ◽  
The Mean ◽  
Simulation Results ◽  
Field Noise

Large eddy simulations are performed for hot and cold single stream jets with an acoustic Mach number of (Ma = Vj/a∞ = 0.875). The temperature ratio (Tj/T∞) for the hot jet is 2.7 and for the cold jet it is 1.0. Grids with 34 million points are used. The simulation results for the flow field are in encouraging agreement with the mean velocity and Reynolds stress measurements. The Ffowcs Williams-Hawkings (FW-H) equation is used to predict the far-field noise. In this study four cylindrical FW-H surfaces around the jet at various radial distances from the centreline are used. The FW-H surfaces are closed at the downstream end with multiple endplates. These endplates are at x = 25.0D – 30.0D with Δ = 0.5D apart. It is shown that surfaces close to jet get affected with pseudo sound. To avoid pseudo sound, surfaces must be placed in the irrotational region. To account for all the acoustic signals end plates are necessary. However, a simple averaging process to cancel pseudo sound at the end plates is not sufficient.

Wake-Airfoil Interaction as Broadband Noise Source: A Large-Eddy Simulation Study

2005 ◽  
Vol 4 (1-2) ◽  
pp. 93-115 ◽  
Author(s):  
Jérôme Boudet ◽  
Nathalie Grosjean ◽  
Marc C. Jacob
Keyword(s):  
Large Eddy Simulation ◽  
Particle Image ◽  
Broadband Noise ◽  
Far Field ◽  
Acoustic Analogy ◽  
Eddy Simulation ◽  
Naca0012 Airfoil ◽  
Image Velocimetry ◽  
Large Eddy ◽  
Proper Orthogonal

A large-eddy simulation is carried out on a rod-airfoil configuration and compared to an accompanying experiment as well as to a RANS computation. A NACA0012 airfoil (chord c = 0.1 m) is located one chord downstream of a circular rod (diameter d = c/10, Red = 48 000). The computed interaction of the resulting sub-critical vortex street with the airfoil is assessed using averaged quantities, aerodynamic spectra and proper orthogonal decomposition (POD) of the instantaneous flow fields. Snapshots of the flow field are compared to particle image velocimetry (PIV) data. The acoustic far field is predicted using the Ffowcs Williams & Hawkings acoustic analogy, and compared to the experimental far field spectra. The large-eddy simulation is shown to accurately represent the deterministic pattern of the vortex shedding that is described by POD modes 1 & 2 and the resulting tonal noise also compares favourably to measurements. Furthermore higher order POD modes that are found in the PIV data are well predicted by the computation. The broadband content of the aerodynamic and the acoustic fields is consequently well predicted over a large range of frequencies ([0 kHz; 10 kHz]).

Wall-Resolved Large Eddy Simulation of a Realistic Turbofan Rotor for Noise Prediction

2021 ◽  
Author(s):  
Pavel Kholodov ◽  
Regis Koch ◽  
Marlène Sanjosé ◽  
Stephane Moreau
Keyword(s):  
Large Eddy Simulation ◽  
Noise Prediction ◽  
Eddy Simulation ◽  
Large Eddy

Noise prediction via large eddy simulation: Application to radial fans

2009 ◽  
Vol 57 (3) ◽  
pp. 169 ◽  
Author(s):  
Esra Sorguven ◽  
Yilmaz Dogan ◽  
Faruk Bayraktar ◽  
Kenan Y. Sanliturk
Keyword(s):  
Large Eddy Simulation ◽  
Noise Prediction ◽  
Eddy Simulation ◽  
Large Eddy

Jet noise prediction via coupling large eddy simulation and stochastic modeling

2017 ◽  
Vol 142 (4) ◽  
pp. 2491-2491
Author(s):  
Joshua D. Blake ◽  
VASILEIOS SASSANIS ◽  
David Thompson ◽  
Adrian Sescu ◽  
Yuji Hattori
Keyword(s):  
Large Eddy Simulation ◽  
Stochastic Modeling ◽  
Jet Noise ◽  
Noise Prediction ◽  
Eddy Simulation ◽  
Large Eddy

Large Eddy Simulations of Supersonic Impinging Jets

2012 ◽  
Author(s):  
James P. Erwin ◽  
Neeraj Sinha ◽  
Gregory P. Rodebaugh
Keyword(s):  
Impinging Jet ◽  
Impinging Jets ◽  
Far Field ◽  
Nozzle Throat ◽  
Aircraft Carrier ◽  
Eddy Simulation ◽  
Instability Modes ◽  
Large Eddy ◽  
Field Noise ◽  
Short Takeoff And Landing

Supersonic impinging jet flowfields contain self-sustaining acoustic feedback features that create high levels of discrete frequency tonal noise. These types of flowfields are typically found with short takeoff and landing military aircraft as well as jet blast deflector operations on aircraft carrier decks. The US Navy has a goal to reduce the noise generated by these impinging jet configurations and is investing in computational aeroacoustics to aid in the development of noise reduction concepts. In this paper, implicit Large Eddy Simulation (LES) of impinging jet flow-fields are coupled with a far-field acoustic transformation using the Ffowcs Williams and Hawkings (FW-H) equation method. The LES solves the noise generating regions of the flow in the nearfield, and the FW-H transformation is used to predict the far-field noise. The noise prediction methodology is applied to a Mach 1.5 vertically impinging jet at a stand-off distance of five nozzle throat diameters. Both the LES and FW-H acoustic predictions compare favorably with experimental measurements. Time averaged and instantaneous flowfields are shown. A calculation performed previously at a stand-off distance of four nozzle throat diameters is revisited with adjustments to the methodology including a new grid, time integrator, and longer simulation runtime. The calculation exhibited various feedback loops which were not present before and can be attributed to an explicit time marching scheme. In addition, an instability analysis of two heated jets is performed. Tonal frequencies and instability modes are identified for the sample problems.

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