https://purehost.bath.ac.uk/ws/files/508962/Progress%2520in%2520Aerospace%2520Sciences%2520review%2520article%2520final%2520version.pdf

Unsteady aerodynamics of nonslender delta wings

Aeroelasticity is still dynamic, challenging, and a key part of cutting-edge airplane technology. Emerging trends, as well as challenges and needs in the field of airplane aeroelasticity, are surveyed and discussed. The paper complements other overview papers on various aspects of the fixed-wing aeroelastic problem, published recently for the centennial year of flight. It includes an extensive bibliography and emphasizes those aspects of aeroelastic technology development not covered thoroughly elsewhere.

Future of Airplane Aeroelasticity

Adaptive wing and flow control technology

A review of the Magnus effect in aeronautics

This paper focuses on the evaluation of the dynamic stability derivative formulation. The derivatives are calculated using the Euler and Reynolds-averaged Navier–Stokes equations, and a time-domain solver was used for the computation of aerodynamic loads for forced periodic motions. To validate the predictions, two test cases are used. For the standard dynamic model geometry, a database of dynamic simulations illustrates the effects of the systematic variation of motion and fluid parameters involved. A satisfactory agreement was observed with available experimental data, and the dependency of dynamic derivatives on a number of parameters, such as Mach number, mean angle of attack, frequency, and amplitude, was assessed. For the transonic cruiser wind-tunnel geometry, static and unsteady aerodynamic characteristics were validated against experimental measurements. The ability of models based on the dynamic derivatives to predict large-amplitude motion forces and moments was assessed. It was demonstrated that the dynamic derivative model does not represent all of the important effects due to aerodynamics.

Evaluation of Dynamic Derivatives Using Computational Fluid Dynamics

Analysis of recent test results obtained on strut-mounted aircraft models has revealed the presence of test facility interference effects. In addition to dynamic support interference, coupling with unsteady wall interference effects can be present even when the model is relatively small in relation to the test section size. This coupled support/wall interference is expected to be more prevalent in pitch-oscillation than in roll-oscillation tests. Significant interference of this type was identified in dynamic cross-coupling data obtained on the standard dynamics model (SDM) oscillating in pitch. On the other hand, small distortions of the antisymmetrical static rolling moment characteristics and of the longitudinal aerodynamic characteristics measured on a 65-deg delta wing are shown to be attributable to the effect of direct support interference on vortex breakdown. For the oscillating delta wing, the support interference produces asymmetries in the measured longitudinal aerodynamic characteristics, which decrease with increasing roll rate.

Ground facility interference on aircraft configurations with separated flow

To predict the full-scale aerodynamics of a combat aircraft performing high-alpha maneuvers requires the combined usage of experimental and theoretical tools. The preferred experimental tool is the rotary rig because it provides simulation of one important component of advanced maneuvers, i.e., the velocity vector roll. The present paper analyzes the results obtained in the recently completed investigation by AGARD FDP Working Group 16. Anomalous results are obtained when attempting to simulate high-Reynolds-number rotary characteristics in subscale tests using boundary-layer trips alone or in combination with forebody strakes

Wind-Tunnel Aerodynamics in Rotary Tests of Combat Aircraft Models

An analysis of existing oscillatory and rotary test data was undertaken to identify the origins of the observed wind-tunnel interference effects and interpret the aircraft aerodynamic characteristics. Logical arguments based on the limited experimental data point to the existence of interference flow mechanisms involving the coupling between unsteady flowfields near the model, the tunnel walls, and around the model support. Oscillatory crosscoupling derivatives measured on the standard dynamics model were significantly affected at low angles of attack while the nonlinear yawing moment characteristics of the HIRM 2 aircraft configuration at high incidence were masked completely in rotary tests performed in a small test section. Both of these very different problems may be attributed to unsteady wind-tunnel interference. Analytical corrections are not feasible at present, but experimental solutions can be implemented. Predictions of vehicle dynamics at high alpha based on dynamic wind-tunnel data can be affected by the interpretation given to the prevailing interference flow phenomena.

Unsteady wind-tunnel interference in aircraft dynamic experiments

A critical examination of recent dynamic test results obtained at high angles of attack reveals that various kinds of ground facility interference effects can distort the measurements. Particular problems are posed by both asymmetric and symmetric support structures. It is also found that the fuselage-like structures commonly used to attach a sting or strut to the model can cause unacceptable distortion of the high-alpha steady and unsteady aerodynamic characteristics.

Ground Facility Interference Effects on Slender Vehicle Unsteady Aerodynamics

Extensive efforts have been directed toward the development of the means by which the flow separation asymmetry occurring on an axisymmetric slender forebody at very high angles of attack could be controlled in order to improve the agility of advanced aircraft and missiles. To control the asymmetric flow separation represents a great challenge, and only a few of the investigated flow-control concepts have led to viable solutions. The fluid-mechanical processes associated with steady and alternating-pulsed blowing applications are analyzed in an effort to define flow mechanisms that can cause the observed anomalous control characteristics

Martin E. Beyers

Papers

Ground facility interference on aircraft configurations with separated flow

Wind-Tunnel Aerodynamics in Rotary Tests of Combat Aircraft Models

Unsteady wind-tunnel interference in aircraft dynamic experiments

Ground Facility Interference Effects on Slender Vehicle Unsteady Aerodynamics

Forebody Flow Control at Conditions of Naturally Occurring Separation Asymmetry