Research Journal of Recent Sc Vol. 5(9), 51-56, September (20 International Science Community Associa CFD Analysis of Grid Fin A Z 1 CFD Rolls- R 2 Mechanical Eng Avai Received 6 th Jul Abstract This research paper gives outcome of a simulation to study the aerodynamics for b subsonic, supersonic and transonic flow composed of an external frame supporti Simulations are performed for a series of fin as well as the conventional planar fin. done in CAD software called Pro-Enginee ICEM-CFD. Further, the solving and pos Close conformity in results were seen for calculations within the region of the fin fo behaviour over the individual grid fins su characteristics and control effectiveness o higher pitching moments and lift forces to missile with grid/lattice fin arrangement g planar fins. The force along the axial direc planar fin missile. Keywords: CFD, Missile, Grid fin, Aerod Introduction Lattice fin is unusual control and lift surfac arrangement of flow channels something l shaped structure. The reason for choosin conventional fins is mainly due to its goo higher Mach number and freestream an disadvantage of the grid fin being choking of f in the transonic regime. The small chord of grid fins makes them les higher angle of attacks, permitting for agile Grid fins perform good at supersonic and whereas at transonic speed the performance drastically reduced. The air flow induces a nor form within the lattice, provoking the flow around the fin body producing a significant drag. However at higher Mach number values is completely supersonic and will provide less control than planar fins 1 . Grid Fin Application on Missile A grid fin which resembles a rectangular bo lattice structure. The grid is made by sma ciences _________________________________________ 016) ation Application on Missile in Superso Zubairkhan Kittur 1* and Amit Bahekar 2 Royce Division, QuEST Global Pvt. Ltd, Bengaluru, India gineering, Oriental University, Indore, Madhya Pradesh, India [email protected]ilable online at: www.isca.in, www.isca.me ly 2016, revised 18 th August 2016, accepted 25 th August 2016 study demonstrating a methodology for adopting comp ballistic missile with lattice fins and conventional fins at d regimes. A grid fin or lattice fin is normally unusual ing an internal grid of planar intersecting surfaces ha Mach number values and freestream angles between 0 to Modeling of unconventional grid fin missile and convent er Wildfire. The meshing of geometry is done using the pr st processing is done in Solver and Post-processor calle r both the cases. The simulation is also giving good resu or the higher freestream angles. The results were also cl ubjected under subsonic and supersonic regimes. Thus, th of grid fins can be observed unlike the conventional fins o overcome the drag forces, which are produced due to h generates greater normal force at diverse angles of atta ction of the grid/lattice fin missile arrangement was abou dynamics. ce with a paneled like a honeycomb ng grid fins over od performance at ngles. The major flow and high drag ss likely to stall at e turns in missile. d subsonic speed, of the grid fin is rmal shockwave to w to pass wholly t amount of wave s, the grid fin flow ser drag and higher ox which is full of all planar surfaces which are intersecting to create e shapes of either triangles or cube quite rigid and allows the lattice wa and also decreasing the weight o making it cheap for production. arranged in a perpendicular order a pass through cells of the lattice grid and are parallely aarranged to th Perhaps, at present the most well-k is on Russian medium range air 'Adder' 3 . Grid fin missile and its characte missiles reach the high supersonic s attractive within this speed regime the conventional or planar fins is Apparently due to this, it is very di at a high speed, due to the forces in of air passing through it. The miss servo mechanisms. This rotates a deflection angle. The magnitude of about its rotation axis dictates the s huge size of conventional or plana pressure to move over a larger ________E-ISSN 2277-2502 Res. J. Recent Sci. 51 onic Flow Regime putational fluid dynamics different flow regimes like control surface which is aving small chord length. o 25 degree for the lattice tional planar fin missile is re- processor named Ansys ed Ansys-CFX/ CFD-Post. ults for the flow structure lose in predicting the flow he enhanced aerodynamic s. Grid fins produce much higher angle of attack. The ack than compared to the ut 0.8 times higher than the each cells which are in the es. This box arrangement is alls to be very small and thin, of the materials and in turn A grid fin or lattice fin is allowing the freestream air to d but to the conventional fins he freestream air direction 2 . known appearance of grid fin to air missile called AA-12 eristics: After launching the speed. The grid fins are most e. But the main drawback of the long and wide surface. ifficult to move or turn them nduced by mass and quantity sile fins are turned by using and turns the fin to a new f torque taken to turn the fin ize of servos. The bigger and ar fins makes their centre of r vicinity. This movement
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Research Journal of Recent Sciences
Vol. 5(9), 51-56, September (201
International Science Community Association
CFD Analysis of Grid Fin Application on Missile in Supersonic Flow Regime
Zubairkhan Kittur1CFD Rolls- Royce Division, QuEST Global Pvt. Ltd, Bengaluru, India
2Mechanical Engineering, Oriental University, Indore, Madhya Pradesh, India
Available online at: Received 6th July
Abstract
This research paper gives outcome of a study demonstrating a methodology for adopting computational fluid dynamics
simulation to study the aerodynamics for ballistic missile with lattice fins and conventional fins at different flow regimes
subsonic, supersonic and transonic flow regimes. A grid fin or lattice fin is normally unusual control surface which is
composed of an external frame supporting an internal grid of planar intersecting surfaces having small chord length.
Simulations are performed for a series of Mach number values and freestream angles between 0 to 25 degree for the lattice
fin as well as the conventional planar fin. Modeling of unconventional grid fin missile and conventional planar fin missile i
done in CAD software called Pro-Engineer Wildfire. The meshing of geometry is done using the pre
ICEM-CFD. Further, the solving and post processing is done in Solver and Post
Close conformity in results were seen for both the cases.
calculations within the region of the fin for the higher freestream angles. The results were also close in predicting the flo
behaviour over the individual grid fins subjected under subson
characteristics and control effectiveness of grid fins can be observed unlike the conventional fins. Grid fins produce much
higher pitching moments and lift forces to overcome the drag forces, which
missile with grid/lattice fin arrangement generates greater normal force at diverse angles of attack than compared to the
planar fins. The force along the axial direction of the grid/lattice fin missile arra
planar fin missile.
Keywords: CFD, Missile, Grid fin, Aerodynamics.
Introduction
Lattice fin is unusual control and lift surface with a paneled
arrangement of flow channels something like a honeycomb
shaped structure. The reason for choosing grid fins over
conventional fins is mainly due to its good performance at
higher Mach number and freestream angles. The major
disadvantage of the grid fin being choking of flow and high drag
in the transonic regime.
The small chord of grid fins makes them less likely to stall at
higher angle of attacks, permitting for agile turns in missile.
Grid fins perform good at supersonic and subsonic speed,
whereas at transonic speed the performance of the grid fin is
drastically reduced. The air flow induces a normal shockwave to
form within the lattice, provoking the flow to pass wholly
around the fin body producing a significant amount of wave
drag. However at higher Mach number values, the grid fin flow
is completely supersonic and will provide lesser drag and higher
control than planar fins1.
Grid Fin Application on Missile
A grid fin which resembles a rectangular box which is full of
lattice structure. The grid is made by small planar surfaces