Hoos Flying

2026-Present

Hoos Flying is UVA's SAE Aero Design team. Each year the team designs, builds, and flies a large-scale RC aircraft for the SAE Aero Design competition.

2026-2027

Aero Design Sub-Team

Run the team's ANSYS Fluent CFD on this year's blended wing body (BWB) concept: half model, steady RANS with k–ω SST, 35 ft/s at sea level.
Built a 12.95 M-cell mesh with 25 prism layers (first cell 0.02 mm), resolving the wall at y⁺ ≈ 1 (avg 0.34, max 1.38 at α = 0°).
Rebuilt the far field to 10 chords upstream and ≈19 downstream after the first, tight domain over-predicted lift.
Reported C_L = 0.572, L/D = 12.1 at α = 0° (converged) and C_L = 1.07, L/D = 7.3 at α = 10° (200-iteration mean of a cycling solution).
Presented the CFD updates at Hoos Flying meetings in LaTeX/Beamer decks.

Interactive Aircraft Model

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Setup

	ANSYS Fluent 2025 R2, half model
Solver	3D, double precision, pressure based, coupled, pseudo-transient; second order
Turbulence	k–ω SST, fully turbulent; inflow intensity 0.5%, viscosity ratio 10
Inflow	Velocity inlet on inlet and far field, 35 ft/s; at α = 10°, $(u, v, w) = (34.47, 0, 6.08)$ ft/s
Outflow	Pressure outlet, 0 Pa gauge
Symmetry	y = 0; no-slip walls
Mesh	12.95 M cells, 25 prism layers (first cell 0.02 mm); y⁺ avg 0.34, max 1.38 at α = 0°
Domain	10 c̄ upstream, ≈19 c̄ downstream, 5 c̄ above, below, and outboard

The body stays fixed; the freestream is rotated by α. Coefficients are normalized by the dynamic pressure $q = \frac{1}{2} ρ V_{\infty}^{2}$ and the half-model reference values:

C_{L} = \frac{L}{q S _{ref}}, C_{D} = \frac{D}{q S _{ref}}

Reference	Value	Note
$V_{\infty}$	10.668 m/s	35 ft/s
$ρ$	1.225 kg/m³	sea level
$S_{ref}$	0.7507 m²	half-model planform (full ≈ 2,327 in²)
$c_{ref}$	0.6452 m	mean aerodynamic chord; moments only

Forces in newtons don't depend on these settings; only the coefficients do.

Symmetry-plane mesh: fine near the aircraft, growing toward the far field.

Prism layers around the wing section — Prism layers wrapping the wing section.

Trailing-edge mesh close-up — Trailing-edge close-up.

Integrated Forces

C_L

C_D

L/D

Bars are the converged value at α = 0° and the 200-iteration mean at α = 10°; whiskers show the min–max range over the same 200 iterations. Hover a bar for its values.

	α = 0°	10° mean	10° range
$C_{L}$	0.572	1.068	0.79–1.18
$C_{D}$	0.0473	0.1475	0.136–0.183
L/D	12.1	7.3	4.6–8.3
Lift (full a/c)	13.5 lbf	25.1 lbf	18.5–27.7 lbf
Drag (full a/c)	1.11 lbf	3.47 lbf	3.20–4.31 lbf
$C_{m}$ , nose	−0.311	−0.493*	n/a

C_m about the nose. *Single snapshot at iteration 1,102; no moment history was recorded. At α = 10° the solution does not settle: lift and drag cycle roughly every 100 iterations, so the values are reported as means with their range.

Convergence

α = 0°α = 10°

Scaled residuals, α = 0° — α = 0°: residuals level off within ~100 iterations and stay flat.

Scaled residuals, α = 10° — α = 10°: a jump where the 10° inflow is applied to the warm start, then cycles with no further decay.

Pressure Coefficient

α = 0°α = 10°

Cp, centerbody, α = 0° — Centerbody (symmetry plane), α = 0°.

Cp, centerbody, α = 10° — Centerbody (symmetry plane), α = 10°.

Cp, blend section, α = 0° — Blend section, α = 0°.

Cp, blend section, α = 10° — Blend section, α = 10°.

Cp, outboard wing, α = 10° — Outboard wing, α = 10°: positive pressure along the whole lower surface.

Cp, planform plane, α = 10° — Planform plane, α = 10° (full aircraft, mirrored): low-pressure streaks trail both wingtips.

Flow from right to left in the section views. Color range: Cp from −1.5 to 0.9 at α = 0°, −1.5 to 1.0 at α = 10°. At 10°, a low-pressure pocket sits in the wake behind the centerbody and blend trailing edges, and is still visible about a chord downstream.

Cp, symmetry plane, full domain, α = 10° — Symmetry plane, full domain, α = 10°: the pressure disturbance fades well before the boundaries.

Velocity Magnitude

α = 0°α = 10°

Velocity, centerbody, α = 0° — Centerbody (symmetry plane), α = 0°.

Velocity, centerbody, α = 10° — Centerbody, α = 10°: a near-stagnant region over the aft upper surface and a thick wake.

Velocity, blend section, α = 0° — Blend section, α = 0°.

Velocity, blend section, α = 10° — Blend section, α = 10°: the low-speed region is thinner.

Velocity, outboard wing, α = 0° — Outboard wing, α = 0°.

Velocity, outboard wing, α = 10° — Outboard wing, α = 10°: a thin wake.

Velocity, planform plane, α = 0° — Planform plane, α = 0°.

Velocity, planform plane, α = 10° — Planform plane, α = 10°: a low-speed zone spans the centerbody trailing edge; fast flow around both wingtips.

Color range: 0–67.2 ft/s in the α = 0° sections (0–52.8 ft/s in its planform view), 0–58.9 ft/s at α = 10°. At 10° the peak, about 55–59 ft/s, sits just behind the leading edge on the upper surface.

Velocity, symmetry plane, full domain, α = 10° — Symmetry plane, full domain, α = 10°: the wake decays well inside the domain.

Vortex System

α = 0°α = 10°

Vorticity isosurface, α = 0° — α = 0°: a tip vortex trails from the wingtip; filaments shed where the wing trailing edge steps into the blend.

Vorticity isosurface, α = 10° — α = 10°: tip vortices much larger and stronger, with thick, coherent cores trailing from both tips.

Vorticity isosurface from above, α = 0° — α = 0°, from above: the speckled surface is boundary-layer vorticity, not separate vortices.

Vorticity isosurface, side view, α = 10° — α = 10°, side view: the cores rise from the tips as they trail downstream.

Vorticity isosurface, rear isometric, α = 10° — α = 10°, rear isometric.

Vorticity isosurface from below, α = 10° — α = 10°, from below.

Vortex tube at the blend trailing-edge step — α = 10°: a vortex tube sheds from the corner where the wing trailing edge meets the blend.

Blend trailing-edge step, second angle — Same feature, looking along the trailing edge; the tube is colored ≈20–35 ft/s.

Isosurfaces of vorticity, colored by velocity (0–70 ft/s at α = 0°, 0–60 ft/s at α = 10°).