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