Download or read book Prediction of Flow and Acoustic Fields of a Supersonic Jet written by S. H. Shih and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book On the Prediction of the Near Field Noise of Supersonic Jets written by J. B. Ollerhead and published by . This book was released on 1967 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Preliminary Study of Acoustic Prediction Technology Based on Detached Eddy Simulations for Supersonic Jets Impinging on Flat Plates written by Yuvraj Dewan and published by . This book was released on 2013 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: "An application of an existing industry tool to study supersonic jets impinging on flat plates is shown. This industry tool is the commercially available CFD package ANSYS FLUENT. The supersonic jet studied is perfectly expanded with a Mach number of 1.5, and it impinges on a flat surface 4 nozzle throat diameters from the jet exit. All turbulence modeling is done using a hybrid RANS/LES technique known as Delayed Detached Eddy Simulation (DDES). A transient solution is calculated using the pressure-based coupled solver formulation with the second-order bounded central-upwind spatial discretization and second-order implicit time marching scheme. Flow features like the stagnation bubble, wall jet and feedback mechanism were studied using countour plots. An examination was also done into the mean flow fields of the jet core. The acoustics of the case were studied using two different techniques, direct measurements and the use of a acoustics source surface method. Using limited computational power, reasonable agreement between simulation and experimental data was found for the flow-field and acoustics. Thus, it was demonstrated that ANSYS FLUENT can be used for this problem to provide good preliminary results in an industry setting with limited computational power"--Leaf vi.

Download or read book The Effects of Vane type Tabs on Flow and Acoustic Fields of Supersonic Jet written by Mohammed K. Ibrahim and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Generation and Radiation of Supersonic Jet Noise Progress toward a unified theory of jet engine noise written by Lockheed-Georgia Company and published by . This book was released on 1972 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Simulation of Supersonic Jet Noise with the Adaptation of Overflow Cfd Code and Kirchhoff Surface Integral written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-19 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: An acoustic prediction capability for supersonic axisymmetric jets was developed on the basis of OVERFLOW Navier-Stokes CFD (Computational Fluid Dynamics) code of NASA Langley Research Center. Reynolds-averaged turbulent stresses in the flow field are modeled with the aid of Spalart-Allmaras one-equation turbulence model. Appropriate acoustic and outflow boundary conditions were implemented to compute time-dependent acoustic pressure in the nonlinear source-field. Based on the specification of acoustic pressure, its temporal and normal derivatives on the Kirchhoff surface, the near-field and the far-field sound pressure levels are computed via Kirchhoff surface integral, with the Kirchhoff surface chosen to enclose the nonlinear sound source region described by the CFD code. The methods are validated by a comparison of the predictions of sound pressure levels with the available data for an axisymmetric turbulent supersonic (Mach 2) perfectly expanded jet. Kandula, Max and Caimi, Raoul and Steinrock, T. (Technical Monitor) Kennedy Space Center NASA/TM-2001-210263, NAS 1.15:210263

Download or read book Simulation of Supersonic Jet Noise with the Adaptation of Overflow Cfd Code and Kirchhoff Surface Integral written by Max Kandula and published by BiblioGov. This book was released on 2013-08 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: An acoustic prediction capability for supersonic axisymmetric jets was developed on the basis of OVERFLOW Navier-Stokes CFD (Computational Fluid Dynamics) code of NASA Langley Research Center. Reynolds-averaged turbulent stresses in the flow field are modeled with the aid of Spalart-Allmaras one-equation turbulence model. Appropriate acoustic and outflow boundary conditions were implemented to compute time-dependent acoustic pressure in the nonlinear source-field. Based on the specification of acoustic pressure, its temporal and normal derivatives on the Kirchhoff surface, the near-field and the far-field sound pressure levels are computed via Kirchhoff surface integral, with the Kirchhoff surface chosen to enclose the nonlinear sound source region described by the CFD code. The methods are validated by a comparison of the predictions of sound pressure levels with the available data for an axisymmetric turbulent supersonic (Mach 2) perfectly expanded jet.

Download or read book High Performance Computing written by Heike Jagode and published by Springer Nature. This book was released on 2020-10-19 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the refereed post-conference proceedings of 10 workshops held at the 35th International ISC High Performance 2020 Conference, in Frankfurt, Germany, in June 2020: First Workshop on Compiler-assisted Correctness Checking and Performance Optimization for HPC (C3PO); First International Workshop on the Application of Machine Learning Techniques to Computational Fluid Dynamics Simulations and Analysis (CFDML); HPC I/O in the Data Center Workshop (HPC-IODC); First Workshop \Machine Learning on HPC Systems" (MLHPCS); First International Workshop on Monitoring and Data Analytics (MODA); 15th Workshop on Virtualization in High-Performance Cloud Computing (VHPC). The 25 full papers included in this volume were carefully reviewed and selected. They cover all aspects of research, development, and application of large-scale, high performance experimental and commercial systems. Topics include high-performance computing (HPC), computer architecture and hardware, programming models, system software, performance analysis and modeling, compiler analysis and optimization techniques, software sustainability, scientific applications, deep learning.

Download or read book Supersonic Jet Noise Reductions Predicted with Increased Jet Spreading Rate written by and published by . This book was released on 1995 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Zonal Approach for Prediction of Jet Noise written by S. H. Shih and published by . This book was released on 1995 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Generation and Radiation of Supersonic Jet Noise Summary of supersonic jet noise studies written by and published by . This book was released on 1972 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Three dimensional Numerical Simulation of a Supersonic Under expanded Rectangular Jet written by Ibraheem M. A. Al-Qadi and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: A three-dimensional numerical simulation of the unsteady flow in an under-expanded supersonic rectangular jet has been conducted for the purpose of investigating and analyzing the production and propagation of jet noise. The compressible three-dimensional Navier-Stokes equations are solved using high-order spatial and temporal differencing schemes. The solution method applies linear and nonlinear filtering schemes to produce oscillation-free shocks and discontinuities while minimizing dissipation effects in smooth regions. The solution method also applies nonreflecting boundary conditions to minimize reflections. Characteristic boundary conditions are implemented at the upstream and far-field boundaries and an absorbing buffer zone is added at the outflow boundary. OpenMP shared- memory model was utilized to parallelize the simulation and good parallel performance was achieved. The code was used to conduct a time dependent numerical simulation of an under-expanded supersonic rectangular jet. A comprehensive database of the simulation was generated. The results of the simulation were validated against experimental measurements and show very good agreement. The simulation is shown to resolve critical unsteady flow features of the jet such as vortex shedding, shock-cell structure, shock shear-layer interaction, flapping, and axis-switching. Visualization of the unsteady flow and analysis of the turbulent flow-field shows that the location of axis-switching is immediately downstream of the fourth shock. It is also observed that the location of the dominant screech source is at the third shock. Two-point space-time correlations demonstrate that the convection velocities in the jet shear layer are highly modulated by the presence of shock waves. Spectral analysis show that the simulation predicts, with good accuracy, screech modes frequencies, wavelengths, phase, and amplitudes. Analysis inside the jet shear layer and in the acoustic near-field reveal exact correspondence in frequency and phase between the inner and the outer parts of the screech loop. The simulation also predicts the complex pattern of the near acoustic field associated with screech. The current simulation represents the first successful three- dimensional numerical simulation of an under-expanded supersonic rectangular jet. It also represents a significant contribution towards accurate prediction of noise production and far-field radiation in supersonic jets. The computational tools developed in this study can be used to investigate a wide range of problems related to unsteady flows and aeroacoustics.

Download or read book The Generation and Radiation of Supersonic Jet Noise Theory of turbulence generated jet noise noise radiation from upstream sources and combustion noise written by and published by . This book was released on 1972 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Predictions of Supersonic Jet Mixing and Shock Associated Noise Compared with Measured Far Field Data written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-22 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt: Codes for predicting supersonic jet mixing and broadband shock-associated noise were assessed using a database containing noise measurements of a jet issuing from a convergent nozzle. Two types of codes were used to make predictions. Fast running codes containing empirical models were used to compute both the mixing noise component and the shock-associated noise component of the jet noise spectrum. One Reynolds-averaged, Navier-Stokes-based code was used to compute only the shock-associated noise. To enable the comparisons of the predicted component spectra with data, the measured total jet noise spectra were separated into mixing noise and shock-associated noise components. Comparisons were made for 1/3-octave spectra and some power spectral densities using data from jets operating at 24 conditions covering essentially 6 fully expanded Mach numbers with 4 total temperature ratios. Dahl, Milo D. Glenn Research Center JET MIXING FLOW; JET AIRCRAFT NOISE; SUPERSONIC JET FLOW; AERODYNAMIC NOISE; NOISE MEASUREMENT; NOISE SPECTRA; FLUID JETS; MACH NUMBER; PREDICTIONS; SHOCK WAVES; TEMPERATURE RATIO

Download or read book A Review of Instability and Noise Propagation in Supersonic Flows written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-29 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Originally analytical and numerical models were to be developed for noise production in supersonic jets, wakes and free shear layers. While the effort was concentrated initially on these aspects, other topics were also pursued, most were of interest to the Jet Noise Group of the Aeroacoustics Branch. An overview is given of subjects reviewed and the investigations that were carried out. A significant effort was devoted to numerically predicting the flow field of a turbulent supersonic wall jet. This information is necessary for computing the pressure in the far field. The wall jet was selected because it represents a generic flow that can be associated with plug nozzle in supersonic engines. It combines the characteristic of a boundary layer with that of a free shear flow. The spatially evolving flow obtained using Dash's code would form the input for the stability analysis program. This analysis would determine the large scale instability wave within the flow. The far field pressure can be computed from the shape of the evolving large scale structure by asymptotic methods. Flow characteristics obtained from a program that analyses the turbulent downstream supersonic flow in a nozzle are described and compared with experimental results. Daudpota, Q. Isa and Lakin, William D. Unspecified Center NAG1-881...

Download or read book Supersonic Jet Exhaust Noise Investigation Volume III Computer User s Manual for Aero Acoustic Predictions written by David R. Ferguson and published by . This book was released on 1976 with total page 683 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report gives a detailed description of aerodynamic (Shock-free/Shocked flow) and acoustic turbulent mixing computer prediction programs developed by the General Electric Company for subsonic and supersonic simple exhaust jets. In addition to giving detailed descriptions of the aeroacoustic formulations and discussions of computer manual instructions for operating the program, extensive theory/data comparisons are given, as well as computer program listings and sample test cases. (Author).

Download or read book The Development of a Fast Method for the Calculation of Noise from Supersonic Jets written by Andrew Thomas Merck and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of a high-speed jet noise prediction method that is significantly less computationally expensive than previous computationally-based methods and which provides a simple user interface is described. Several sets of far-field spectral density experimental data are decomposed into their large-scale turbulence component and the corresponding near-field wavenumber spectra are calculated. A wavepacket model is used to characterize the near-field wavenumber spectrum at the surface of the jet flow, and the wavepacket properties given by the near-field spectra at various frequencies and operating conditions are found using Gaussian fits. A large database is compiled from the wavepacket properties for a range of operating conditions, and the far-field jet noise is predicted using a mathematical model that combines the wavepacket model and existing models. Comparison of the wavepacket-model far-field supersonic jet noise predictions and experimental measurements are made, and the results demonstrate that the wavepacket-model results in accurate noise predictions.