Large-Eddy Simulation for Aerodynamic Noise From High-Lift Device

2009 ◽  
Author(s):  
Bassam Rakhshani ◽  
Antonio Filippone
Keyword(s):  
Large Eddy Simulation ◽  
Aerodynamic Noise ◽  
High Lift ◽  
Eddy Simulation ◽  
Large Eddy

Aerodynamic Noise Simulation of Propeller Fan by Large Eddy Simulation

2007 ◽  
Author(s):  
Shingo Hamada ◽  
Seiji Nakashima ◽  
Chisachi Kato ◽  
Yoshinobu Yamade
Keyword(s):  
Large Eddy Simulation ◽  
Pressure Rise ◽  
Tip Vortex ◽  
Aerodynamic Noise ◽  
Blade Surface ◽  
Frequency Range ◽  
Smagorinsky Model ◽  
Measured Velocity ◽  
Eddy Simulation ◽  
Large Eddy

In this paper, unsteady flow and aerodynamic noise are numerically investigated for a half-open type propeller fan used for outdoor air conditioner components. The flow field is calculated by Front Flow/Blue, which is based on Large Eddy Simulation (LES). The Standard Smagorinsky Model (SSM) and Dynamic Smagorinsky Model (DSM) were used as sub-grid scale models. Aerodynamic noise was calculated by Curle’s equation based on the pressure fluctuation on the blade surface computed by LES. The computed static pressure rise of the fan showed reasonable agreement with the measured equivalent. The time-averaged distributions of the three velocity components downstream of the blades were also compared with those measured by hotwire anemometry, which showed satisfactory agreement between the computed and measured velocity profiles. But the tip vortex passage which was detached from the blade surface predicted by LES was not stable as measured by the experiment. Finally, the predicted far-field sound spectrum agrees reasonably well with measurements in a frequency range of 100 to 1000 Hz although the sound pressure level was underpredicted in the lower frequency range.

Detailed Numerical Characterization of the Suction Side Laminar Separation Bubble for a High-Lift Low Pressure Turbine Blade by Means of RANS and LES

2016 ◽  
Author(s):  
Fabio Bigoni ◽  
Stefano Vagnoli ◽  
Tony Arts ◽  
Tom Verstraete
Keyword(s):  
Large Eddy Simulation ◽  
Separation Bubble ◽  
Suction Side ◽  
Reynolds Numbers ◽  
Laminar Separation Bubble ◽  
High Lift ◽  
Laminar Separation ◽  
Low Pressure Turbine ◽  
Eddy Simulation ◽  
Large Eddy

The scope of this work is to obtain a deep insight of the occurrence, development and evolution of the laminar separation bubble which occurs on the suction side of the high-lift T106-C low pressure turbine blade operated at correct engine Mach and Reynolds numbers. The commercial codes Numeca FINE/Turbo and FINE/Open were used for the numerical investigation of a set of three different Reynolds numbers. Two different CFD approaches, characterized by a progressively increasing level of complexity and detail in the solution, have been employed, starting from a steady state RANS analysis and ending with a Large Eddy Simulation. Particular attention was paid to the study of the open separation occurring at the lowest Reynolds number, for which a Large Eddy Simulation was performed in order to try to correctly capture the involved phenomena and their characteristic frequencies. In addition, the potentialities of the codes employed for the analysis have been assessed.

Wind Turbine Blade Tip Flow and Noise Prediction by Large-eddy Simulation

2004 ◽  
Vol 126 (4) ◽  
pp. 1017-1024 ◽  
Author(s):  
Oliver Fleig ◽  
Makoto Iida ◽  
Chuichi Arakawa
Keyword(s):  
Large Eddy Simulation ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Acoustic Emissions ◽  
Wind Turbine Blade ◽  
Tip Vortex ◽  
Aerodynamic Noise ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Blade Tip

The purpose of this research is to investigate the physical mechanisms associated with broadband tip vortex noise caused by rotating wind turbines. The flow and acoustic field around a wind turbine blade is simulated using compressible large-eddy simulation and direct noise simulation, with emphasis on the blade tip region. The far field aerodynamic noise is modeled using acoustic analogy. Aerodynamic performance and acoustic emissions are predicted for the actual tip shape and an ogee type tip shape. For the ogee type tip shape the sound pressure level decreases by 5 dB for frequencies above 4 kHz.

Computation of aerodynamic noise of centrifugal fan using large eddy simulation approach, acoustic analogy, and vortex sound theory

2007 ◽  
Vol 221 (11) ◽  
pp. 1321-1332 ◽  
Author(s):  
Q Liu ◽  
D Qi ◽  
H Tang
Keyword(s):  
Large Eddy Simulation ◽  
Broadband Noise ◽  
Scale Model ◽  
Aerodynamic Noise ◽  
Centrifugal Fan ◽  
Acoustic Analogy ◽  
Vortex Sound ◽  
Eddy Simulation ◽  
Sound Theory ◽  
Large Eddy

Large eddy simulation is applied to solve the unsteady three-dimensional viscous flow in the whole impeller-volute configuration of a centrifugal fan. The results of the simulation are used to predict the impeller-volute interaction and to obtain the unsteady pressure, velocity, and vorticity fluctuations in the impeller and volute casing. The simulation at the design point is carried out with the wall-adapting local eddy-viscosity subgrid-scale model and a sliding mesh technique is applied to consider the impeller-volute interaction. The results show that a strongly unsteady flow field occurs in the impeller and volute casing of the fan, and the flow is characterized with obvious pressure and vorticity fluctuations, especially at the tongue and at the blade wake region. The large pressure fluctuation at the tongue and the large fluctuation of the blade wake vorticity appear as the blade wake is passing the tongue. Acoustic analogy and vortex sound theory are used to compute the radiated dipole and quadrupole sound fields, which are in good agreement with the experiment. The sound results show that the vortex sound theory is convenient for the broadband noise computation, and the dipole sound is much higher than the quadrupole sound. The dipoles, distributed over the volute tongue surface, are the dominant sound source of the fan.

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