Supersonic Jet Noise: an Investigation into Noise Generation Mechanisms using Large Eddy Simulation and High-Resolution PIV Data

2017 ◽  
Author(s):  
Anton P. Markesteijn ◽  
Vasily Semiletov ◽  
Sergey A. Karabasov ◽  
Dominic J. Tan ◽  
Marcus Wong ◽  
...  
Keyword(s):  
High Resolution ◽  
Large Eddy Simulation ◽  
Supersonic Jet ◽  
Jet Noise ◽  
Noise Generation ◽  
Supersonic Jet Noise ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Generation Mechanisms

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.

scholarly journals Vertically nested LES for high-resolution simulation of the surface layer in PALM (version 5.0)

2019 ◽  
Vol 12 (6) ◽  
pp. 2523-2538 ◽  
Author(s):  
Sadiq Huq ◽  
Frederik De Roo ◽  
Siegfried Raasch ◽  
Matthias Mauder
Keyword(s):  
Boundary Layer ◽  
Surface Layer ◽  
High Resolution ◽  
Large Eddy Simulation ◽  
Grid Resolution ◽  
Computational Power ◽  
Fine Grid ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Nesting Algorithm

Abstract. Large-eddy simulation (LES) has become a well-established tool in the atmospheric boundary layer research community to study turbulence. It allows three-dimensional realizations of the turbulent fields, which large-scale models and most experimental studies cannot yield. To resolve the largest eddies in the mixed layer, a moderate grid resolution in the range of 10 to 100 m is often sufficient, and these simulations can be run on a computing cluster with a few hundred processors or even on a workstation for simple configurations. The desired resolution is usually limited by the computational resources. However, to compare with tower measurements of turbulence and exchange fluxes in the surface layer, a much higher resolution is required. In spite of the growth in computational power, a high-resolution LES of the surface layer is often not feasible: to fully resolve the energy-containing eddies near the surface, a grid spacing of O(1 m) is required. One way to tackle this problem is to employ a vertical grid nesting technique, in which the surface is simulated at the necessary fine grid resolution, and it is coupled with a standard, coarse, LES that resolves the turbulence in the whole boundary layer. We modified the LES model PALM (Parallelized Large-eddy simulation Model) and implemented a two-way nesting technique, with coupling in both directions between the coarse and the fine grid. The coupling algorithm has to ensure correct boundary conditions for the fine grid. Our nesting algorithm is realized by modifying the standard third-order Runge–Kutta time stepping to allow communication of data between the two grids. The two grids are concurrently advanced in time while ensuring that the sum of resolved and sub-grid-scale kinetic energy is conserved. We design a validation test and show that the temporally averaged profiles from the fine grid agree well compared to the reference simulation with high resolution in the entire domain. The overall performance and scalability of the nesting algorithm is found to be satisfactory. Our nesting results in more than 80 % savings in computational power for 5 times higher resolution in each direction in the surface layer.

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