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.
Download or read book Subsonic and Supersonic Jet Noise Calculations Using PSE and DNS written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-11 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: Noise radiated from a supersonic jet is computed using the Parabolized Stability Equations (PSE) method. The evolution of the instability waves inside the jet is computed using the PSE method and the noise radiated to the far field from these waves is calculated by solving the wave equation using the Fourier transform method. We performed the computations for a cold supersonic jet of Mach number 2.1 which is excited by disturbances with Strouhal numbers St=.2 and .4 and the azimuthal wavenumber m=l. Good agreement in the sound pressure level are observed between the computed and the measured (Troutt and McLaughlin 1980) results.Balakumar, P. and Owis, FaroukLangley Research CenterJET AIRCRAFT NOISE; SUPERSONIC JET FLOW; SUBSONIC FLOW; STABILITY; FAR FIELDS; WAVE EQUATIONS; FOURIER TRANSFORMATION; SOUND PRESSURE; COLD GAS; STROUHAL NUMBER; AZIMUTH
Download or read book The Generation and Radiation of Supersonic Jet Noise Future studies for definition of supersonic jet noise generation and reduction mechanisms written by and published by . This book was released on 1972 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Generation and Radiation of Supersonic Jet Noise written by Lockheed-Georgia Company and published by . This book was released on 1972 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 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 Aeroacoustics of Flight Vehicles written by Harvey H. Hubbard and published by . This book was released on 1991 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Noise Measurements in Supersonic Jets Treated with the Mach Wave Elimination Method written by Marco T. Debiasi and published by . This book was released on 1998 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of Computational Aeroacoustics Code for Jet Noise and Flow Prediction written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-20 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accurate prediction of jet fan and exhaust plume flow and noise generation and propagation is very important in developing advanced aircraft engines that will pass current and future noise regulations. In jet fan flows as well as exhaust plumes, two major sources of noise are present: large-scale, coherent instabilities and small-scale turbulent eddies. In previous work for the NASA Glenn Research Center, three strategies have been explored in an effort to computationally predict the noise radiation from supersonic jet exhaust plumes. In order from the least expensive computationally to the most expensive computationally, these are: 1) Linearized Euler equations (LEE). 2) Very Large Eddy Simulations (VLES). 3) Large Eddy Simulations (LES). The first method solves the linearized Euler equations (LEE). These equations are obtained by linearizing about a given mean flow and the neglecting viscous effects. In this way, the noise from large-scale instabilities can be found for a given mean flow. The linearized Euler equations are computationally inexpensive, and have produced good noise results for supersonic jets where the large-scale instability noise dominates, as well as for the tone noise from a jet engine blade row. However, these linear equations do not predict the absolute magnitude of the noise; instead, only the relative magnitude is predicted. Also, the predicted disturbances do not modify the mean flow, removing a physical mechanism by which the amplitude of the disturbance may be controlled. Recent research for isolated airfoils' indicates that this may not affect the solution greatly at low frequencies. The second method addresses some of the concerns raised by the LEE method. In this approach, called Very Large Eddy Simulation (VLES), the unsteady Reynolds averaged Navier-Stokes equations are solved directly using a high-accuracy computational aeroacoustics numerical scheme. With the addition of a two-equation turbulence model and the use of a relatively c
Download or read book Experimental Investigation of the Noise Reduction of Supersonic Exhaust Jets with Fluidic Inserts written by Russell Powers and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The noise produced by the supersonic, high temperature jets that exhaust from military aircraft is becoming a hazard to naval personnel and a disturbance to communities near military bases. Methods to reduce the noise produced from these jets in a practical full-scale environment are difficult. The development and analysis of distributed nozzle blowing for the reduction of radiated noise from supersonic jets is described. Model scale experiments of jets that simulate the exhaust jets from typical low-bypass ratio military jet aircraft engines during takeoff are performed. Fluidic inserts are created that use distributed blowing in the divergent section of the nozzle to simulate mechanical, hardwall corrugations, while having the advantage of being an active control method. This research focuses on model scale experiments to better understand the fluidic insert noise reduction method. Distributed blowing within the divergent section of the military-style convergent divergent nozzle alters the shock structure of the jet in addition to creating streamwise vorticity for the reduction of mixing noise. Enhancements to the fluidic insert design have been performed along with experiments over a large number of injection parameters and core jet conditions. Primarily military-style round nozzles have been used, with preliminary measurements of hardwall corrugations and fluidic inserts in rectangular nozzle geometries also performed. It has been shown that the noise reduction of the fluidic inserts is most heavily dependent upon the momentum flux ratio between the injector and core jet. Maximum reductions of approximately 5.5 dB OASPL have been observed with practical mass flow rates and injection pressures. The first measurements with fluidic inserts in the presence of a forward flight stream have been performed. Optimal noise reduction occurs at similar injector parameters in the presence of forward flight. Fluidic inserts in the presence of a forward flight stream were observed to reduce the peak mixing noise below the already reduced levels by nearly 4 dB OASPL and the broadband shock-associated noise by nearly 3 dB OASPL. Unsteady velocity measurements are used to complement acoustic results of jets with fluidic inserts. Measured axial turbulence intensities and mean axial velocity are examined to illuminate the differences in the flow field from jets with fluidic inserts. Comparisons of laser Doppler measurements with RANS CFD simulations are shown with good agreement. Analysis of the effect of spatial turbulence on the measured quantities is performed. Experimental model scale measurements of jets with and without fluidic inserts over a simulated carrier deck are presented. The model carrier environment consists of a ground plane of adjustable distance below the jet, and a simulated jet blast deflector similar to those found in practice. Measurements are performed with far-field microphones, near-field microphones, and unsteady pressure sensors. The constructive and destructive interference that results from the interaction of the direct and reflected sound waves is observed and compared with results from free jets. The noise reduction of fluidic inserts in a realistic carrier deck environment with steering of the ``quiet planes'' is examined. The overall sound pressure level in heat-simulated jets is reduced by 3-5 dB depending on the specific angle and ground plane height. Jets impinging upon a modeled jet blast deflector are tested in addition to jets solely in the presence of the carrier deck. Observed modifications to the acoustic field from the presence of the jet blast deflector include downstream acoustic shielding and low frequency augmentation. The region of maximum noise radiation for heat-simulated jets from nozzles with fluidic inserts impinging on the jet blast deflector is reduced in overall sound pressure level by 4-7 dB. This region includes areas where aircraft carrier personnel are located.
Download or read book The Generation and Radiation of Supersonic Jet Noise Jet flow measurement and analysis with special emphasis on remote sensing devices written by Lockheed-Georgia Company and published by . This book was released on 1972 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Commercial Supersonic Technology written by National Research Council and published by National Academies Press. This book was released on 2002-02-16 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-speed flight is a major technological challenge for both commercial and business aviation. As a first step in revitalizing efforts by the National Aeronautics and Space Administration (NASA) to achieve the technology objective of high-speed air travel, NASA requested the National Research Council (NRC) to conduct a study that would identify approaches for achieving breakthroughs in research and technology for commercial supersonic aircraft. Commercial Supersonic Technology documents the results of that effort. This report describes technical areas where ongoing work should be continued and new focused research initiated to enable operational deployment of an environmentally acceptable, economically viable commercial aircraft capable of sustained supersonic flight, including flight over land, at speeds up to approximately Mach 2 in the next 25 years or less.
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 Ground Measurements of the Shock wave Noise from Supersonic Bomber Airplanes in the Altitude Range from 30 000 to 50 000 Feet written by Domenic J. Maglieri and published by . This book was released on 1961 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Simulations of the Flow Generated by Fluidic Inserts for Supersonic Jet Noise Reduction Based on Steady RANS Simulations written by Matthew Kapusta and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The investigation of military jet noise prediction and reduction is an ongoing activity. Supersonic military jets radiate higher noise levels than commercial aircraft and are not subject to noise requirements. The noise generating mechanisms for high-speed jets are not entirely understood, making it difficult to set strict noise standards similar to those imposed for commercial aircraft. However, many noise reduction techniques have been applied to attempt to alleviate environmental and health concerns. Little success has been achieved to date for noise reduction of exhaust jets on supersonic tactical aircraft.A newly developed method involves a system that generates fluidic inserts in a supersonic nozzle flow to produce noise reduction. Numerical simulations have been performed for a military-style basline nozzle and with the noise reduction method of fluidic inserts used at a design Mach number of 1.65 and at various off design conditions. The purpose of the current numerical study is to provide insight for the flow field generated by the fluidic inserts used to reduce supersonic jet noise. The supersonic jet simulations are based on the use of high fidelity meshes combined with advanced CFD technology. Steady Reynolds-averaged Navier-Stokes (RANS) simulations are used to predict the flow field. Noise measurements have been performed experimentally and the results from the numerical simulations provide a correlation between aerodynamic properties and the corresponding noise reduction. The complex nozzle geometry is modeled using both an unstructured mesh and a multiblock structured mesh. The grids are generated by ANSYS ICEM and Gridgen respectively. The numerical simulations are performed using ANSYS CFX and Wind-US. The simulations with Wind-US use the Spalart-Allmaras turbulence model, while the simulations with ANSYS CFX use the Menter SST turbulence model. The results from the two flow solvers are compared and provide good agreement. The objective is to simulate a military-style nozzle, which resembles engines of the GE F404 family, with fluidic inserts. The purpose of the fluidic inserts is to alter the flow field similar to that of a hard wall corrugation in order to reduce components of noise radiation. The addition of the fluidic inserts increases the complexity of the flow field for the supersonic jet. The numerical simulations performed help to better distinguish the effects on the flow field due to the fluidic inserts. Preliminary work has been performed on a simpler geometry to provide further insight to the effect of the fluidic inserts on the supersonic jet flow field. These simulations are performed by fluid injection into a supersonic freestream over a flat plate. All numerical simulations used a freestream Mach number of 1.5. The numerical simulations used a wide range of pressure ratios for injecting the fluid into the supersonic freestream. By changing the pressure ratio of the fluid injection, the deflection of the freestream flow was better understood. Simulations on a full three dimensional nozzle with fluidic inserts were performed with conditions based on the preliminary studies. Parameters such as total pressure and total temperature provide a representation of the fluidic insert shape. Other integrated flow properties at the nozzle exit such as streamwise vorticity and pressure differential were used to correlate with the noise reduction seen in the experiments.
Download or read book High Speed Research Noise Prediction Code User s and Theoretical Manual written by Robert Golub and published by BiblioGov. This book was released on 2013-07 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes a computer program, HSRNOISE, that predicts noise levels for a supersonic aircraft powered by mixed flow turbofan engines with rectangular mixer-ejector nozzles. It fully documents the noise prediction algorithms, provides instructions for executing the HSRNOISE code, and provides predicted noise levels for the High Speed Research (HSR) program Technology Concept (TC) aircraft. The component source noise prediction algorithms were developed jointly by Boeing, General Electric Aircraft Engines (GEAE), NASA and Pratt & Whitney during the course of the NASA HSR program. Modern Technologies Corporation developed an alternative mixer ejector jet noise prediction method under contract to GEAE that has also been incorporated into the HSRNOISE prediction code. Algorithms for determining propagation effects and calculating noise metrics were taken from the NASA Aircraft Noise Prediction Program.
