Computation of Rotor Noise Generation in Grid Turbulence Using Large-Eddy Simulation

2015 ◽  
Author(s):  
Junye Wang ◽  
Kan Wang ◽  
Meng Wang
Keyword(s):  
Large Eddy Simulation ◽  
Grid Turbulence ◽  
Noise Generation ◽  
Eddy Simulation ◽  
Rotor Noise ◽  
Large Eddy

Large Eddy Simulation of Diesel Spray Combustion With a Multi-Component Drop Vaporization Model

2017 ◽  
Author(s):  
Xiaohua Ren ◽  
Lei Zhang ◽  
Zhongli Ji
Keyword(s):  
Experimental Data ◽  
Large Eddy Simulation ◽  
Combustion Process ◽  
Dynamic Structure ◽  
Diesel Spray ◽  
Grid Turbulence ◽  
Fuel Droplets ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Les Model

Large-eddy simulation (LES) of diesel spray and combustion was performed to study its improvement in the simulation of engine in-cylinder dynamics compared to the Reynolds-averaged simulation. For the LES, the dynamic structure approach was used to model the sub-grid turbulence and its interaction with the moving droplets in the spray. A multicomponent vaporization model (MCV) based on the continuous thermodynamics approach and a gamma distribution to describe the distribution of the numerous fuel components, was used to simulate the vaporization of diesel fuel droplets. The MCV model was imbedded into the LES framework in the KIVA-4 program. Using this LES model, a non-evaporative spray in a constant-volume chamber was first simulated. More realistic spray structures and improved agreements in the spray penetration with the experimental data were obtained by the LES compared to a Reynolds-averaged simulation of the same spray. A further simulation of an evaporative diesel spray and the subsequent combustion process using both LES and MCV models was also performed. Improved agreements with the experimental data in the spray structures and soot distributions were also observed using both models.

Noise Prediction of Pressure-Mismatched Jets Using Unstructured Large Eddy Simulation

2011 ◽  
Author(s):  
Yaser Khalighi ◽  
Frank Ham ◽  
Parviz Moin ◽  
Sanjiva K. Lele ◽  
Robert H. Schlinker
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Flow ◽  
Three Dimensional ◽  
Empirical Models ◽  
Nozzle Geometry ◽  
High Fidelity ◽  
Noise Generation ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Generation Mechanisms

It is our premise that significant new advances in the understanding of noise generation mechanisms for jets and realistic methods for reducing this noise can be developed by exploiting high-fidelity computational fluid dynamics: namely large eddy simulation (LES). In LES, the important energy-containing structures in the flow are resolved explicitly, resulting in a time-dependent, three-dimensional realization of the turbulent flow. In the context of LES, the unsteady flow occurring in the jet plume (and its associated sound) can be accurately predicted without resort to adjustable empirical models. In such a framework, the nozzle geometry can be included to directly influence the turbulent flow including its coherent and fine-scale motions. The effects of propulsion system design choices and issues of integration with the airframe can also be logically addressed.

Application of Actuator Line Model for Large Eddy Simulation of Rotor Noise Control

2021 ◽  
Vol 108 ◽  
pp. 106405
Author(s):  
Yann Delorme ◽  
Ronith Stanly ◽  
Steven H. Frankel ◽  
David Greenblatt
Keyword(s):  
Large Eddy Simulation ◽  
Noise Control ◽  
Line Model ◽  
Eddy Simulation ◽  
Rotor Noise ◽  
Large Eddy ◽  
Actuator Line Model

scholarly journals LARGE-EDDY SIMULATION OF NOISE GENERATED BY PULSED SUPERSONIC JETS

Akustika ◽  
2019 ◽  
Vol 34 ◽  
pp. 136-140
Author(s):  
Pavel Chernyshov ◽  
Vladislav Emelyanov ◽  
Aleksey Tsvetkov ◽  
Konstantin Volkov
Keyword(s):  
Numerical Simulation ◽  
Large Eddy Simulation ◽  
Supersonic Jet ◽  
Supersonic Jets ◽  
Jet Flows ◽  
Noise Generation ◽  
Noise Sources ◽  
Jet Streams ◽  
Eddy Simulation ◽  
Large Eddy

Development of models and methods of modelling and simulation of the mechanisms of noise generation in jet streams plays an important role in various engineering applications due to strict requirements for noise produced by different industrial devices as well as the possibilities of using sound in technological processes. The computational tools of numerical simulation of gas dynamics and aeroacoustics processes in supersonic jet flows are considered, and noise sources and noise generation mechanisms in supersonic jets are discussed. The approach to numerical simulation is based on large-eddy simulation technique allowing to resolve eddy structures in the flowfield and to predict noise generation more accurately compared to the existing tools. The results obtained show the structure of under- and over-expanded supersonic jets and could be used to calculate sources of noise in supersonic flows.

Large-Eddy Simulation of the Aerodynamic and Aero-Acoustic Performance of an Industrial Fan Designed for Tunnel Ventilation

2012 ◽  
Author(s):  
Domenico Borello ◽  
Stefano Bianchi ◽  
Alessandro Corsini ◽  
Franco Rispoli ◽  
Anthony G. Sheard
Keyword(s):  
Large Eddy Simulation ◽  
Unsteady Aerodynamics ◽  
Secondary Flows ◽  
Reverse Direction ◽  
Grid Turbulence ◽  
Ambient Conditions ◽  
Tunnel Ventilation ◽  
Eddy Simulation ◽  
Aerodynamic Properties ◽  
Large Eddy

The development of industrial fans traditionally relies upon the use of empirical correlations and experimental analyses to validate both aerodynamic and acoustic aspects of fan performance. This paper presents the development of a computational based method focused on the prediction of unsteady aerodynamics and modeling of aero-acoustic sources. The authors applied the study to a single fan from a new range of large tunnel ventilation axial flow fans. The fan specification required mechanical and aerodynamic properties that would enable it to operate in the forward direction under ambient conditions to provide cooling air to the tunnel under routine operation, and in the reverse direction at 400°C under emergency conditions in the event of a tunnel fire. The final aerodynamic and mechanical design was additionally required to generate no more than 80 db during reverse operation, to ensure members of the emergency service could still communicate in the event of a fire. The simulations were carried out using the open source code Open-Foam, within which the authors implemented a (Very) Large Eddy Simulation (V)LES based on an one-equation sub-grid scale SGS model to solve a transport equation for the modeled (sub-grid) turbulent kinetic energy. This improvement of the sub-grid turbulence model is here considered as a remedial strategy in VLES of high-Reynolds industrial flows able to tackle the otherwise insufficient resolution of turbulent spectrum. The VLES of the industrial fan permits to detect the flow features such as three-dimensional separation and secondary flows. Predicted noise emissions, in terms of sound pressure level spectra, are compared with experimental results, and found to agree within the uncertainty of the measurements.

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