Wall-resolved Large Eddy Simulation of a highlift airfoil: detailed flow analysis and noise generation study

2014 ◽  
Author(s):  
Marc Terracol ◽  
Eric Manoha
Keyword(s):  
Large Eddy Simulation ◽  
Flow Analysis ◽  
Noise Generation ◽  
Eddy Simulation ◽  
Large Eddy

RANS and Large Eddy Simulation of Internal Combustion Engine Flows—A Comparative Study

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Xiaofeng Yang ◽  
Saurabh Gupta ◽  
Tang-Wei Kuo ◽  
Venkatesh Gopalakrishnan
Keyword(s):  
Large Eddy Simulation ◽  
High Speed ◽  
Combustion Engine ◽  
Flow Analysis ◽  
Partial Geometry ◽  
Computational Domain ◽  
Mean Flow ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Rans Simulations

A comparative cold flow analysis between Reynolds-averaged Navier–Stokes (RANS) and large eddy simulation (LES) cycle-averaged velocity and turbulence predictions is carried out for a single cylinder engine with a transparent combustion chamber (TCC) under motored conditions using high-speed particle image velocimetry (PIV) measurements as the reference data. Simulations are done using a commercial computationally fluid dynamics (CFD) code CONVERGE with the implementation of standard k-ε and RNG k-ε turbulent models for RANS and a one-equation eddy viscosity model for LES. The following aspects are analyzed in this study: The effects of computational domain geometry (with or without intake and exhaust plenums) on mean flow and turbulence predictions for both LES and RANS simulations. And comparison of LES versus RANS simulations in terms of their capability to predict mean flow and turbulence. Both RANS and LES full and partial geometry simulations are able to capture the overall mean flow trends qualitatively; but the intake jet structure, velocity magnitudes, turbulence magnitudes, and its distribution are more accurately predicted by LES full geometry simulations. The guideline therefore for CFD engineers is that RANS partial geometry simulations (computationally least expensive) with a RNG k-ε turbulent model and one cycle or more are good enough for capturing overall qualitative flow trends for the engineering applications. However, if one is interested in getting reasonably accurate estimates of velocity magnitudes, flow structures, turbulence magnitudes, and its distribution, they must resort to LES simulations. Furthermore, to get the most accurate turbulence distributions, one must consider running LES full geometry simulations.

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.

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.

Sign in / Sign up

Export Citation Format

Share Document