Interaction of fluidic actuators and a flat plate boundary layer: experiments and first results

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Kristian West
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KEIRSBULCK LAMIH UMR CNRS 8201 Valenciennes ONERA

1 Interaction of fluidic actuators and a flat plate boundary layer: experiments and first results Célestin OTT PhD student - 2 nd year ONERA Lille, LAMIH Valenciennes Thesis director: Laurent KEIRSBULCK LAMIH UMR CNRS 8201 Valenciennes ONERA Supervisor : Quentin GALLAS Onera Lille DAAA/ELV Funding: 50% ONERA & 50% LAMIH

2 Context v Flow control Boundary layer detachment wake turbulences Decreasing performances Energy losses Flow control Increase global performances by local manipulations Without flow control [1] [1] With flow control [1] J. Dandois, "contrôle des decollements par jet synthétique", PhD Thesis, ONERA,

metric of the effectiveness of a flow control solution v Association flow control

3 Motivation Zone of interest Continuous Pulsed Synthetic Sweeping v Highlighting dynamic mechanisms between jets and the turbulent boundary layer v Definition of a metric of the effectiveness of a flow control solution v Association flow control target à actuator configuration v Creation of a experimental data base for future CFD studies 3

Experimental approach v Select 2 configurations v Select & characterize 4 fluidic actuators v Characterization of the boundary layer v Measurement of the BL with control solutions v

4 Experimental approach v Select 2 configurations v Select & characterize 4 fluidic actuators v Characterization of the boundary layer v Measurement of the BL with control solutions v Space-time solved measurement : v PIV 2C&3C v LDA v Hot wire 1C v Pressure & shear measurement v Physical phenomenon analysis v PIV & Hot Wire maps investigations v Thorough analyses (POD, DMD) 4

5 Progress v Conception & fabrication hood (30x0.5mm² slot inclined at 45 ) Diffuser (3D printed) Sweeping jet actuator (3D printed) Flat plate with sensors Hot Wire Wall sensors 5

6 _ Characterization (1/4) v Wind tunnel characterization at 30m/s v v δ boundary layer thickness mm U δ = 99%. U I θ mommentum thickness (mm) M θ = K U L N U I 1 U L U I dy v c Q wall friction coefficient c Q = 2 1 KK ln RRRR X + CC [\ With K=0.384 et C=4.127 (Coles-Fernholtz formula) SSSSSS RRRR δδ(mmmm) θθ(mmmm) RRRR θθ cc ff uu ττ (mm ss) v u ] wall friction velocity u ] = U I c Q 2 FC PIV Wind tunnels almost identical. Comparisons possible 6

7 Characterization (2/4) v Characterization on test bench of continuous jet kit diffuser+ hood Hot wire measurements Homogeneity & Umax checked Relation P abcd & U dflgh Micro-manometer characterization relation VR <-> Palim 7

8 Characterization (3/4) v Characterization on test bench of sweeping jet Hot wire characterization Umean & F Relation P abcd & F, U ijk Hot Wire raw data (20 khz) 8

$m momentum coefficient C m = ρ ogpu \ ogp S ogp q d U ogp = 1 2 ρ IU \ 1 I S rgq 2 ρ IU \ I S rgq with$ : SS }~ test vein section Ujet mean velocity for continuous jet τ delay actuator signal jet τ=2.

: SS }~ test vein section Ujet mean velocity for continuous jet τ delay actuator signal jet τ=2.

9 Characterization (4/4) v Characterization in wind tunnel of pulsed & continuous jets (FESTO actuator) C m momentum coefficient C m = ρ ogpu \ ogp S ogp q d U ogp = 1 2 ρ IU \ 1 I S rgq 2 ρ IU \ I S rgq with : SS }~ test vein section Ujet mean velocity for continuous jet τ delay actuator signal jet τ=2.5 ms τ VelocityRatio FC sortie fente Evolution of C m = f w xyz w { Measurement of τ(ms) for experimental setup 9

10 First results (1/2) v Hot Wire measurement with continuous jet (VR2) Localizing the jet impact Hot wire scanning Transverse plane boundary layer profile at slot exit v Hot Wire measurement with pulsed jet (100Hz VR2) V Hot wire scanning Raw signal Average duty cycle phase lock Unsteady ponctual measurement BL profile with average DC Influence of frequency investigations 10

11 First results (2/2) [In progress] v PIV measurement time solved for pulsed jet v Quantronics Laser 1-10kHz 527nm 2x 19 mj v 2 Photron cameras 1024x1024 pixels 10kHz lens 105mm PROBLEM: No particles in the jet Jet too close to the wall 11

12 Exploratory PIV measurements v High Velocity Ratio (low middle veine velocity) v Low Velocity Ratio (high middle veine velocity) Wind Wind slot slot UU yy slot Up-wind streamlines control slot Wall friction control 12

Outlooks Short Term v Understand and characterize de two control types v Wall friction velocity investigations v Impact of the type of actuators used v Impact of VR and frequencies v Measurements

13 Outlooks Short Term v Understand and characterize de two control types v Wall friction velocity investigations v Impact of the type of actuators used v Impact of VR and frequencies v Measurements with synthetic and sweeping jet v Hot wire and 3C PIV measurements and investigations v Advanced analysis tools (POD & DMD)? v Actuators comparison Middle Term v Second test campaign (in process of definition) Onera 13

14 www. onera. fr

Flow control on a 3D backward facing ramp by pulsed jets

Acknowledgements: This work was carried out in the framework of the FOSCO project, supported by ic ARTS Flow control on a 3D backward facing ramp by pulsed jets 3 rd GDR Symposium P. Joseph a, D. Bortolus