VISCOUS CFD ANALYSIS OF GENERIC MISSILE WITH GRID FINSVISCOUS CFD ANALYSIS OF GENERIC MISSILE WITH GRID FINSBy Swapnil. D. Adhav.By Swapnil. D. Adhav.

Prof: D. R. KirkProf: D. R. KirkDepartment of Mechanical and Aerospace EngineeringDepartment of Mechanical and Aerospace Engineering

Florida Institute of Technology, Melbourne, FL 32901 Florida Institute of Technology, Melbourne, FL 32901

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OutlineOutline

BackgroundBackground

Model ConfigurationModel Configuration

Numerical TestsNumerical Tests

ResultsResults

Comparison of Grid fin with Planar finComparison of Grid fin with Planar fin

ConclusionConclusion

BackgroundBackground

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Comparison With the Planar FinsComparison With the Planar Fins

ObjectiveObjectiveObtain Aerodynamic coefficients and Obtain Aerodynamic coefficients and Viscous ForcesViscous Forces

Establish a data for comparison with Establish a data for comparison with the DERA wind tunnel data and ARL the DERA wind tunnel data and ARL studies for fluent work.studies for fluent work.

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Model ConfigurationModel ConfigurationTotal area of Air flow through the fin98 mm²

19 Grid per cell

Thickness of fin is 2mm

Numerical ModelingNumerical Modeling CFD ModelingCFD Modeling

a) 3D,Steay state.a) 3D,Steay state.

b) Implicit, b) Implicit,

c) coupled incompressiblec) coupled incompressible

d) Unstructured Mesh gridd) Unstructured Mesh grid

e) Mach Number 0.3e) Mach Number 0.3

Angle of Attack constantAngle of Attack constant

Boundary ConditionsBoundary ConditionsOutflow conditions at downstream, Velocity inlet in min z direction.Outflow conditions at downstream, Velocity inlet in min z direction.

Far field Boundary conditions for all surfaces.Far field Boundary conditions for all surfaces.

Re=1.2×10^6 (Turbulent Flow)Re=1.2×10^6 (Turbulent Flow)

Temperature=300k and Pressure=8325Pa,Pr=0.87Temperature=300k and Pressure=8325Pa,Pr=0.87

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Velocity contours at M=0.3Velocity contours at M=0.3

Results and DiscussionResults and Discussion Planar FinsPlanar Fins Grid FinsGrid Fins

C xC x C x C x viscousviscous

%% C xC x C xC x

ViscousViscous%%

DERADERA 0.0210.021 0.0040.004 2020 0.0720.072 0.0110.011 1515

ARLARL 0.0290.029 0.0090.009 2020 0.0870.087 0.0190.019 2121

DATADATA -- -- -- 0.0930.093 0.02150.0215 2222

A shock is formed in front of the grid fin. A shock is formed in front of the grid fin. The simulation compares well to experimentThe simulation compares well to experiment

Mach number 2.0 at Angle of attack=0˚

Mach Number 2.5

ConclusionConclusion

The simulations were also successful in calculating the flow The simulations were also successful in calculating the flow structure around the fin in the separated flow region. structure around the fin in the separated flow region.

The Physical nature of this effect was illustrated by presenting The Physical nature of this effect was illustrated by presenting contours of Velocity and pressure at Mach numbers 0.3.contours of Velocity and pressure at Mach numbers 0.3.

The viscous components of the axial force on the grid fin were The viscous components of the axial force on the grid fin were about 2 times greater than that on the planer fins. about 2 times greater than that on the planer fins.

Despite of some drawbacks, the improved maneuverability grid Despite of some drawbacks, the improved maneuverability grid fins offer at high supersonic speeds and high angles of attack fins offer at high supersonic speeds and high angles of attack have resulted in several grid fin research efforts in recent years.have resulted in several grid fin research efforts in recent years.

More recent efforts have focused on using computational fluid More recent efforts have focused on using computational fluid dynamics (CFD) to better understand the characteristics of the dynamics (CFD) to better understand the characteristics of the flow passing through the fins in order to better optimize their flow passing through the fins in order to better optimize their performance. performance.

ReferencesReferences““Computational Fluid Dynamics Analysis of Generic Missile with Grid fins by James Computational Fluid Dynamics Analysis of Generic Missile with Grid fins by James Desprito, Harris L Edge, Paul Weinacht, Jabaraj Sahu and surya dinavahi ARL-TR-2318 Desprito, Harris L Edge, Paul Weinacht, Jabaraj Sahu and surya dinavahi ARL-TR-2318 September 2000. Army research Lab.September 2000. Army research Lab.

““First Viscous CFD Analysis of Grid Fins gives better Prediction of Missile Trajectory” in First Viscous CFD Analysis of Grid Fins gives better Prediction of Missile Trajectory” in Journal Articles by Fluent Software users.Journal Articles by Fluent Software users.

Cartesian Grid Simulations of a canard controlled Missile with Spinning tail by Scott .M. Cartesian Grid Simulations of a canard controlled Missile with Spinning tail by Scott .M. Murman Eloret and Michael J Aftosmis NASA Ames Research Center CA, AIAA-2003-3670.Murman Eloret and Michael J Aftosmis NASA Ames Research Center CA, AIAA-2003-3670.

The research Analysis of aerodynamic numerical simulation of grid fins by WU pin, MA The research Analysis of aerodynamic numerical simulation of grid fins by WU pin, MA Yong-gang, CHEN chun Department of Computer science, chinaYong-gang, CHEN chun Department of Computer science, china..

WEBSITESWEBSITES1 .www.aerospaceweb.org1 .www.aerospaceweb.org2. 2. http://www.ansys.com/industries/aerospace_isl.htmhttp://www.ansys.com/industries/aerospace_isl.htm3. 3. http://www.aerospaceweb.org/question/weapons/q0261.shtmlhttp://www.aerospaceweb.org/question/weapons/q0261.shtml..4. 4. http://www.fluent.com/about/news/newsletters/00v9i1/a8.htmhttp://www.fluent.com/about/news/newsletters/00v9i1/a8.htm..5. http://www.fluent.com/solutions/articles/ja136.pdf5. http://www.fluent.com/solutions/articles/ja136.pdf

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