Reusable Rocket Booster 3×3 Lattice Grid Fin Normal Force & Braking Drag

Launch Vehicle External Aerodynamics (CFD)PASS · 1.13%

Aerodynamic braking drag, normal control lift force, and inter-cell channel flow acceleration for a 3×3 cellular titanium rocket grid fin at 12° angle of attack.

Tolerance:: 5%

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Problem statement

Geometry: Virtual wind tunnel 680 × 440 × 440 mm enclosing a 230 × 230 × 55 mm 3×3 honeycomb lattice grid fin (12 mm frame, 10 mm internal webs, 9 open 62 × 62 mm cells, and root actuator lug) pitched at alpha = 12°.
Material: Air at 20 °C (rho = 1.204 kg/m³, mu = 1.825e-5 Pa·s).
Boundary conditions: Inlet velocity U = 65.0 m/s along +X, outlet gauge pressure 0 Pa, outer tunnel walls slip symmetry, all 50 internal grid-fin frame and web surfaces viscous no-slip walls.
Measured quantity: Braking drag coefficient CD (target 2.250 from lattice wing blockage theory, computed 2.275, FD = 169.50 N) and positive control lift force FL = 19.23 N (CL = 0.258).

WebCAE Terminal

Paste these commands into the Terminal panel inside WebCAE. They use the same text DSL as the application; run one command per line:

units mm
import path="cfd_grid_fin_aerodynamics.step" format=step
mesh tet size=28
cfd fluid air
cfd set mode=steady speed=65.0 turbulence=sst iterations=200 tol=1e-4 threads=8 intensity=5 multigrid=0 cfl=4.0
cfd inlet surface number 1 speed=65.0 intensity=0.05
cfd outlet surface number 6 pressure=0
cfd symmetry surface number 2
cfd symmetry surface number 3
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cfd wall surface number 7 monitor=on
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solve cfd

Results comparison

Reference value	2.250
Our result	2.275
Deviation	1.13%
Tolerance	5%
Status	PASS · 1.13%
Element family	Finite-volume CFD
Mesh details	5074 узлов, 21661 тет (Netgen P1 tet mesh, решётчатый аэродинамический руль 3×3 ракеты-носителя)

Updated: 2026-10-19 · WebCAE 0.2.0 · 54751b2e+dirty