Modeling the Rolling Moment on the 65-degree Delta Wing for Rolling Motions at High Angle of Attack PDF Download
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Author: James Harold Myatt
Publisher:
ISBN:
Category :
Languages : en
Pages : 342
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Author: James Harold Myatt
Publisher:
ISBN:
Category :
Languages : en
Pages : 342
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Author: Raymond E. Gordnier
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 50
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Book Description
This report presents computations of the flowfield around an 80 degree sweep delta wing undergoing a constant roll-rate maneuver from 0 to 45 degrees. The governing equations for the problem are the unsteady, three- dimensional Navier-Stokes equations. The equations are solved using the implicit, approximately-factored algorithm of Beam-Warming. Fixed roll angle results are also presented and compared with experimental measurements to demonstrate the ability of the numerical technique to accurately capture the flowfield around a rolled delta wing. The dynamic behaviors of the vortex position and strength, as well as their corresponding effect on surface pressure, lift and roll moment, are described. A simple, quasi-static explanation of these vortex behaviors based on effective angle-of-attack and sideslip angle is proposed ... Delta wing roll, Vortex dynamics, Vortical flow, Unsteady maneuver.
Author: Elizabeth M. Lee-Rausch
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 36
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Author: Lewis R. Fisher
Publisher:
ISBN:
Category : Vibration
Languages : en
Pages : 54
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 13
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Book Description
Since the need for improvements in high angle-of-attack maneuverability of aircraft's in transonic flight was of concern, a model was rotated around its longitudinal body axis with a dimensionless rolling rate of pi = 0.0762 (10 Hz), resulting in flow conditions with extensive vortical behavior and strongly non-linear, wing/vortex interference effects. This paper deals with validation experiments performed at the DLR Goettingen. The objective of this activity was to provide experimental data for comparison with numerical calculations performed within the international WEAG TA 15 group: Alenia (Italy), DERA (United Kingdom), DLR and EADS (Germany), and NLR (The Netherlands). A special 65 delta wing, the DLR PSP-model, was designed, manufactured and finally tested in the transonic 1mx 1m wind tunnel DNW-TWG in Goettingen. A rolling apparatus was built up to enable roll rates up to 10 Hz. A new sting concept was developed as elastic simulations showed dangerous problems associated with the rolling model exposed to the periodic aerodynamic load. The experiments were carried out at angles of attack alpha=10 and 17, M=0.8, Reynolds number of 5.3 Mio in the case of steady and 2.2 Mio for unsteady conditions. The model was equipped with only a few pressure taps for PSI and Kulite sensors, as surface pressure distributions of the model should be obtained using the pressure sensitive paint (PSP) technique, to measure the pressure all over the whole surface of the model. As the model was rotating an unsteady PSP technique had to be applied. Several steps had to be considered in order to finally use the measured pressure distributions for comparison with numerical predictions. In the case of steady conditions the results compare quite well with the conventional pressure taps and numerical calculations, in the case of the spinning model discrepancies between Kulite values and PSP as well as numerical results could be stated.
Author: Gregory A. Addington
Publisher:
ISBN:
Category : Aerodynamic load
Languages : en
Pages : 38
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Book Description
Recent analysis has shown that nearly every high-performance tactical aircraft in the inventory of American and allied air forces has experienced some sort of unexpected controlled-flight departure in the early stages of flight testing. Most, if not all, of these in-flight departures had characteristics which lead to the conclusion that they were the result of critical state encounters. Critical states are discrete flight mechanical state vector values where the aerodynamic response loses its analytic dependence on one or more of the variables in that state vector. Critical states manifest themselves as discontinuities in either magnitude or slope in static force and moment data, and as dynamic responses which may be nonlinear with respect to either geometric parameters and/or time. This report presents two analysis procedures which have shown promise in the detection of critical states. First, spectral analysis of data ensembles acquired during wind tunnel tests of two 65 degree delta wings has shown that changes in these spectra signal the presence of some critical states. Further, the nature of these spectra have in some instances provided insight into the nature of the dynamic response. The second analysis procedure involves comparing the static experimental data to a simple potential-flow-based numerical model. It was found that when the experimental dataset diverged from the numerical simulation, critical states were present. Both of these analysis procedures required no additional data to be acquired and minimal analytical effort. Therefore, they provide a cost-effective means for adverting the effects of critical states during early air vehicle test-and-evaluation programs.
Author: E. Claude Sanders
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 26
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Author: Thomas G. Gainer
Publisher:
ISBN:
Category : Aerodynamic measurements
Languages : en
Pages : 82
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Author: Lewis R. Fisher
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 54
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Author: Alex Goodman
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 82
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Book Description
An investigation was made to determine the effects of wing position and fuselage size on the low-speed static and rolling stability characterististics of airplane models having a triangular wing and vertical tail surfaces.
