Aeroprediction Inc.

King George, VA, United States

Aeroprediction Inc.

King George, VA, United States
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Moore F.G.,Aeroprediction Inc. | Moore L.Y.,Aeroprediction Inc. | McGowan G.,Corvid Technologies, Inc.
AIAA Atmospheric Flight Mechanics Conference, 2015 | Year: 2015

An Improved Method to Calculate the Nonlinear Rolling Moment Due to Differential Fin Deflection of Canard Controlled Missiles has been developed. The method utilized a Computational Fluid Dynamics Data Base using the wing controlled Seasparrow as a baseline configuration. Improvements to the nonlinear rolling moment incorporated as a result of the new database include: a) accounting for fin interference as a function of angle of attack and Mach number, b) approximating the change in the leeward plane tail fin lateral center of pressure as a function of angle of attack and Mach number, and c) estimating the nonlinear change in rolling moment on the leeward plane tail fin as a function of angle of attack and Mach number. These improvements were incorporated into the 2013 version of the Aeroprediction Code to be released in 2014. Comparison of the improved method to existing approximate techniques and experimental data was made on several configurations. The improved method did a much better job in predicting the nonlinearities in roll moment due to differential fin deflection on all the configurations investigated than existing semiempirical codes, including the 2013 release of the Aeroprediction Code. © 2015 by Aeroprediction, Inc.


Eidell M.R.,Corvid Technologies, Inc. | Nance R.P.,Corvid Technologies, Inc. | McGowan G.Z.,Corvid Technologies, Inc. | Carpenter V J.G.,Corvid Technologies, Inc. | Moore F.G.,Aeroprediction Inc.
30th AIAA Applied Aerodynamics Conference 2012 | Year: 2012

Results from computational fluid dynamics (CFD) predictions of roll damping on three elementary missile configurations are presented in this work. RavenCFD, a three-dimensional unstructured-grid Navier-Stokes solver, is used in conjunction with a rigid body motion (RBM) capability and an embedded six-degree-of-freedom (6-DOF) solver to simulate both prescribed rolls and free-to-roll configurations. Several different methodologies are applied to both prescribed-roll and free-to-roll CFD calculations to obtain estimates of roll damping coefficient across a broad range of Mach numbers. In general, the computational results agree well with experimental roll-damping measurements across the range of Mach numbers and angles of attack considered. © 2012 by Corvid Technologies.


Mcgowan G.Z.,Corvid Technologies, Inc. | Kurzen M.J.,Corvid Technologies, Inc. | Nance R.P.,Corvid Technologies, Inc. | Carpenter V J.G.,Corvid Technologies, Inc. | Moore F.G.,Aeroprediction Inc.
30th AIAA Applied Aerodynamics Conference 2012 | Year: 2012

The capability of accurately estimating pitch damping values for missile-like geometries over a range of Mach numbers and at high angles of attack using state-of-the-art CFD techniques has been investigated. Toward this effort three geometries were examined: the Army-Navy Finner model, the extended Army-Navy Finner model, and the M823 research store. Pitch damping values are predicted using forced oscillation calculations performed with the RavenCFD Navier-Stokes flow solver. Additionally, pitch decay calculations and aerodynamic build-up methods are also employed using the RavenCFD solver. These methods are compared to both experimental results and AP09, a fast-running engineering tool. Pitch damping variations due to geometric changes, Mach number changes, and angle of attack changes are explored with each method. Overall, each CFD method exhibits an outstanding agreement with experiment and range data at the lower angles of attack. Both pitch decay and forced oscillation approaches provide good agreement for low-to-moderate angles. At angles of attack greater than 30 degrees, the forced oscillation approach provides the best agreement. Pitch damping variations at angles higher than 60-70 degrees for the Army-Navy Finner have been shown to be a peripheral effect of the extreme unsteadiness of the wake flow at these conditions. © 2012 by Corvid Technologies.


McGowan G.Z.,Corvid Technologies, Inc. | Kurzen M.J.,Corvid Technologies, Inc. | Nance R.P.,Corvid Technologies, Inc. | Carpenter V J.G.,Corvid Technologies, Inc. | Moore F.G.,Aeroprediction Inc.
Journal of Spacecraft and Rockets | Year: 2014

The capability of accurately estimating pitch-damping values for missilelike geometries over a range of Mach numbers and at high angles of attack using state-of-the-art computational-fluid-dynamics techniques has been investigated. Toward this effort, three geometries were examined: theArmy-Navy Finner model, the extendedArmy-Navy Finner model, and the M823 research store. Pitch-damping values are predicted using forced-oscillation calculations performed with the RavenCFD Navier-Stokes flow solver. Additionally, pitch-decay calculations and aerodynamic build-up methods are also employed using the RavenCFD solver. These methods are compared to both experimental results and AP09, a fast-running engineering tool. Pitch-damping variations due to geometric changes, Mach number changes, and angle-of-attack changes are explored with each method. Overall, each computationalfluid-dynamics method exhibits an outstanding agreement with experiment and range data at the lower angles of attack. Both pitch-decay and forced-oscillation approaches provide good agreement for low-to-moderate angles. At angles of attack greater than 30 deg, the forced-oscillation approach provides the best agreement. Pitch-damping variations at angles higher than 60-70 deg for the Army-Navy Finner have been shown to be a peripheral effect of the extreme unsteadiness of the wake flow at these conditions. Copyright © 2013 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.


Nelson A.C.,Corvid Technologies, Inc. | McGowan G.Z.,Corvid Technologies, Inc. | Moore F.G.,Aeroprediction Inc
53rd AIAA Aerospace Sciences Meeting | Year: 2015

Future missile designs must expand the current flight envelope to continue to be effective against next generation aircraft. As such, design tools must be improved to increase the accuracy of aerodynamic predictions over a larger range of flight conditions. Computational fluid dynamics (CFD) results of the Sparrow missile configuration over a wide range of flight attitudes and Mach numbers are presented herein to assist in the development of design tools, such as fast running semi-empirical engineering codes. In addition, the CFD results are used to investigate complex physical phenomena, such as wing-wing, wing-body, and wing-tailfin interaction to assist in developing modeling procedures. It was found that these interactions play a significant role in the nonlinearity of rolling moment at higher angles of attack. © 2015 by Corvid Technologies.


Moore F.G.,Aeroprediction Inc. | Moore L.Y.,Aeroprediction Inc.
Journal of Spacecraft and Rockets | Year: 2010

New technology has been developed and added to the power-on base drag prediction model in the aeroprediction code. The new technology showed improvement over the January 2009 release of the code compared with experiment for all cases considered. Of particular note is the capability to predict base pressure for power-off conditions and at all values of power-on including base bleed and values of thrust coefficient below where the minimum value of power-on base pressure occurs. To the authors' knowledge, this is the first theoretical method available to predict power-on base pressure at any value of thrust coefficient. Copyright © 2009 by Aeroprediction, Inc.


Moore F.G.,Aeroprediction Inc. | Moore L.Y.,Aeroprediction Inc.
50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition | Year: 2012

A new nonlinear method has been developed to predict the roll moments due to differential deflection of fins (often referred to as roll driving moment). The method utilizes the nonlinear aerodynamics currently available in the 2009 version of the Aeroprediction Code (AP09) for the horizontal wing alone and wing-body aerodynamics. Specialized treatment is given to the leeward and windward plane fins as well as engineering approximations to handle the physics associated with fin-to-fin interference, wing-tail interference, a fin in close proximity to a large wing upstream, and fins located on a boattail. Comparison of the new method to seven body tail configurations, five wing-body-tail cases with tail control and six wing-body-tail cases with canard control showed the new method followed the general trends of the experimental data for most cases. Results were quite good for most cases with the poorest agreement with experiment being for canard control cases where the tail fins were very large. Results from several of the cases where comparisons of the new theory to experiment have been made are presented in this paper. Copyright © 2012 by the American Institute of Aeronautics and Astronautics, Inc.


Moore F.G.,Aeroprediction Inc. | Moore L.Y.,Aeroprediction Inc.
Journal of Spacecraft and Rockets | Year: 2012

A new nonlinear method has been developed to predict the roll moments due to differential deflection of fins (often referred to as the roll driving moment). The method uses the nonlinear aerodynamics currently available in the 2009 version of the aeroprediction code (AP09) for the horizontal wing alone and wing-body aerodynamics. Specialized treatment is given to the leeward and windward plane fins as well as engineering approximations to handle the physics associated with fin-To-fin interference, wing-Tail interference, a fin in close proximity to a large wing upstream, and fins located on a boat tail. Comparison of the new method to seven body-Tail configurations, five wing- body-Tail cases with tail control, and six wing-body-Tail cases with canard control showed the new method followed the general trends of the experimental data for most all cases. Results were quite good for most cases, with the poorest agreement with experiment being for canard control cases where the canard and tail fins were very large. Users of the new methodology should therefore be cautious in using the method for canard control cases where both the canards and tail surfaces are large. Results from several of the cases where comparisons of the new theory to the experiment have been made are presented in this paper. Copyright © 2011 by Serhat Hosder.

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