Author: Robert L. Goldman
Publisher:
ISBN:
Category :
Languages : en
Pages : 81
Book Description
An experimental wind tunnel investigation has been performed to determine the important aerodynamic and structural parameters contributing to transonic control surface instabilities and related unsteady transonic flow phenomena on the lower flap and bottom surface of a lifting body configuration. The tests were conducted on a modified 0.2 scale model of the Air Force's SV-5 in the AEDC 16-foot Transonic Propulsion Wind Tunnel Facility. The model, its flap elastically restrained in rotation by an interchangeable flexure spring, was tested at Mach numbers ranging from 0.80 to 1.40 and at Reynolds numbers from 4,000,000 to 14,000,000 based on model length. Measurements of steady and unsteady pressures and flap hinge moments and high speed schlieren motion pictures were used to assess the character of the test observations for four different flap natural frequencies, at vehicle angles of attack between 10 deg and 30 deg and over a range of flap deflections from 0 deg to 45 deg. The results indicated the existence of a self-excited control surface instability. The response was related to the formation of shock waves in the vicinity of the flap and appeared to fit the classical descriptions of transonic buzz. When an instability did not occur the flap oscillations became random and non-divergent. The sensitivity of this type of response to pressure disturbances in the boundary layer seems to place these excitations in the buffet category. (Author).
Investigation of Transonic Control Surface Instabilities of a Lifting Body Configuration
Author: Robert L. Goldman
Publisher:
ISBN:
Category :
Languages : en
Pages : 81
Book Description
An experimental wind tunnel investigation has been performed to determine the important aerodynamic and structural parameters contributing to transonic control surface instabilities and related unsteady transonic flow phenomena on the lower flap and bottom surface of a lifting body configuration. The tests were conducted on a modified 0.2 scale model of the Air Force's SV-5 in the AEDC 16-foot Transonic Propulsion Wind Tunnel Facility. The model, its flap elastically restrained in rotation by an interchangeable flexure spring, was tested at Mach numbers ranging from 0.80 to 1.40 and at Reynolds numbers from 4,000,000 to 14,000,000 based on model length. Measurements of steady and unsteady pressures and flap hinge moments and high speed schlieren motion pictures were used to assess the character of the test observations for four different flap natural frequencies, at vehicle angles of attack between 10 deg and 30 deg and over a range of flap deflections from 0 deg to 45 deg. The results indicated the existence of a self-excited control surface instability. The response was related to the formation of shock waves in the vicinity of the flap and appeared to fit the classical descriptions of transonic buzz. When an instability did not occur the flap oscillations became random and non-divergent. The sensitivity of this type of response to pressure disturbances in the boundary layer seems to place these excitations in the buffet category. (Author).
Publisher:
ISBN:
Category :
Languages : en
Pages : 81
Book Description
An experimental wind tunnel investigation has been performed to determine the important aerodynamic and structural parameters contributing to transonic control surface instabilities and related unsteady transonic flow phenomena on the lower flap and bottom surface of a lifting body configuration. The tests were conducted on a modified 0.2 scale model of the Air Force's SV-5 in the AEDC 16-foot Transonic Propulsion Wind Tunnel Facility. The model, its flap elastically restrained in rotation by an interchangeable flexure spring, was tested at Mach numbers ranging from 0.80 to 1.40 and at Reynolds numbers from 4,000,000 to 14,000,000 based on model length. Measurements of steady and unsteady pressures and flap hinge moments and high speed schlieren motion pictures were used to assess the character of the test observations for four different flap natural frequencies, at vehicle angles of attack between 10 deg and 30 deg and over a range of flap deflections from 0 deg to 45 deg. The results indicated the existence of a self-excited control surface instability. The response was related to the formation of shock waves in the vicinity of the flap and appeared to fit the classical descriptions of transonic buzz. When an instability did not occur the flap oscillations became random and non-divergent. The sensitivity of this type of response to pressure disturbances in the boundary layer seems to place these excitations in the buffet category. (Author).
Investigation of Control-surface Instabilities on Lifting-body Reentry Vehicles at a Mach Number of 15.4
Author: Robert Charles Goetz
Publisher:
ISBN:
Category : Aerodynamics, Hypersonic
Languages : en
Pages : 60
Book Description
Publisher:
ISBN:
Category : Aerodynamics, Hypersonic
Languages : en
Pages : 60
Book Description
Investigation of Control Surface Instabilities of Lifting Body Configurations
Author: Robert L. Goldman
Publisher:
ISBN:
Category :
Languages : en
Pages : 128
Book Description
Based on aircraft experience, the possibility of the occurrence of unanticipated aeroelastic instabilities of advanced orbital and superorbital lifting body configurations is an appropriate consideration for the vehicle designer. Although oscillatory motions may involve any one of a number of aeroelastic mechanisms, most of them can be categorized as either self-sustained, driven by flow disturbances, or a combination of both forms. In the present investigation, such mechanisms are studied both analytically and experimentally. The investigation is actually the outgrowth of recent hypersonic wind tunnel tests in which control surface oscillations were observed on a re-entry vehicle model. It has been found that the oscillations that do occur are not self-sustained but instead involve a complex interaction between flow separation, free stream disturbances and vehicle geometry. In general, the response can be characterized as a low level, random, nondivergent oscillation with peak hinge moments that may be of the same order of magnitude as the static hinge moments. (Author).
Publisher:
ISBN:
Category :
Languages : en
Pages : 128
Book Description
Based on aircraft experience, the possibility of the occurrence of unanticipated aeroelastic instabilities of advanced orbital and superorbital lifting body configurations is an appropriate consideration for the vehicle designer. Although oscillatory motions may involve any one of a number of aeroelastic mechanisms, most of them can be categorized as either self-sustained, driven by flow disturbances, or a combination of both forms. In the present investigation, such mechanisms are studied both analytically and experimentally. The investigation is actually the outgrowth of recent hypersonic wind tunnel tests in which control surface oscillations were observed on a re-entry vehicle model. It has been found that the oscillations that do occur are not self-sustained but instead involve a complex interaction between flow separation, free stream disturbances and vehicle geometry. In general, the response can be characterized as a low level, random, nondivergent oscillation with peak hinge moments that may be of the same order of magnitude as the static hinge moments. (Author).
Investigation of Control-surface Instabilities on Lifting-body Reentry Vehicles at a Mach Number of 15.4
Author: Robert C. Goetz
Publisher:
ISBN:
Category :
Languages : en
Pages : 54
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 54
Book Description
NASA Technical Note
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 960
Book Description
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 960
Book Description
Technical Abstract Bulletin
Author:
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 850
Book Description
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 850
Book Description
Subsonic Aerodynamic Characteristics of the HL-20 Lifting-body Configuration
Author: George M. Ware
Publisher:
ISBN:
Category : Aerodynamics
Languages : en
Pages : 36
Book Description
Publisher:
ISBN:
Category : Aerodynamics
Languages : en
Pages : 36
Book Description
U.S. Government Research & Development Reports
Author:
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 1014
Book Description
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 1014
Book Description
Hypersonic and Transonic Buzz Measurements on the Lower Pitch Flap of M2-F2 Lifting Entry Configuration
Author: Robert William Warner
Publisher:
ISBN:
Category : Aerodynamics, Hypersonic
Languages : en
Pages : 52
Book Description
Free-oscillation damping measurements at hypersonic and transonic Mach numbers are presented for the lower pitch flap of the M2-F2 reentry vehicle. For the flow and model conditions tested, the damping measurements indicate the absence of hypersonic buzz instability for flap rotation frequencies of 47.3 Hz, 153 Hz, and 360 Hz, the presence of transonic buzz for 47.3 Hz flap, and the absence of transonic buzz for a 115 Hz flap. There are not enough flap damping data for an error estimate based on repeatability, but a partial damping calibration is presented in which an analog computer simulation of random flap response for a known flap damping is fed into the autocorrelation computer and filter combination used for most of the damping measurements.
Publisher:
ISBN:
Category : Aerodynamics, Hypersonic
Languages : en
Pages : 52
Book Description
Free-oscillation damping measurements at hypersonic and transonic Mach numbers are presented for the lower pitch flap of the M2-F2 reentry vehicle. For the flow and model conditions tested, the damping measurements indicate the absence of hypersonic buzz instability for flap rotation frequencies of 47.3 Hz, 153 Hz, and 360 Hz, the presence of transonic buzz for 47.3 Hz flap, and the absence of transonic buzz for a 115 Hz flap. There are not enough flap damping data for an error estimate based on repeatability, but a partial damping calibration is presented in which an analog computer simulation of random flap response for a known flap damping is fed into the autocorrelation computer and filter combination used for most of the damping measurements.
Scientific and Technical Aerospace Reports
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 312
Book Description
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 312
Book Description