Author: Anthony L. Laganelli
Publisher:
ISBN:
Category : Ballistic missiles
Languages : en
Pages : 184
Book Description
An experimental program was conducted at the AEDC von Karman facility, Tunnels A and B, in which acoustic pressure fluctuation data were acquired on a 7 degree half-cone-angle model featuring a control surface. The objective was to define the aeroacoustic environment applicable to re-entry vibration response analysis for both ballistic and maneuvering vehicles. Wind tunnel measurements were obtained at Mach 4 and 8 for several values of freestream Reynolds number and model angle of attack. Stationary zones of laminar, transitional, and turbulent flow over the model were achieved. Acoustic data were reduced to rms fluctuating pressure, and power and cross-power spectral densities. Results were normalized using local boundary layer parameters for comparison with previous high speed measurements. The present study re-examined the aeroacoustic environment prediction capability relative to compressible flow conditions. Moreover, boundary layer characteristic lengths and velocities were reviewed in order to develop normalization procedures required for development of appropriate aeroacoustic scaling laws. It was determined that fluctuating pressure characteristics described by incompressible theory as well as empirical correlations could be modified to a compressible state through a transformation function. In this manner, compressible data were transformed to the incompressible plane where direct use of more tractable prediction techniques are available for engineering design analyses.
Prediction of the Pressure Fluctuations Associated with Maneuvering Reentry Weapons
Author: Anthony L. Laganelli
Publisher:
ISBN:
Category : Ballistic missiles
Languages : en
Pages : 184
Book Description
An experimental program was conducted at the AEDC von Karman facility, Tunnels A and B, in which acoustic pressure fluctuation data were acquired on a 7 degree half-cone-angle model featuring a control surface. The objective was to define the aeroacoustic environment applicable to re-entry vibration response analysis for both ballistic and maneuvering vehicles. Wind tunnel measurements were obtained at Mach 4 and 8 for several values of freestream Reynolds number and model angle of attack. Stationary zones of laminar, transitional, and turbulent flow over the model were achieved. Acoustic data were reduced to rms fluctuating pressure, and power and cross-power spectral densities. Results were normalized using local boundary layer parameters for comparison with previous high speed measurements. The present study re-examined the aeroacoustic environment prediction capability relative to compressible flow conditions. Moreover, boundary layer characteristic lengths and velocities were reviewed in order to develop normalization procedures required for development of appropriate aeroacoustic scaling laws. It was determined that fluctuating pressure characteristics described by incompressible theory as well as empirical correlations could be modified to a compressible state through a transformation function. In this manner, compressible data were transformed to the incompressible plane where direct use of more tractable prediction techniques are available for engineering design analyses.
Publisher:
ISBN:
Category : Ballistic missiles
Languages : en
Pages : 184
Book Description
An experimental program was conducted at the AEDC von Karman facility, Tunnels A and B, in which acoustic pressure fluctuation data were acquired on a 7 degree half-cone-angle model featuring a control surface. The objective was to define the aeroacoustic environment applicable to re-entry vibration response analysis for both ballistic and maneuvering vehicles. Wind tunnel measurements were obtained at Mach 4 and 8 for several values of freestream Reynolds number and model angle of attack. Stationary zones of laminar, transitional, and turbulent flow over the model were achieved. Acoustic data were reduced to rms fluctuating pressure, and power and cross-power spectral densities. Results were normalized using local boundary layer parameters for comparison with previous high speed measurements. The present study re-examined the aeroacoustic environment prediction capability relative to compressible flow conditions. Moreover, boundary layer characteristic lengths and velocities were reviewed in order to develop normalization procedures required for development of appropriate aeroacoustic scaling laws. It was determined that fluctuating pressure characteristics described by incompressible theory as well as empirical correlations could be modified to a compressible state through a transformation function. In this manner, compressible data were transformed to the incompressible plane where direct use of more tractable prediction techniques are available for engineering design analyses.
Prediction of Pressure Fuctuations Associated with Maneuvering Re-entry Weapons
Author: Anthony L. Laganelli
Publisher:
ISBN:
Category : Guided missiles
Languages : en
Pages : 244
Book Description
An experimental program was conducted at the AEDC vonKarman facility, Tunnels A and B, in which acoustic pressure fluctuation data were acquired on a 7 degree half-cone-angle model featuring a control surface. The objective was to define the aeroacoustic environment applicable to re-entry vibration response analysis for both ballistic and maneuvering vehicles. Wind tunnel measurements were obtained at Mach 4 and 8 for several values of freestream Reynolds number and model angle of attack. Stationary zones of laminar, transitional, and turbulent flow over the model were achieved. Acoustic data were reduced to rms fluctuating pressure, and power and cross-power spectral densities. Results were normalized using local boundary layer parameters for comparison with previous high speed measurements. The present study re-examined the aeroacoustic environment prediction capability relative to compressible flow conditions. Moreover, boundary layer characteristic lengths and velocities were reviewed in order to develop normalization procedures required for development of appropriate aeroacoustic scaling laws. It was determined that fluctuating pressure characteristics described by incompressible theory as well as empirical correlations could be modified to a compressible state through a transformation function. In this manner, compressible data were transformed to the incompressible plane where direct use of more tractable prediction techniques are available for engineering design analyses.
Publisher:
ISBN:
Category : Guided missiles
Languages : en
Pages : 244
Book Description
An experimental program was conducted at the AEDC vonKarman facility, Tunnels A and B, in which acoustic pressure fluctuation data were acquired on a 7 degree half-cone-angle model featuring a control surface. The objective was to define the aeroacoustic environment applicable to re-entry vibration response analysis for both ballistic and maneuvering vehicles. Wind tunnel measurements were obtained at Mach 4 and 8 for several values of freestream Reynolds number and model angle of attack. Stationary zones of laminar, transitional, and turbulent flow over the model were achieved. Acoustic data were reduced to rms fluctuating pressure, and power and cross-power spectral densities. Results were normalized using local boundary layer parameters for comparison with previous high speed measurements. The present study re-examined the aeroacoustic environment prediction capability relative to compressible flow conditions. Moreover, boundary layer characteristic lengths and velocities were reviewed in order to develop normalization procedures required for development of appropriate aeroacoustic scaling laws. It was determined that fluctuating pressure characteristics described by incompressible theory as well as empirical correlations could be modified to a compressible state through a transformation function. In this manner, compressible data were transformed to the incompressible plane where direct use of more tractable prediction techniques are available for engineering design analyses.
Technical Abstract Bulletin
Author:
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 780
Book Description
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 780
Book Description
Notices of Changes in Classification, Distribution and Availability
Author:
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 372
Book Description
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 372
Book Description
Fluctuating Pressure Loads for Hypersonic Vehicle Structures
Author: Henry G. Lew
Publisher:
ISBN:
Category : Acoustic radiation pressure
Languages : en
Pages : 80
Book Description
This investigation was conducted to determine the ability to predict acoustic loads on supersonic/hypersonic structures with attached and separated flows. These techniques, which are based on laws governing boundary layer flow and shock physics, provide scaling parameters to extrapolate ground test results to flight conditions and can be used for the design process. It was determined that efficient, thin aerodynamic control surfaces generally produce weak shock/ boundary layers interactions where the rms pressure levels are not significantly augmented over attached flow levels. The exception to these findings include: (1) corner flow (inlet and stabilizers); (2) bow shock interaction (inlet and stabilizer); and (3) shock on shock/boundary layer (cowl/inlet, bow shock/inlet, and bow/inlet/cowl). Other potential interactions that may cause problems have been identified as: (1) axial offset (non-common intersection of two planes); (2) shock interaction with laminar boundary layers; (3) angle of attack effects; and (4) viscous approach flow along ramp leading to the inlet. An experimental program is recommended to address these issues; in particular for M> 3 where acoustic data does not exist. These experiments should be conducted in a facility that allows for preliminary test runs to ensure desired results. The WRDC Mach 3 and Mach 12 facilities are recommended for a Phase II investigation. Results of the Phase I and II efforts will provide the ability to design structures subject to complex flow interactions such as the National AeroSpace Plane.
Publisher:
ISBN:
Category : Acoustic radiation pressure
Languages : en
Pages : 80
Book Description
This investigation was conducted to determine the ability to predict acoustic loads on supersonic/hypersonic structures with attached and separated flows. These techniques, which are based on laws governing boundary layer flow and shock physics, provide scaling parameters to extrapolate ground test results to flight conditions and can be used for the design process. It was determined that efficient, thin aerodynamic control surfaces generally produce weak shock/ boundary layers interactions where the rms pressure levels are not significantly augmented over attached flow levels. The exception to these findings include: (1) corner flow (inlet and stabilizers); (2) bow shock interaction (inlet and stabilizer); and (3) shock on shock/boundary layer (cowl/inlet, bow shock/inlet, and bow/inlet/cowl). Other potential interactions that may cause problems have been identified as: (1) axial offset (non-common intersection of two planes); (2) shock interaction with laminar boundary layers; (3) angle of attack effects; and (4) viscous approach flow along ramp leading to the inlet. An experimental program is recommended to address these issues; in particular for M> 3 where acoustic data does not exist. These experiments should be conducted in a facility that allows for preliminary test runs to ensure desired results. The WRDC Mach 3 and Mach 12 facilities are recommended for a Phase II investigation. Results of the Phase I and II efforts will provide the ability to design structures subject to complex flow interactions such as the National AeroSpace Plane.
A Collection of Technical Papers: Structural dynamics II
Author:
Publisher:
ISBN:
Category : Aerodynamics
Languages : en
Pages : 680
Book Description
Publisher:
ISBN:
Category : Aerodynamics
Languages : en
Pages : 680
Book Description
Development of an Aeroacoustic Methodology to Evaluate Heatshield Material Performance
Author: A. L. Laganelli
Publisher:
ISBN:
Category : Ablative materials
Languages : en
Pages : 144
Book Description
An experimental program was conducted in the AFWAL Mach 6 and AEDC shock Tube facilities in which acoustic fluctuating pressure data were acquired on flat plate TWCP specimens featuring smooth and rough surfaces. The TWCP specimens were instrumented with five Gulton microphones. The microphones placed in the model consisted of flush, ported, and backface (blind hole) locations. Several l/d ported orifices were examined as well as depths from the boundary layer surface for the backface gages. The AEDC tests were structured to examine optimum ported orifices prior to the AFWAL Mach 6 tests. The TWCP specimens were exposed to turbulent boundary layer conditions at tunnel stagnation pressures of 700, 1400, and 2100 psi with a total temperature of 1100 deg. R, respectively. A correlation was developed for the ported hole sensors that can be related to the flush mounted sensors. Characterizing the backface (blind hole) gages with surface mounted sensors will require further data interpretation due to vibration. In general, rough walls augmented the acoustic energy levels as expected. A biased rough pattern (20 deg, angled to flow) indicated that acoustic measurements could be used as a diagnostic technique to determine the surface characteristics of TWCP ablation patterns.
Publisher:
ISBN:
Category : Ablative materials
Languages : en
Pages : 144
Book Description
An experimental program was conducted in the AFWAL Mach 6 and AEDC shock Tube facilities in which acoustic fluctuating pressure data were acquired on flat plate TWCP specimens featuring smooth and rough surfaces. The TWCP specimens were instrumented with five Gulton microphones. The microphones placed in the model consisted of flush, ported, and backface (blind hole) locations. Several l/d ported orifices were examined as well as depths from the boundary layer surface for the backface gages. The AEDC tests were structured to examine optimum ported orifices prior to the AFWAL Mach 6 tests. The TWCP specimens were exposed to turbulent boundary layer conditions at tunnel stagnation pressures of 700, 1400, and 2100 psi with a total temperature of 1100 deg. R, respectively. A correlation was developed for the ported hole sensors that can be related to the flush mounted sensors. Characterizing the backface (blind hole) gages with surface mounted sensors will require further data interpretation due to vibration. In general, rough walls augmented the acoustic energy levels as expected. A biased rough pattern (20 deg, angled to flow) indicated that acoustic measurements could be used as a diagnostic technique to determine the surface characteristics of TWCP ablation patterns.
Fluctuating Pressure Loads Under High Speed Boundary Layers
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 18
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 18
Book Description
AIAA 12th Aeroacoustics Conference
Author:
Publisher:
ISBN:
Category : Airplane sounds
Languages : en
Pages : 568
Book Description
Publisher:
ISBN:
Category : Airplane sounds
Languages : en
Pages : 568
Book Description
DGLR/AIAA 14th Aeroacoustics Conference
Author: Hanno Heller
Publisher:
ISBN:
Category : Aerodynamic noise
Languages : en
Pages : 518
Book Description
Publisher:
ISBN:
Category : Aerodynamic noise
Languages : en
Pages : 518
Book Description