Numerical Prediction of Pitch Damping Stability Derivatives for Finned Projectiles

Bhagwandin, Vishal A.; Sahu, Jubaraj

doi:10.21236/ada592550

Cited by 8 publications

(14 citation statements)

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“…Several orders of magnitude reduction in the global residuals and at least one order of magnitude reduction in inner time step residuals were required. Grid convergence studies have also been performed in previous work [18,19] where similar meshes were used to predict aerodynamic forces and moments that were in excellent agreement with the experimental data. As a result, the computational grid used here is thus deemed sufficient to produce the desired accuracy of forces and moments for the same projectile geometry.…”

Section: Computational Trajectory Generationmentioning

confidence: 96%

“…For the inner iterations, the time step is allowed to vary spatially and is selected to help satisfy the physical transient equations to the desired degree. Often, several internal iterations (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) are required, depending on the magnitude of the outer time step, the nature of the problem and boundary conditions, and the consistency of the mesh with respect to the physics at hand. In the present work, an outer time step of 1.745 × 10 −4 s and 10 inner iterations were used for all virtual fly-out simulations.…”

Section: Computational Trajectory Generationmentioning

confidence: 99%

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Aerodynamic Characterization of a Microspoiler System for Supersonic Finned Projectiles

Scheuermann¹,

Costello²,

Silton³

et al. 2015

Journal of Spacecraft and Rockets

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Section: Computational Trajectory Generationmentioning

confidence: 96%

Section: Computational Trajectory Generationmentioning

confidence: 99%

Aerodynamic Characterization of a Microspoiler System for Supersonic Finned Projectiles

Scheuermann¹,

Costello²,

Silton³

et al. 2015

Journal of Spacecraft and Rockets

Self Cite

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“…For the forced planar pitching motion the pitching rate and the time rate of change of angle of attack are equal (Bhagwandin and Sahu, 2014) (equation ( 4)):…”

Section: Investigation Of the Flight Behaviormentioning

confidence: 99%

“…Equation ( 7) can be discretized and the PDMC can be calculated using the pitching moment coefficients which are taken from time-resolved numerical simulations. Common values for the pitching amplitude A are 0.25°and 0.1 for the reduced pitching frequency (Bhagwandin and Sahu, 2014). Equation ( 9) allows to calculate the pitching frequency and the oscillation time from the reduced pitching frequency: HFF 30,9…”

Section: Investigation Of the Flight Behaviormentioning

confidence: 99%

Investigation of the flight behavior of a flare-stabilized projectile using 6DoF simulations coupled with CFD

Klatt

Proff

Hruschka

2019

HFF

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Purpose The present work aims to investigate the capabilities of accurately predicting the six-degrees-of-freedom (6DoF) trajectory and the flight behavior of a flare-stabilized projectile using computational fluid dynamics (CFD) and rigid body dynamics (RBD) methods. Design/methodology/approach Two different approaches are compared for calculating the trajectory. First, the complete matrix of static and dynamic aerodynamic coefficients for the projectile is determined using static and dynamic CFD methods. This discrete database and the data extracted from free-flight experiments are used to simulate flight trajectories with an in-house developed 6DoF solver. Second, the trajectories are simulated solving the 6DoF motion equations directly coupled with time resolved CFD methods. Findings Virtual fly-out simulations using RBD/CFD coupled simulation methods well reproduce the motion behavior shown by the experimental free-flight data. However, using the discrete database of aerodynamic coefficients derived from CFD simulations shows a slightly different flight behavior. Originality/value A discrepancy between CFD 6DoF/RBD simulations and results obtained by the MATLAB 6DoF-solver based on discrete CFD data matrices is shown. It is assumed that not all dynamic effects on the aerodynamics of the projectile are captured by the determination of the force and moment coefficients with CFD simulations based on the classical aerodynamic coefficient decomposition.

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“…The dual time stepping mode of the CFD code has been used to conduct the transient URANS simulations. This procedure, which requires the adequate determination of an “outer” physical time-step together with an “inner” time-step, has been largely used in the past to investigate unsteady weapon aerodynamics (Sahu, 2006; Simon, 2007; Sahu, 2011; Bhagwandin and Sahu, 2014). The outer time-step Δ t is a global physical one representing the varying time discretization of the varying physical time term.…”

Section: Aerodynamic Quantificationmentioning

confidence: 99%

Aerodynamic prediction of a projectile fitted with fins

Decrocq

Martinez

Albisser

et al. 2018

HFF

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Purpose The present paper deals with weapon aerodynamics and aims to describe preliminary studies that were conducted for developing the next generation of long-range guided ammunition. Over history, ballistic research scientists were constantly investigating new artillery systems capable of overcoming limitations of range, accuracy and manoeuvrability. While futuristic technologies are increasingly under development, numerous issues concerning current powdered systems still need to be addressed. In this context, the present work deals with the design and the optimization of a new concept of long-range projectile with regard to multidisciplinary fields, including flight scenario, steering strategy, mechanical actuators or size of payload. Design/methodology/approach Investigations are conducted for configurations that combine existing full calibre 155 mm guided artillery shell with a set of lifting surfaces. As the capability of the ammunition highly depends on lifting surfaces in terms of number, shape or position, a parametric study has to be conducted for determining the best aerodynamic architecture. To speed-up this process, initial estimations are conducted thanks to low computational cost methods suitable for preliminary design requirements, in terms of time, accuracy and flexibility. The WASP code (Wing-Aerodynamic-eStimation-for-Projectiles) has been developed for rapidly predicting aerodynamic coefficients (static and dynamic) of a set of lifting surfaces fitted on a projectile fuselage, as a function of geometry and flight conditions, up to transonic velocities. Findings In the present study, WASP predictions at Mach 0.7 of both normal force and pitching moment coefficients are assessed for two configurations. Originality/value Analysis is conducted by gathering results from WASP, computational-fluid-dynamics (CFD) simulations, wind-tunnel experiments and free-flight tests. Obtained results demonstrate the ability of WASP code to be used for preliminary design steps.

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Numerical Prediction of Pitch Damping Stability Derivatives for Finned Projectiles

Cited by 8 publications

References 0 publications

Aerodynamic Characterization of a Microspoiler System for Supersonic Finned Projectiles

Aerodynamic Characterization of a Microspoiler System for Supersonic Finned Projectiles

Investigation of the flight behavior of a flare-stabilized projectile using 6DoF simulations coupled with CFD

Aerodynamic prediction of a projectile fitted with fins

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