Aerodynamic Characteristics Of Aircraft Research Articles

Study of Power Influences to the Wing-Mounted Civil Aircraft Aerodynamic Characteristics

Numerical simulations of the power influences to the wing-mounted civil aircraft aerodynamic characteristics are presented. Three-dimensional time-dependent compressible Reynolds-averaged Navier–Stokes equations were solved. The point-to-point patched multiblock technology was used to generate the high-quality grid. For simulating the engine power effects, the jet inlet and jet exit boundary conditions were properly specified. The simulation results and their comparisons with the experimental data are presented for two test cases: an isolated engine and the DLR F6 wing–body/pylon/nacelle combination. The simulated and experimental results are quite similar, indicating the mesh quality and numerical methods are adequate in this study. Finally, flowfields around a realistic wing-mounted aircraft cruise and high-lift configuration were simulated. The numerical results indicate that the power changes the local flowfield, therefore causing certain changes to the aerodynamic characteristics.

Performance Evaluation of Two-Equation Turbulence Models for 3D Wing-Body Configuration

Numerical simulations of 3D aircraft configurations are performed in order to understand the effects of turbulence models on the prediction of aircraft's aerodynamic characteristics. An in-house CFD code that solves 3D RANS equations and two-equation turbulence model equations are used. The code applies Roe's approximated Riemann solver and an AF-ADI scheme. Van Leer's MUSCL extrapolation with van Albada's limiter is also adopted. Various versions of Menter's <TEX>$k-{\omega}$</TEX> SST turbulence models as well as Coakley's <TEX>$q-{\omega}$</TEX> model are incorporated into the CFD code. Menter's <TEX>$k-{\omega}$</TEX> SST models include the standard model, the 2003 model, the model incorporating the vorticity source term, and the model containing controlled decay. Turbulent flows over a wing are simulated in order to validate the turbulence models contained in the CFD code. The results from these simulations are then compared with computational results from the <TEX>$3^{rd}$</TEX> AIAA CFD Drag Prediction Workshop. Numerical simulations of the DLR-F6 wing-body and wing-body-nacelle-pylon configurations are conducted and compared with computational results of the <TEX>$2^{nd}$</TEX> AIAA CFD Drag Prediction Workshop. Aerodynamic characteristics as well as flow features are scrutinized with respect to the turbulence models. The results obtained from each simulation incorporating Menter's <TEX>$k-{\omega}$</TEX> SST turbulence model variations are compared with one another.

Experimental Investigation on the Characteristics of Sliding Discharge Plasma Aerodynamic Actuation

A new electrical discharge called sliding discharge was developed to generate plasma aerodynamic actuation for flow control. A microsecond-pulse high voltage with a DC component was used to energize a three-electrode actuator to generate sliding discharge. The characteristics of plasma aerodynamic actuation by sliding discharge were experimentally investigated. Discharge morphology shows that sliding discharge is formed when energized by properly adjusting microsecond-pulse and DC voltage. Compared to dielectric barrier discharge (DBD), the plasma extension of sliding discharge is quasi-diffusive and stable but longer and more intensive. Results from particle image velocimetry (PIV) test indicate that plasma aerodynamic actuation by sliding discharge can induce a ‘starting vortex’ and a quasi-steady ‘near-wall jet’. Body force induced by plasma aerodynamic actuation is about the order of mN, which is stronger than that induced by single DBD. It is inferred that microsecond-pulse sliding discharge may be more effective to generate large-scale plasma aerodynamic actuation, which is very promising for improving aircraft aerodynamic characteristics and propulsion efficiency.

Modeling Performance and Emissions from Aircraft in the Aviation Integrated Modelling Project

A new computational method has been developed that simulates the performance of a civil aircraft and determines the fuel consumption and emissions throughout the flight trajectory by linking the main aircraft aerodynamic characteristics with a model of engine performance. The performance emission simulation of aircraft operations model responds to the needs of the Aviation Integrated Modelling project by delivering a computationally fast and reliable model able to simulate aircraft performance, fuel use, and emissions. The methodology implies that the airframe aerodynamic characteristics and the performance of the engine are modeled by generic nondimensional relationships and related through the equations of motion. These nondimensional characteristics are sufficient to enable accurate determination of the forces acting on the aircraft, the fuel burn of the engine, and the key parameters that determine the emissions of pollutants such as nitrous oxides. Within this paper, this nondimensional approach is demonstrated and validated using comparisons with flight data from commercial aircraft operations. The results show that the model can accurately simulate civil aircraft performance for a range of f light conditions and operating procedures. In future work with the Aviation Integrated Modelling project, the method will be further developed and applied to investigate novel aircraft technologies, new operating procedures, and the use of alternative fuels.

Aerodynamic characteristics of propeller in non‐axial flow

AbstractFlow on running propellers installed on aircraft in general case is not axial what results in off‐axis forces and moments at the propeller. Lifting line method is applied for propeller blade model using set of discrete vortex filaments. Propeller wake defined by vortex sheet of discrete vortex filaments is modelled with application of free‐wake method. Presented propeller model combines the blade and the wake model and with its low computational cost realization it is suitable for preliminary prediction of propeller contribution to the aircraft aerodynamic characteristics. (© 2008 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Experimental Investigation of Vectoring Jet on Aerodynamic Characteristics of Aircraft

Thrust vectoring is one of the advanced technologies in the design of the fourth generation fighter to provide high maneuverability andagility. Thepurposeof thispaper istoinvestigate theeffectof thevectoring jet onaerodynamic characteristics of a modern fighter. The tests are conducted in a transonic wind tunnel with a square test section of 0:6 � 0: 6m and a low speed wind tunnel with a 0:8 � 1m elliptical test section. The test results are obtained at a Mach number of 0.4 or 0.8 and a Reynolds number of 9:5 � 10 6 or 15:6 � 10 6 per meter at angles of attack ranging from0to23degforahighspeedtest,andat45 m=sforalowspeedtestandReynoldsnumberof3 � 10 6 permeterat angles of attack ranging from 0 to 45 deg. High-pressure air is used to simulate the jet flow, and the nozzle pressure ratioisvariedfrom1.0(jetoff)to4.Onemodern fightermodelisemployedanddividedintotwopartsofforebodyand afterbody for force-measuring, respectively. As a result, the interaction behaviors are obtained.

Design of a Three Surfaces R/C Aircraft Model

Design of a three lifting surfaces radio-controlled model has been carried out at Dipartimento di Progettazione Aeronautica (DPA) by the authors in the last year. The model is intended to be a UAV prototype and is now under construction. The main goal of this small aircraft's design is to check the influence of the canard surface on the aircraft's aerodynamic characteristics and flight behavior, especially at high angles of attack. The aircraft model is also intended to be a flying platform to test sensors, measurement and acquisition systems for research purposes and a valid and low-cost teaching instrument for flight dynamics and flight maneuvering. The aircraft has been designed to fly with and without canard, and all problems relative to aircraft balance and stability have been carefully analyzed and solved. The innovative configuration and the mixed wooden-composite material structure has been obtained with very simple shapes and all the design is focused on realizing a low-cost model. A complete aerodynamic analysis of the configuration up to high angles of attack and a preliminary aircraft stability and performance prediction will be presented.

Determination of the aerodynamic characteristics of aircraft in the transonic velocity range

The problem of determining the integral aerodynamic characteristics of aircraft as a whole in the transonic velocity range is considered. An approximate method of their calculation is developed using the nonlinear transonic theory of small perturbations for three-dimensional flow over a body. The method of investigation consists in separating the flow region into two subregions (outer and inner), applying numerical methods of integrating the equations in those regions, and joining the solutions. The Murman-Cole method of calculating the pressure drag of an isolated wing is generalized to the case of a combination of wing and fuselage.

Unsteady wind-tunnel interference in aircraft dynamic experiments

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.

Computer calculation of aerodynamic characteristics of aircraft at supersonic velocities

A previous study by one of the present authors [1] listed a number of works dedicated to calculation of aerodynamic characteristics of aircraft of complex physical construction at supersonic velocities. A method for calculating the flow around a system of small-scale bearing surfaces was developed. The method reduces to determination of the velocity potential Φ with subsequent differentiation to determine pressure. The present study will present a method of calculating stationary aerodynamic characteristics of aircraft of extensive size at supersonic velocities, in which the basic unknown function is the perturbed pressure p′. Eliminating numerical differentiation from the calculation permits an increase in accuracy of the results obtained. The problem is solved for an entire airplane with consideration of the craft's thickness.

Jet Transports Characteristics Related to Airports

The changes in design and performance of jet transports, since they were first introduced in commercial service, are reviewed, particularly as these changes affect airports. The trend is to manufacture aircraft with higher thrust-to-weight ratios than their predecessors. This factor, along with improvements in the aerodynamic characteristics of aircraft, has been beneficial in preventing an increase in runway length and reducing noise over populated areas. There is a trend toward mounting engines on the fuselage aft of the wings, rather than suspending them from the wings. All new subsonic aircraft will be equipped with turbo-fan engines. These engines are less noisy on the exhaust end than turbojet engines, and are therefore better for takeoff. However, for landing, the compressor whine of the fan engine is more irritating. For aircraft with long wheel bases, radii of curvature of new taxiways should not be less than 300 to 400 ft. Existing taxiways with smaller radii will require widening.

Recent Research on the Improvement of the Aerodynamic Characteristics of Aircraft

The object of the present paper is to draw attention to some of the recent researches which have had as object the improvement of the aerodynamic characteristics of aircraft. Such characteristics can be classified into two groups; those concerned with performance and those concerned with stability and control. In the former group come all those researches which aim at the reduction of drag, while in the latter group come those directed to the attainment of satisfactory stability and control in normal flight, as well as those concerned with the behaviour of auxiliary devices such as flaps and slots which are used under special conditions and in particular during landing and taking-off. The problems associated with flutter also belong to this group. The two groups may be broadly characterised by the words economy and safety.