CASE 1: TWO-DIMENSIONAL RANS SIMULATION OF A SYNTHETIC JET FLOW FIELD

CASE 1: TWO-DIMENSIONAL RANS SIMULATION

OF A SYNTHETIC JET FLOW FIELD

J. Cui and R. K. Agarwal

Mechanical & Aerospace Engineering Department

Washington University, St. Louis, MO 63130

OutlineOutline

1. Introduction2. Software Employed3. 2D Simulations of a Synthetic Jet Flow Field

Grid and Modeling Issues Results and Discussion

4. Conclusions of 2D Simulation Results5. Preliminary 3D Simulations of a Synthetic Jet

Flow Field6. Future Work

Motivation for Active Flow ControlMotivation for Active Flow Control In recent years, it has been surmised that the fluidic

modification of aerodynamic and propulsive flow fields can cover multiple flight regimes without the need of conventional control surfaces such as flaps, spoilers and variable wing sweep.

The fluidic modification (or flow control) can be accomplished by employing micro-surface effectors and other fluidic devices dynamically operated by an intelligent control system.

These new “flow control” technologies thus have the potential of resulting in radical improvement in aircraft performance and weight reduction.

Flow Control with Synthetic JetsFlow Control with Synthetic Jets

Virtual Aerodynamic Shape Modification of an Airfoil Using a Synthetic Jet Actuator (AIAA 03-4158)

Vectoring Control of a Primary Jet with Synthetic Jets (AIAA 02-3284)

Control of Recirculating Flow Region Behind a Backward Facing Step Using Synthetic Jets (AIAA 03-1125)

Interaction of a Synthetic Jet with a Flat Plate Turbulent Boundary Layer (AIAA 03-3458)

Flow Control of Shear Layers Over 2-D Cavities Using Pulsed Jet (AIAA 04-428)

CFD Flow-Solver EmployedCFD Flow-Solver Employed

WIND structured, multi-zone, compressible RANS solver 2nd or higher-order upwind/central differencing Four-stage Runge-Kutta time stepping Spalart-Allmaras (SA), Mentor’s SST, combined SST

& LES, and k-ε turbulence models

Grid EmployedGrid Employed

Whole view Zoomed in: the grid of the slot

Zone 1 (3386)

Zone 2 (6250)

Zone 3 (4165)

Zone 4 (197139)

Diaphragm

Boundary ConditionsBoundary Conditions

External Flow Region (zone 4)– Bottom wall (except SJ) no-slip – All other three boundaries outflow

SJ Actuator (zone 1, 2 & 3)– At the diaphragm arbitrary inflow– All other boundaries coupled or no-slip wall

At the Diaphragm (zone 1, I=1)

0),,( tconstyxv

tUtconstyxu sin),,(

constp

Justification of Boundary ConditionsJustification of Boundary Conditions

Mass-flux at the diaphragm & SJ slot Pressure inside the cavity

Phase-averaged v-velocity at (x, y) = (0, 0.1 mm)

Justification of Boundary ConditionsJustification of Boundary Conditions(cont.)(cont.)

Time-step & Grid Independence StudiesTime-step & Grid Independence Studies

Long-time averaged v-velocity along the centerline

Phase-averaged v-velocity at (0, 2mm)

Long-time AveragedLong-time Averaged v-v-Velocity Velocity along the Centerlinealong the Centerline

(a) v-velocity along the centerline (b) Zoomed-in view: near the wall

Long-time AveragedLong-time Averaged v-v-Velocity Velocity along along x-x-Axis Axis

y = 0.1mm y = 1mm

Averaged Jet Width & Phase-AveragedAveraged Jet Width & Phase-Averaged v-v-VelocityVelocity

phase, deg

y=0

.1m

m,v

,m/s

0 100 200 300

-20

0

20

PIVSSTHW

phase, deg

x=

1m

m,y

=2

mm

,v,m

/s

0 100 200 300

-20

0

20

PIVSST_LESSST

phase, deg

y=0

.1m

m,v

,m/s

0 100 200 300

-20

0

20

PIVSSTHW

phase, degy=

2m

m,v

,m/s

0 100 200 300-10

0

10

20

30

40

50SSTSST_0.5dtSST_Refined_Grid

phase, deg

y=0

.1m

m,v

,m/s

0 100 200 300

-20

0

20

PIVSSTSST_LESSAHW

Averaged jet width Averaged jet width Phase-averagedPhase-averaged vv--velocityvelocity

Phase-Averaged Velocity ContoursPhase-Averaged Velocity Contours

((uu at 45at 45))

PIV data SST SST_LES SA

2

4

8

-4

-432

1

-3

4

0

-70 -4

0

0

0

-8

7

0

0

1

1

2

0

2

1

7-7

1

3 -11

-1

-11

2

x, mm

y,m

m-2 0 2

0

1

2

3

4

5

6

7

8

u velocity contours at 45 deg

3

1

6

-6

-5

3

2

2

-34

1

-50 -3

0

1

0

-86

2

2

1

1

-1

-1

3

0

9-9

03 0

-1

1

-12

1

x, mm

y,m

m

-2 0 20

1

2

3

4

5

6

7

8


Phase-Averaged Velocity ContoursPhase-Averaged Velocity Contours((vv at 45at 45))


520 0

7

-3

26

9

2

30

19

328

30

28

22

30

2

3

9

4

1

51

1

113 4

1

50

1

2

11

1

1

x, mm

y,m

m-2 0 2

0

1

2

3

4

5

6

7

8

v velocity contours at 45 deg

4

10 0

4

-1

17

7

2

23

19

4

23

25 23

11

24

0

3

5

3

2

4

21

5

3

3

2

31

2

2

6

2

2

x, mm

y,m

m

-2 0 20

1

2

3

4

5

6

7

8


Phase-Averaged Velocity ContoursPhase-Averaged Velocity Contours((uu at 90at 90))


1

5

3

7

01

2

0

01

-1

-60-3

9

0

-4

7 -8

-1

-3

-6

-8

1

4

-5

8

-98

5

4 -4

2

0

-1 0

1

x, mm

y,m

m-2 0 2

0

1

2

3

4

5

6

7

8


27

6

7

-13

3

-1

-12

-1

-8-1

-4

4

1

-9

3 -3

1

-1

-3

-6

0

2

-3

9

-97

64

-4

1

1

-76

0

x, mm

y,m

m

-2 0 20

1

2

3

4

5

6

7

8




100

-1

9

019

2

1

27

9

-119

24

20

30

22

2-3

16

-1

-6

6

32

30

-3

-1

-7

61

0

-6

15

-3

-7

x, mm

y,m

m-2 0 2

0

1

2

3

4

5

6

7

8


210 -1

4

-1

17

4

0

22

8

013

19

15

29

17

1

-4

7

2

-2

4

22

23-4 -1

-8

32

2

-2

6

0

-5

x, mm

y,m

m

-2 0 20

1

2

3

4

5

6

7

8




-100 -1

15

14

-1

-1

12

-1

-2

1

4 1

16

5

1

0

21

1

-3

5

-4-3

21

0 2

0

8-5

-5

-3

30

-4

-1

x, mm

y,m

m-2 0 2

0

1

2

3

4

5

6

7

8


000 -1

9

1

4

-1

-1

10

0

-2

02

1

14

4

1

-2

19

-2

-6

3

-2-3

23

-3

0

-3

4-1

-5

-6

24

-6

-5

x, mm

y,m

m

-2 0 20

1

2

3

4

5

6

7

8



PIV data SST SST_LES SA-4

-30

-4

3

-3-7

-6

-11

-17

-9

-7

-12

-15 -14

-4

-9

-1

-2

3

-1

-1

2

-1-1

0-2 -1

-1

2-2

-1

-1

5

-1

-1

x, mm

y,m

m-2 0 2

0

1

2

3

4

5

6

7

8


-3-20

-3

4

-2

-5

-5

-9

-14

-7

-6

-10

-12

-11

-4

-8

-3

-1

6

-1

-1

3

-1-2

1

-1 -1

-1

1-3

-2

-1

8

-1

-1

x, mm

y,m

m

-2 0 20

1

2

3

4

5

6

7

8


Conclusions of 2D Simulation Conclusions of 2D Simulation Results

2D RANS simulations (SST, SST_LES, SA) and experiments have reasonable agreement in capturing the overall features of the flow field.

SST model gives the best result out of three simulations

Preliminary 3D SimulationsPreliminary 3D Simulations

Grids Modeling issues (same as in 2D simulations) Results and discussions

Grid EmployedGrid Employed

Whole view (9 zones) Zoomed in: the grid of the slot

Diaphragm Zone 2 (191951)

Zone 1 (731117)

Zone 3 (296135)

x

y

z

y

x

4

5

6

7

8

9

zone 4/8 5/9 6 7

# pts 39,525 31,875 165,075 133,125

Long-time AveragedLong-time Averaged vv-Velocity -Velocity along the Centerlinealong the Centerline

Long-time AveragedLong-time Averaged v-v-Velocity Velocity along along x-x-Axis Axis

y = 0.1mm y = 1mm

Averaged Jet Width & Phase-AveragedAveraged Jet Width & Phase-Averaged v-v-VelocityVelocity

Averaged jet width Averaged jet width Phase-averagedPhase-averaged vv--velocityvelocity

3

5

7

-3

-4

33

3

-2

3

2

-5

-1 -4

1

1

-1

-6 5

1

0

0

0

0

0

2

1

5-3

24 -2

0

1

-3 2

1

x, mm

y,m

m

-2 0 20

1

2

3

4

5

6

7

8


2

10 0

4

-1

23

6

2

27

16

4

24

28 28

15

28

2

3

6

4

2

5

4

3

53 4

2

32

3

3

5

3

3

x, mm

y,m

m

-2 0 20

1

2

3

4

5

6

7

8


Phase-Averaged Velocity Contours Phase-Averaged Velocity Contours ((u, vu, v at 45at 45))PIV data 2D SST 3D SST

u

v

Phase-Averaged Velocity Contours Phase-Averaged Velocity Contours ((u, vu, v at 90at 90))PIV data 2D SST 3D SST

1 -12

1

02

0

-50

-2

6

-2

-5

-5

-66

65 -5

0

x, mm

y,m

m

-2 0 20

1

2

3

4

5

6

7

8


0 0

15

1

25

7

021

24

3

0

30

0

x, mm

y,m

m

-2 0 20

1

2

3

4

5

6

7

8


u

v

Phase-Averaged Velocity Contours Phase-Averaged Velocity Contours ((vv at 135at 135, 225, 225))PIV data 2D SST 3D SST

000 0

9

2

4

0

-1

10

1

0

1

3 3

15

8

0

1

18

2

-1

6

0-1

21

1 3

0

6-2

-2

0

24

-1

0

x, mm

y,m

m

-2 0 20

1

2

3

4

5

6

7

8


-4-30

-4

2

-2

-5

-5

-7

-18

-8

-7

-11

-14

-13

-2

-8

0

-2

6

0

-1

3

1-1

2

-20

-1

1-1

-1

0

8

0

0

x, mm

y,m

m

-2 0 20

1

2

3

4

5

6

7

8


135135

225225

3D Simulation of Case1– 3D Simulation of Case1– u,v,wu,v,w Contours at 45 Contours at 45

3D Simulation of Case1– 3D Simulation of Case1– u,v,wu,v,w Contours at 90 Contours at 90

Future WorkFuture Work

3D simulations of case1: time-step and grid refinement study

3D simulations of case 2: synthetic jet interacts with cross flow

Documents

CASE 1: TWO-DIMENSIONAL RANS SIMULATION OF A SYNTHETIC JET FLOW FIELD