Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781721026104
Category :
Languages : en
Pages : 86
Book Description
The problem of broadband noise generated by turbulence impinging on a downstream blade row is examined from a theoretical viewpoint. Equations are derived for sound power spectra in terms of 3 dimensional wavenumber spectra of the turbulence. Particular attention is given to issues of turbulence inhomogeneity associated with the near field of the rotor and variations through boundary layers. Lean and sweep of the rotor or stator cascade are also handled rigorously with a full derivation of the relevant geometry and definitions of lean and sweep angles. Use of the general theory is illustrated by 2 simple theoretical spectra for homogeneous turbulence. Limited comparisons are made with data from model fans designed by Pratt & Whitney, Allison, and Boeing. Parametric studies for stator noise are presented showing trends with Mach number, vane count, turbulence scale and intensity, lean, and sweep. Two conventions are presented to define lean and sweep. In the "cascade system" lean is a rotation out of its plane and sweep is a rotation of the airfoil in its plane. In the "duct system" lean is the leading edge angle viewing the fan from the front (along the fan axis) and sweep is the angle viewing the fan from the side (, perpendicular to the axis). It is shown that the governing parameter is sweep in the plane of the airfoil (which reduces the chordwise component of Mach number). Lean (out of the plane of the airfoil) has little effect. Rotor noise predictions are compared with duct turbulence/rotor interaction noise data from Boeing and variations, including blade tip sweep and turbulence axial and transverse scales are explored.Hanson, Donald B.Glenn Research CenterINTERACTIONAL AERODYNAMICS; ROTORS; STATORS; CASCADE FLOW; TURBOFAN ENGINES; HOMOGENEOUS TURBULENCE; NOISE PREDICTION; ENGINE NOISE; POWER SPECTRA; LEADING EDGES; DUCTS; BROADBAND; BLADE TIPS; AIRFOILS; BOUNDARY LAYERS; MACH NUMBER; SWEEP ANGLE
Theory for Broadband Noise of Rotor and Stator Cascades with Inhomogeneous Inflow Turbulence Including Effects of Lean and Sweep
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781721026104
Category :
Languages : en
Pages : 86
Book Description
The problem of broadband noise generated by turbulence impinging on a downstream blade row is examined from a theoretical viewpoint. Equations are derived for sound power spectra in terms of 3 dimensional wavenumber spectra of the turbulence. Particular attention is given to issues of turbulence inhomogeneity associated with the near field of the rotor and variations through boundary layers. Lean and sweep of the rotor or stator cascade are also handled rigorously with a full derivation of the relevant geometry and definitions of lean and sweep angles. Use of the general theory is illustrated by 2 simple theoretical spectra for homogeneous turbulence. Limited comparisons are made with data from model fans designed by Pratt & Whitney, Allison, and Boeing. Parametric studies for stator noise are presented showing trends with Mach number, vane count, turbulence scale and intensity, lean, and sweep. Two conventions are presented to define lean and sweep. In the "cascade system" lean is a rotation out of its plane and sweep is a rotation of the airfoil in its plane. In the "duct system" lean is the leading edge angle viewing the fan from the front (along the fan axis) and sweep is the angle viewing the fan from the side (, perpendicular to the axis). It is shown that the governing parameter is sweep in the plane of the airfoil (which reduces the chordwise component of Mach number). Lean (out of the plane of the airfoil) has little effect. Rotor noise predictions are compared with duct turbulence/rotor interaction noise data from Boeing and variations, including blade tip sweep and turbulence axial and transverse scales are explored.Hanson, Donald B.Glenn Research CenterINTERACTIONAL AERODYNAMICS; ROTORS; STATORS; CASCADE FLOW; TURBOFAN ENGINES; HOMOGENEOUS TURBULENCE; NOISE PREDICTION; ENGINE NOISE; POWER SPECTRA; LEADING EDGES; DUCTS; BROADBAND; BLADE TIPS; AIRFOILS; BOUNDARY LAYERS; MACH NUMBER; SWEEP ANGLE
Publisher: Createspace Independent Publishing Platform
ISBN: 9781721026104
Category :
Languages : en
Pages : 86
Book Description
The problem of broadband noise generated by turbulence impinging on a downstream blade row is examined from a theoretical viewpoint. Equations are derived for sound power spectra in terms of 3 dimensional wavenumber spectra of the turbulence. Particular attention is given to issues of turbulence inhomogeneity associated with the near field of the rotor and variations through boundary layers. Lean and sweep of the rotor or stator cascade are also handled rigorously with a full derivation of the relevant geometry and definitions of lean and sweep angles. Use of the general theory is illustrated by 2 simple theoretical spectra for homogeneous turbulence. Limited comparisons are made with data from model fans designed by Pratt & Whitney, Allison, and Boeing. Parametric studies for stator noise are presented showing trends with Mach number, vane count, turbulence scale and intensity, lean, and sweep. Two conventions are presented to define lean and sweep. In the "cascade system" lean is a rotation out of its plane and sweep is a rotation of the airfoil in its plane. In the "duct system" lean is the leading edge angle viewing the fan from the front (along the fan axis) and sweep is the angle viewing the fan from the side (, perpendicular to the axis). It is shown that the governing parameter is sweep in the plane of the airfoil (which reduces the chordwise component of Mach number). Lean (out of the plane of the airfoil) has little effect. Rotor noise predictions are compared with duct turbulence/rotor interaction noise data from Boeing and variations, including blade tip sweep and turbulence axial and transverse scales are explored.Hanson, Donald B.Glenn Research CenterINTERACTIONAL AERODYNAMICS; ROTORS; STATORS; CASCADE FLOW; TURBOFAN ENGINES; HOMOGENEOUS TURBULENCE; NOISE PREDICTION; ENGINE NOISE; POWER SPECTRA; LEADING EDGES; DUCTS; BROADBAND; BLADE TIPS; AIRFOILS; BOUNDARY LAYERS; MACH NUMBER; SWEEP ANGLE
Theory for Broadband Noise of Rotor and Stator Cascades with Inhomogeneous Inflow Turbulence Including Effects of Lean and Sweep
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 92
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 92
Book Description
Broadband Noise of Fans - With Unsteady Coupling Theory to Account for Rotor and Stator Reflection/Transmission Effects
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 98
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 98
Book Description
Monthly Catalog of United States Government Publications
Author:
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 836
Book Description
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 836
Book Description
The Journal of the Acoustical Society of America
Author: Acoustical Society of America
Publisher:
ISBN:
Category : Acoustical engineering
Languages : en
Pages : 1360
Book Description
Publisher:
ISBN:
Category : Acoustical engineering
Languages : en
Pages : 1360
Book Description
AIAA Journal
Author: American Institute of Aeronautics and Astronautics
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1024
Book Description
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1024
Book Description
Analytical Assessment of Stator Sweep and Lean in Reducing Rotor-stator Tone Noise
Author: E. Envia
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Aeroacoustics of Flight Vehicles
Author: Harvey H. Hubbard
Publisher:
ISBN:
Category : Aerodynamic noise
Languages : en
Pages : 620
Book Description
Publisher:
ISBN:
Category : Aerodynamic noise
Languages : en
Pages : 620
Book Description
Acoustic Benefits of Stator Sweep and Lean for a High Tip Speed Fan
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 26
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 26
Book Description
Unsteady Aerodynamics, Aeroacoustics and Aeroelasticity of Turbomachines
Author: Kenneth C. Hall
Publisher: Springer Science & Business Media
ISBN: 1402046057
Category : Technology & Engineering
Languages : en
Pages : 605
Book Description
This textbook is a collection of technical papers that were presented at the 10th International Symposium on Unsteady Aerodynamics, Aeroacoustics, and Aeroelasticity of Turbomachines held September 8-11, 2003 at Duke University in Durham, North Carolina. The papers represent the latest in state of the art research in the areas of aeroacoustics, aerothermodynamics, computational methods, experimental testing related to flow instabilities, flutter, forced response, multistage, and rotor-stator effects for turbomachinery.
Publisher: Springer Science & Business Media
ISBN: 1402046057
Category : Technology & Engineering
Languages : en
Pages : 605
Book Description
This textbook is a collection of technical papers that were presented at the 10th International Symposium on Unsteady Aerodynamics, Aeroacoustics, and Aeroelasticity of Turbomachines held September 8-11, 2003 at Duke University in Durham, North Carolina. The papers represent the latest in state of the art research in the areas of aeroacoustics, aerothermodynamics, computational methods, experimental testing related to flow instabilities, flutter, forced response, multistage, and rotor-stator effects for turbomachinery.