Aerodays 2011: Greening the air transport system REMFI. Rear fuselage and empennage flow investigation. Presented by Daniel Redondo / Adel Abbas

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1 Aerodays 2011: Greening the air transport system REMFI Rear fuselage and empennage flow investigation Presented by Daniel Redondo / Adel Abbas

2 REMFI - 6th Framework Programme - Partners Rear Fuselage and Empennage Flow Investigation

3 Aerodays REMFI REMFI: Main goals Improved computational p predictions for fuselage and tail design and analysis analysis. Enhanced understanding of the flow physics around the tails and rear end. Improved experimental p capabilities and measuring techniques for tail flows flows. WP1 Project management and coordination WP2 E Empennage i improved d controll surface f efficiency ffi i WP3 Sting mounting arrangement investigation WP4 Experimental verification study WP5 Innovative fuselage and empennage designs

4 WP2 Empennage improved control surfaces efficiency Prediction of gap effects Highly time consuming. Tendencies (Re, M, gap) well predicted (similar deltas values compared with WTT) The better aero solution is always the gap sealed one. Gaps geometry need to be perfectly represented (aircraft deformation needed) Reynolds effects on gaps are important. FUSELAGE/ELEVATOR GAP Sealed/Unsealed SHROUD GAP Always closed Elevator/rudder efficiency Small transition influence. Mach-dependence d more pronounced. Important influence of Reynolds number on results (till 15%) Good comparison between WT and CFD results in linear range. Better comparison at higher Re.

5 WP2 Empennage improved control surfaces efficiency Scaling methodology: Re effect CFD, WTT & SEM approach comparison Pseudo Reynolds effects indentified & studied: twin sting boom Cp good agreement Absolute drag not matched. Tendencies with better matching. Scaling methodology by scaling viscous drag and pressure drag separately RANS URANS DES Tail stall Improvements limited to delta effects Earlier stall with negative elevator deflection Mach=0.20, AoA=-22º, Re=38M, Fully turbulent Lift increased and drag reduced at high Re Stall delayed and lift enhanced with sealed fuselage gap (small influence) Earlytransition enhances lift and delays separation Small turbulence model influence, especially at high Re RANS mean values are consistent up to the stall Time accurate solutions necessary for post-stall

6 Aerodays REMFI WP3 Twin sting boom location effect Sting mounting arrangement investigation CFD capable of reproducing interference effects (RANS necessary) y) Wing downwash modified Shock induced separation and turbulence effects (strong Re dependency) Strong disturbance of supersonic flow around wing High sensitivity to TSR geometry and location (strongest at innermost position) Combination of advantages of experimental and numerical approaches delivers enhanced insight Standard Split Gap Split fuselage gap effect Labyrinth-type Split Gap Smooth dependence p of drag, g, lift and moment coefficients with M,, Re and angle of attack Fuselage flow field and gap flow field are quasi-independent for situations without deflection Insertion of deflection angle in the rear end generates a high crossflow through the gap, with major effect on the boundary layer. Internal gap recirculation Irrelevant effect of gap location Relevant suction effect with gap width due to recirculation Labyrinth gap reduces gap pressure correction

7 WP3 Methods for measuring / predicting wing deformation on twin sting models Sting mounting arrangement investigation SPT, ESPT and IPCT with very good agreement, but intrusive at high Re. HTP deformation with very small influence Rear balance deformation improves prediction accuracy Main wing deformation with very small influence IPCT coating SPT marker on Wing & HTP

8 Aerodays REMFI WP4 p Experimental verification studyy Moveable HTP Full-size Reynolds number tests HTP interface Twin sting Rear balance Classical wind tunnel tests

9 Aerodays REMFI WP4 Moveable HTP p Experimental verification studyy Remote control system for HTP motorization Very V high hi h lloads d High accuracy: setting accuracy 0.1º, measuring accuracy 0.01º Operation in cryogenic environment (-160º ( 160 C) Remote Control System for HTP Motor HTP i t f interface Pressure routing through complex HTP interface. Contionuous sealing system for criogenic conditions. Spring Loaded Support HTP Inclinometer Elevator/FuselageSealing Teflon/Spring Arrangement Sealing REMFI RC-System.MPG HTP/RC System Interface with Tubeless Pressure Connection Lever Arm PSI Scanner Load Bridge (HTP Interface)

10 WP4 Experimental verification study Twin sting New wing for cryogenic test and twin-sting boom adapters (3 for ARA, 1 for ETW) Rear balance Rear fuselage incl. Live-rear-end split plane Labyrinth sealing for fuselage split concept Standard split gap (1.45 mm) enlarged split gap (2.25 mm) and labyrinth sealing. Pressure measures for split plane Standard Split Gap Labyrinth-type Split Gap Fuselage split Labyrinth sealing

11 WP5 Innovative fuselage and empennage Innovative complete fuselage and empennage design Rear end length has shown optimum values with a lower fineness boundary Integrated belly fairing design results in drag reduction BF introduces a lift drop and drag increase with respect to fuselage-wing. No major improvements by a tangent intersection of the fuselage and belly fairing in the rear part. Integration with wing has the biggest potential for drag reduction. Increased volume near wing LE & TE improves the area ruling, but the volume near front of wing reduces the distance BF-engine and is detrimental. Onglets and fillets have been proven to reduce drag and delay separation. Prediction cabpabilities for thick boundary layer at rearend Better lift prediction than drag prediction (understimated) Different boundary layer models showed strong influence on the BL profile and thickness Best solutions seem to be obtained with different BL models for drag evaluation or boundary layer thickness for intlet/outlet behaviour. Turbulence models effect only onskin fi friction values Parametric evolution can be predicted with calculation (a refference experimental case could be sufficient)

12 WP5 Innovative fuselage and empennage Drag prediction and breakdown for fuselage and tail components g( ) Automatic adaptation needs reliable procedures Grid is the main source of differences on drag among the CFD code solutions Near field methods show good agreement among different CFD codes. Drag breakdown Wave drag (FF) Refined grid necessary along the chord at the shock (size/chord 0.5%) Adaptative meshing useful to reduce the number of cells. Induced d drag (NF and FF) Small influence of mesh size at the tip Friction or viscous drag (NF and FF) Usual boundary layer mesh desnsity is not enough. Pressure drag (NF) Refinement in the leading edge has an influence in spurious drag. Small geometries drag Onglet on HTP leads to drag reduction via pressure drag (NF) or induced drag (FF) Antenna on fuselage leads to drag increase via pressure drag (NF) or induced drag (FF) Fine grid (x3) Coarse grid Contributing cells to wave drag

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