• Journal of computational fluids engineering
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• v.8 no.3
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• pp.7-11
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• 2003

Accurate assessment of the effect of jet plume on the boattail pressure drag of transonic airbreathing missiles is very important to reduce drag and to satisfy the flight range and the required maneuver. Numerical results of drag analysis for boattail and base pressures due to jet plume are presented considering the turbulence modeling. Drag assessment due to the size of jet plume, the conditions of the exhaust gas, the configurations of the boattail, and transonic mach numbers is included.

• Journal of Aerospace System Engineering
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• v.17 no.6
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• pp.82-93
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• 2023

In this paper, nonlinear transonic flutter analyses of a composite missile fin considering the effect of delamination are conducted. An effective modal analysis methodology is adopted and verified with the experimental modal test data for laminated composite plates with delamination. Extended version of the in-house computational aeroelastic analysis program with the transonic small-disturbance (TSD) code is used in order to predict the flutter dynamic pressure of the delaminated composite fin models. In the subsonic, transonic, and supersonic flow regions, nonlinear time-domain flutter analyses are performed for various delamination conditions, and aeroelastic characteristics due to the delamination phenomena are examined in detail.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.914-920
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• 2002

Nonlinear flow-induced vibration characteristics of a generic missile wing (or control surface) are investigated in this study. The wing model has freeplay structural nonlinearity at its pitch axis. Nonlinear aerodynamic flows with unsteady shock waves are considered in the transonic flow region. To practically consider the effects of freeplay structural nonlinearity, the fictitious mass method (FMM) is applied to structural vibration analysis based on a finite element method (FEM). A computational fluid dynamics (CFD) technique is used for computing the nonlinear unsteady aerodynamics of all-movable wings. The aerodynamic analysis is based on the efficient transonic small-disturbance aerodynamic equations of motion using the potential-flow theory. To solve the nonlinear aeroelastic governing equations including the freeplay effect, a modal-based computational structural dynamic (CSD) analysis technique based on fictitious mass method (FMM) is used in time-domain. In addition, CSD and unsteady CFD techniques are simultaneously coupled to give accurate computational results. Various aeroelastic computations have been performed for a generic missile wing model. Linear and nonlinear aeroelastic computations have been conducted and the characteristics of flow-induced vibration are introduced.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2002.04a
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• pp.41-42
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• 2002

The powered missiles with very high thrust level can make highly underexpanded jet plume downstream of tile exhaust nozzle exit so that strong interactions between the exhaust plume and a free stream occur around the body at transonic or supersonic speeds. The interactions result in extremely complicated flow phenomena, which consist of plume-induced boundary layer separation, strong shear layers, various shock waves, and interactions among these. The flow characteristics are inherent nonlinear and severe unstable during the flight at its normal speed as well as taking-off and landing. Eventually, the induced boundary layer separation and pitching and yawing moments by the interactions cause undesirable effects ell the static stability and control of a missile.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.389.2-389
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• 2002

Nonlinear aeroelastic characteristics of a missile control surface are investigated in this study. The wing model has freeplay structural nonlinearity at its pitch axis. Nonlinear aerodynamic flows with unsteady shock waves are also considered in high-speed flow region. To effectively consider a freeplay structural nonlinearity, the fictitious mass method (FMM) is applied to structural vibration analysis based on finite element method (FEM). (omitted)

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.1
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• pp.45-54
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• 2022

There has been necessity to supplement the fin database to improve the accuracy of low-fidelity aerodynamic solver for missile configuration. In this study, fin database is expanded by in-house solver, utilized in the triservice data the previously established into regions beyond means of CFD. Fin alone data of CFD analysis results in the original region is matched well with triservice data originated from the wind tunnel tests. Extensive fin aerodynamic data from CFD analysis is added to the existing database of the low-fidelity solver. For confirmation, aerodynamic characteristics of body-tail and body-canard-tail missile configurations is computed using upgraded low-fidelity solver at transonic region. The result using improved solver shows good agreements with wind tunnel test and CFD analysis results, which implies that it becomes more accurate.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1730-1735
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• 2003

The plume-induced shock wave is a complex phenomenon, consisting of plume-induced boundary layer separation, separated shear layer, multiple shock waves, and their interactions. The knowledge base of plume interference effect on powered missiles and flight vehicles is not yet adequate to get an overall insight of the flow physics. Computational studies are performed to better understand the flow physics of the plume-induced shock and separation particularly at high plume to exit pressure ratio. Test model configurations are a simplified missile model and two rounded and porous afterbodies to simulate moderately and highly underexpanded exhaust plumes at the transonic/supersonic speeds. The result shows that the rounded afterbody and porous wall attached at the missile base can alleviate the plume-induced shock wave phenomenon, and improve the control of the missile body.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.2
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• pp.12-20
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• 2002

Three dimentional unsteady Euler equations are solved and an integration method is presented to predict the dynamic stability derivatives of transonic missiles. Results for the Basic Finner model are compared with several experimental data to vaildate the prediction capability of the present method. The variations of dynamic stability derivatives are discussed with respect to angle of attack, Mach number, and rotation rate. Results show that shock waves between fins enhance the pitch-damping characteristics in transonic region. Results also imply that the Euler equations can give the damping coefficients with comparable accuracy.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.8
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• pp.118-128
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• 2004

Exhaust plume effects on longitudinal aerodynamics of missile were investigated by wind tunnel tests using a solid plume simulator and CFD analyses with both the solid plume and air jet plumes. Approximate plume boundary prediction technique was used to produce the outer shape of the solid plumer and chamber conditions and nozzle shapes of the air jet plumes were determined through plume modeling technique to compensate the difference in thermodynamic properties between air and real plume. From comparisons among turbulence models in case of external flow interaction with the air jet plume, Spalart-Allmaras model turned out to give accurate result and to be less grid-dependent. Effects induced by the plume were evaluated through the computations with Spalart-Allmaras turbulence model and the air jet plume to account for various ratios of chamber and ambient pressure and Reynolds number under the flight test condition.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.10
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• pp.745-752
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• 2020

A numerical study was carried out to evaluate the aerodynamic characteristics of the supersonic grid fins installed on SpaceX Falcon 9. The unit-grid-fin concept was utilized for more efficient and simpler 3-D steady flow calculations. Pre- and post-correction processes that accounted the interference effects by the angle of attack of the missile, the influences of the outer frame of the grid fin and the connecting rods were improved in the study, and it was demonstrated that the present correction method was more accurate as compared to previous studies. Finally, the present approach was applied to evaluate the aerodynamic characteristics in transonic/supersonic flights of SpaceX Falcon 9 with various angle of attacks.