1
Flow around flapping wings with Open FOAM
at Aerodynamics, TU Delft
Hester BijlFrank Bos, Hans Bergers, Alex Loeven,
Bas van Oudheusden, Sander van Zuijlen, Aukje
de Boer
2
Study complex advanced aerodynamics for future of aerospace
Ups
trea
m/
Fund
amen
tal
Res
earc
h
App
lied
rese
arch
& s
ynth
esis
Applied
Aero
Plasma flow control (separation and
transition),BL
suction
Computational
Aero
Fluid-structure
coupling, Unsteady
flows, Uncertainty
quantif., Data assimilation
Experimental
Aero
Advanced Particle
Image Velocimetry, Unsteady
flows, Aeroacoustics
High-speed
flight
and re-
entry
vehicles
(EXPERT)Flapping
wings, Wind turbines, Aircraft
Future
aircraft,HP-sailplanes
4
Flapping wings I : Insects and Delfly -
understand and improve them using simulations-
RoboflyGeneric fly
5
Flapping-wing simulations: 2D flow (hovering and forward flight)
Periodic (top) and chaotic (bottom)
wake formation in forward flapping flight
6
• Solution of an by system.• Evaluation of times functions.
Create interpolation function s(x) through the known boundary displacements
Interpolation conditions: = known deformation of boundary (control) point
Required:
Mesh deformation with Radial Basis Function interpolation
s(x) = γ jϕ(| x − xb jj=1
nb∑ |)
s(xb j)
bn bnbninn
77
Moving airfoil comparing with
original method
Deformed mesh with Laplace smoothing and quaternions
Deformed mesh with RBF
Original
RBF
88
Moving airfoil: close up Smooth meshes with RBF
Deformed mesh with Laplace smoothing and quaternions
Deformed mesh with RBF
Original RBF
99
Deformed mesh with RBF
Deformed mesh with Laplace smoothing and quaternions
Original RBF
Moving airfoil: close up Boundary layer cells almost unchanged
with RBF
10
Flapping-wing simulation: 3D flow
vortex visualization around flapping 3D wing at low (top) and high (bottom) Rossby number
Flapping configurations:•
effect of stroke patterns•
effect of wing planform•
effect of Reynolds number•
effect of rotation (Rossby
nr)•
influence of deviation
11
Next : include deformation in the simulation
12
Flapping wings II : Galatea
12
13
Open Foam simulation of undulating fin
14
(not yet) Flapping wings III : Wind turbine airfoil and rotor
16
Preliminary test on a dummy rotor
Rotor radius 32m, V = 6 m/s, Ω=10rpm
OpenFOAM-1.5-dev :• Periodic boundaries
• k-ω SST turbulence model
• MRFSimpleFOAM: Incompressible NS
with multiple-reference frames
17
Full rotor simulations of the wind tunnel model
• Test case :• DU-96-W-180 airfoil
• Radius 1m, cmax =20cm, ctip =6cm
• V=5.98 m/s, Ω=400rpm
• Validation: Open jet wind tunnel and Fluent
• OpenFOAM simulations using MRFSimpleFOAM
18
Outlook : Open FOAM !
• Flapping wings : include deformation and clap and fling
• Wind turbine simulations : validate and include fluid-structure interaction, and control
• Plasma flow control : large eddy simulations with special actuation
• FSI in solidification: couple (accurately and efficiently) several domains
• Include uncertainty quantification and data assimilation, ….
19
Flow around flapping wings with Open FOAM
at Aerodynamics, TU Delft
Hester BijlFrank Bos, Hans Bergers, Alex Loeven,
Bas van Oudheusden, Sander van Zuijlen, Aukje
de Boer