THE EFFECTS OF THE PLANFORM SHAPE ON DRAG ...mdx2.plm.automation.siemens.com/sites/default/files/...March 18-20, 2013 – Orlando, Florida (USA) THE EFFECTS OF THE PLANFORM SHAPE ON

March 18-20, 2013 – Orlando, Florida (USA)

THE EFFECTS OF THE PLANFORM SHAPE ON DRAG

POLAR CURVES OF WINGS:

FLUID-STRUCTURE INTERACTION ANALYSES

RESULTS

Aerospace Engineering

University of Pisa (Italy)

Speaker: Aerospace Engineer Matteo CIABATTARI [email protected]

Authors: M.R. Chiarelli, M. Ciabattari, M. Cagnoni, G. Lombardi

Relationship between Critical Conditions

and the component “U∞∙ cosΛ”

STAR Global Conference March 18-20, 2013

Orlando, Florida (USA)





AEROELASTIC ANALYSES OF TWO HALF – WING MODELS:

CURVED AND SWEPT PLAN - FORM

The curved plan-form causes a variable angle of sweep along the wing span, so, in

the transonic flight conditions wave drag effects are strongly reduced

The effects of the plan-form shape on drag polar curves (fixed values of CL) leads to

the reduction of CD of 7% - 10%

The curved plan-form configuration improves the wing’s aeroelastic behavior :

Analyses have been carried out by using STAR - CCM+® 6.04.14 and Abaqus® 6.11

in “co - simulation”

The reaction moments and stress values at the root of the curved wing are reduced by

about 5% - 8 %

Abstract



Index

1. Introduction

2. Rigid wing’ s model : STAR - CCM+® 6.04.14 CFD analyses

3. Elastic wing’ s model : Fluid - structure - interaction (FSI) analyses

STAR - CCM+® 6.04.14 and Abaqus® 6.11 “co - simulation”

4. Detailed analysis of rigid and elastic models results

5. Conclusions and future research activity







1.Introduction: Wings characteristic geometry Half wing area (S) = 239 m2

Aspect ratio (AR) = 7.53

Taper ratio (λ) = 0.119

Dihedral angle = 0°

Leading edge equation

y = -13316 x2 + 43519 x + 166

Supercritical airfoil NASA SC(02) 0410

Supercritical airfoil lies on planes

parallel to the longitudinal plane

of the wing half models

Not twisted airfoils along the half

span





2. Rigid wing’s model : STAR - CCM+® 6.04.14 CFD analyses

Volume of the aerodynamic field built in Catia® V5 R20

300,000 hexahedral cells around the wing

100,000 free cells in the far field





2. Rigid wing’s model : STAR - CCM+® 6.04.14 CFD analyses

Settings of the CFD model in STAR-CCM+® 6.04.14

Properties standard air H = 10,000 m

Density ρ = 0.4135 kg/m3

Static temperature T = 223.15 k

Static pressure p = 26,500 Pa

Kinematic viscosity ν = 0.92∙10-5 m/s2

Physic model set into STAR-CCM+® 6.04.14

Space → Three Dimensional

Motion→ Stationary

Time→ Steady

Material→ Gas

Flow→ Coupled (Momentum and Energy)

Equation of State→ Ideal Gas (Compressible)

Viscous Regime→ Turbulent

Reynolds-Averaged Turbulent→ k-ε Model



CFD analysis results between the two rigid wing models (CL= 0.4)



200 hours of CPU simulation ( 2 dual core personal computer with 8 GB RAM each one)





CFD analysis results between the two rigid wing models (CL= 0.4)

MACH CD RIGID

CURVED WING

CD RIGID

SWEPT WING ΔCD %

0.8 0.024 0.025 -4

0.85 0.026 0.029 -10

0.875 0.029 0.035 -17

0.9 0.036 0.045 -20



The CFD model and the FEM structural model must be perfectly complementary

in the areas where take place the exchange of the nodal forces and the

displacement nodal values: in Catia® V5 R20 an aerodynamic field that surround

the wing is constructed (slide n. 6)



3. “Co-simulation” : STAR-CCM+® 6.04.14 and Abaqus ® 6.11

Structural model of swept and curved wing has been built by using Catia ® V5 R20

Structural properties and dimensions have been assigned to the components

(SKIN, STRINGERS, RIBS, SPARS) in Abaqus® 6.11

Both models have the same dimensions for all their characteristic components

The results (static Aeroelastic analyses) do not take into account the distributions

of the structural or not structural weight: little influence on the deformation

shape of the wing at the examined flight conditions





3. “Co-simulation” : STAR-CCM+® 6.04.14 and Abaqus® 6.11











NUMBER OF STRUCTURE MESH ELEMENTS

CURVED WING 1,456

SWEPT WING 1,525

MATERIAL PROPERTIES (AL 7075)

DENSITY [kg/m3] 2,700

YOUNG MODULUS [MPa] 71,000

POISSON MODULUS 0.3

MASS OF THE HALF WING STRUCTURE [kg]

CURVED WING 10,203

SWEPT WING 10,125





500 hours of CPU “co - simulation” to obtain these results

Set in the CFD code STAR-CCM+® 6.04.14 an implicit unsteady analysis





500 hours of CPU “co – simulation” to obtain these results



Set in the CFD code STAR-CCM+® 6.04.14 an implicit unsteady analysis



ELASTIC

CURVED WING CD PRESSURE CD SHEAR CD TOT

NOSE 0.0081 0.0006 0.0087

UPPER SURFACE 0.0164 0.0019 0.0183

LOWER SURFACE -0.0015 0.0017 0.0002

Tot 0.0230 0.0042 0.0272

ELASTIC

SWEPT WING CD PRESSURE CD SHEAR CD TOT

NOSE 0.0111 0.0005 0.0116

UPPER SURFACE 0.0158 0.0018 0.0176

LOWER SURFACE -0.0015 0.0016 0.0001

Tot 0.0254 0.0039 0.0293

ΔCD PRESSURE % ΔCD SHEAR % ΔCD TOT %

NOSE -27.0 20 -25.9

UPPER 3.8 5.6 4

LOWER 0 6.2 0

Tot -9.4 7.7 -7.2

FLIGHT CONDITIONS : H = 10,000 m ; MACH = 0.85 ; CL = 0.4





The intensity of the shock wave on the curved wing is lower than the

intensity of the shock wave on the swept wing

Retardation of the boundary layer separation and an increase of aerodynamic

efficiency (E = L/D) of the wing









A comparison

of the in plant

shape and

position of the

wave front on

the two wings

upper surface





A comparison

of the in plant

shape and

position of the

wave front on

the two wings

upper surface





The sonic boundary, the red surface which enclose the supersonic region around

the wing, has a different shape and different dimensions comparing the swept

wing with the curved wing, especially toward the tip of the two wings


Front view: supersonic zone on

the upper surface of the two wings





Rear view: supersonic zone on

the upper surface of the two wings

The sonic boundary, the red surface which enclose the supersonic region around

the wing, has a different shape and different dimensions comparing the swept

wing with the curved wing, especially toward the tip of the two wings


















4. Detailed analysis of rigid and elastic model results

The Elasticity effects lower values of CL for fixed value of angle of attack






The Elasticity effects lower values of CD for fixed value of angle of attack






The drag polar curves CL - CD are quite similar for the two model elastic and

rigid wing

The CD0 value (drag coefficient corresponding to zero value of the lift) is not

influenced by the deformation effects, due to the reduction of the aerodynamic

loads along the span of the two wings






The estimated distribution of the aerodynamic load along the half span for

the two elastic wings: the resultant lift for the curved wing tends to move

inwards and this causes the reduction of moment characteristics at the root of

the wing box.






The results by the structural FE models of wings: at the clamped section

for the curved wing model the stresses are less of 5 % than the swept wing

model. It depends on the reduction of both the bending and torque moment

at the root of the wing.





5. Conclusion

Also taking into account the elasticity effect of the wing - box structure the

curved plan-form of a wing favorable influences both CP and MACH

distribution along the wing span

The results discussed in the present paper agree with previous results published

by the authors and confirm that the feasibility of the examined novel wing

configuration can be reach adopting standard design technology

Flight conditions: H = 10000 m ; CL =0.4 ; MACH = 0.85

The curved wing shows a reduction of CD of 7% than the swept wing

The structural bending moment and torsion moment of curved elastic model are

less of 5% : the stresses in the skin of the curved wing are less of 5%





The pressure rise across the shock wave is less intense and smoother in the

curved wing. The adverse pressure gradient towards the trailing edge is

reduced.

The separation of the boundary layer of the curved wing is delayed with respect

to the swept wing in transonic regime, with consequent beneficial effects on the

drag ( the aerodynamic efficiency tends to increase)



5. Conclusion



The plant shape of the shock wave front is strongly influenced by the shape of

the wings



5. Conclusion



The shape and dimensions of the supersonic zone around the wing

(the bubble zone) are strongly influenced by the shape of the wing: the

perturbation of the curved wing is less intense and then the energy dissipated in

the transonic phenomena around it reduces at same values of CL and MACH of

flight

Within the limits of a comparative study the result obtained confirm that, also

adopting a fluid - structure interaction procedure (FSI), the effects of the curved

plan-form configuration of a wing is not negligible from the aerodynamic point

of view in the transonic regime.



5. Conclusion

Dynamic response analyses ( Flutter Behavior) by using FSI analysis procedure :

“Co - simulation” by using STAR-CCM+® 6.04.14 and Abaqus® 6.11



Future research activity

Thanks to the “Co-simulation” by using STAR-CCM+® 6.04.14 and Abaqus® 6.11

It has been possible to examine with a good level of reliability a complex

Aeroelastic phenomena with minimum computational resources :

Only two Personal Computer with 8 GB of Ram each one



THE END (For the moment...)

Thank you



Prof. Eng. Mario Rosario CHIARELLI

(Aerospace Engineering - University of Pisa, Italy)

phone number:+390502217253

e-mail: [email protected]

Speaker: Aerospace Eng. Matteo CIABATTARI

phone number :+393284771319

e-mail: [email protected] or [email protected]



mailto:[email protected]















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THE EFFECTS OF THE PLANFORM SHAPE ON DRAG ...mdx2.plm.automation.siemens.com/sites/default/files/...March 18-20, 2013 – Orlando, Florida (USA) THE EFFECTS OF THE PLANFORM SHAPE ON