Experimental Investigation of the Acoustic Field of a Realistic Wing Section with Slat and Flaps in High Lift Configuration

Transcription

1 Experimental Investigation of the Acoustic Field of a Realistic Wing Section with Slat and Flaps in High Lift Configuration Z. Patek C.Stoica V. Kopiev R. Abstiens 1

2 Possible sources of airframe noise vertical and horizontal tail clean wing slats flaps nose landing gear main landing gear 2

3 Structure Motivation Expertise on the numerical and experimental field Joint-Proposal for measurements at DNW-LLF Model deskription and wind tunnel set up Wind tunnel Measurement technique needed Other measurement technique used during the tests Proposed test program Requested test period 3

4 Numerical field 4

5 Slat-Wing Configuration (SWC) Investigations have been done in the framework of the national project FREQUENZ High-Lift devices Additional noise sources Lead to shorter and easier take-off and landing Finding a compromise requires the detailed understanding of the flow physics Large-Eddy Simulation (LES) Mach number Ma=0.16 Reynolds number Re=1.4*10 6 Angle of attack α=13 Provides: unsteady flow data starting point for acoustic analyses 5

6 Hybrid Method Turbulent boundary layer simulation CAA source terms from LES 6

7 SWC: LES Method and Mesh Compressible Navier-Stokes equations are solved by a 2 nd order finite-volume method Block-structured mesh with 32 blocks 55 million grid points approx x 280 x 65 Every 2 nd point Computational time was approx. 14 weeks on 32 CPUs (NEC SX8) Performance: 5.9 / 6.7 GFLOPS (avg. / max.), vector operation ratio of 99.6% 7

8 SWC: CAA Method and Mesh Solver: PIANO (German Aerospace Center, DLR) 1.8 million grid points 24 blocks highest resolved frequency is 8 khz 8

9 SWC: Generated Sound Acoustic sources in terms of the y-component of the perturbed Lamb vector L =(ωxv) Resulting pressure fluctuations 9

10 SWC: Possible Source Mechanisms Dipole noise due to slat trailing edge shear layer acoustic pressure interaction Main wing Slat Slat cove shear layer reattachment Reflection 10

11 EDGE - introduction Main CFD solver EDGE at VZLU It can be used in RANS, LES or DES mode Quantity of turbulence models are implemented Number of boundary conditions are implemented RANS mode with SST k-ω turbulence model is usually used at VZLU for external aerodynamics 11

12 Experimental field 12

13 TsAGI concept Corrugated edge for slat noise suppression Main idea: destruction of quasi-2d structure of the turbulence 13

14 Participation in other projects DLR AWB measurements The small-scale model with serrated edges was investigated in TsAGI anechoic chamber AK2 and DLR facility AWB in the FP7 project OPENAIR for small scales. 14

15 Participation in other projects TsAGI AK-2 measurements B&K Pulse system is widely used in TsAGI for acoustic measurements, including the work on current FP7 projects OPENAIR, VALIANT and ORINOCO 15

16 Noise measurements conducted in DLR AWB with different serration configurations 16

17 Noise measurements in TsAGI AK-2 have demonstrated that using serrated slats may lead to the reduction of noise by 8 db in the narrowband peak amplitude. Noise measurements conducted in AWB (DLR braunschweig) indicate that there are serration configurations (with negligible lift degradation at relevant angles of attack) that provide noise suppression in 1/3 octave spectra for all the directions in a wide frequency range. Narrow band analysis demonstrates that noise reduction is actually suppression of narrow band peaks which are located in this region (1.5kHz-7kHz). Actually, the best chevron slat suppresses the noise for all the narrow band components, distributed in the wideband region from 1.5 to 7 khz. 17

18 3 Seedingrakes were used QE-camera (higher sensitivity) separate calibration targets Remote control => laser and camera 2C-PIV measurements AWB/Frequenz 18

19 The model in the INCAS wind tunnel made from aluminum alloy (main wing) and stainless steel (movable flap) in order to enable low deformations under heavy loads, end plates are in wood. 19

20 Comparative aeroacoustic tests for take-off/landing configurations in open jet and close jet wind tunnels The influence of the model scale considering wind tunnel section. Reduction of boundary layer noise (the array may be covered with a layer of acoustic foam or placing the array behind a Kevlar cloth). The effect of wall reflections, which may have a bad influence over acoustic measurement in a closed test section. (The resulting source levels are different from corresponding levels in an open environment). The noise level of an array measurement versus single microphone measurement. A closer look at the areas where noise is generated (the fan, prechamber and experimental chamber). 20

21 Joint-Proposal for measurements at DNW-LLF 21

22 Main goal of the investigations Improving of aeroacoustic results in closed section wind tunnels. The tests will focus on the influence of the model scale in terms of aero acoustic. Development and validation of computational methods used by the partner, using representative results. Information from high speed PIV combined with acoustic measurements for validation of unsteady CFD computations. Better understanding of the flow physics behind the aero acoustic effects 22

23 Tasks AIA Project leader Measurements with 2C-PIV and/or TR 2C-PIV Support of the PIV measurements, data analysis processing of PIV results and preparing of reports CFD simulations with RANS - LES and Piano 23

24 Tasks VZLU CFD numerical simulations (EDGE and Star CCM+ software) acoustic numerical simulations (Star CCM+ software) CAD (CATIA, NX software) design processing of results and elaboration of reports 24

25 Tasks INCAS main part in this project will be aeroacoustic tests. provide a full system for aeroacoustic tests (sensors, data acquisition system and the software) contribute with 12 person months Financial support for the transport and insurance costs Analysis of acoustic data. processing of results and elaboration of reports 25

26 Tasks TsAGI Manufacturing of the slat with a number of replaceable edges with serrations compatible with the model used by the other partners Support for experimental investigations in the DNW-LLF with Bruel & Kjaer PULSE 3560D data acquisition system by a number of microphones Analysis of acoustic data, processing of results and elaboration of reports 26

27 Model description and wind tunnel set up A3XX-100 aircraft model X08D1 => some parts are lost FTEG model => actual status: no access A340 model => possible must be clarifyed! NEFA model 8PD => oportunity 27

28 Joint-Proposal for the DNW-LLF Location: DNW-LLF would be the optimal location for additional measurements with a high-lift wing configuration to validate the RANS-LES Solver and acoustic measurements in a closed test section Model: High-lift configuration with slat and flap configuration Measurement methods/locations: Acoustic measurements with microphone and/or microphone arrays to locate the noise source PIV-measurements at different positions on/at the wing section slat, slat cove (gap) and flap => high speed PIV 28

29 Wind tunnel measurement technique needed Pressure measurements techniques Acoustic measurement techniques 2C PIV-measurement techniques Other measurement technique used during the tests TR-PIV provided by AIA and/or DLR Göttingen Acoustic measurements by INCAS and TsAGI Timetable for the Preparation Definition of the measurement program according to the wind tunnel time 5/2012 Preparation and manufacturing of the additional slat configuration by TsAGI 10/

30 Proposed Testprogram => Must be defined depends on the type of model Requested test period DNW-LLF 3/2013 6/2013 Test of the measurement configuration the preparation phase (up to10 weeks) Wind on for up to 9 days setting variation combined with serrations (tunnel occupancy only for 12 days) Additional (financial) support could be provided by the German Research Foundation and Airbus when joining the consortium and also from the partner 30

31 Thank you for attention. 31