Delta-Wing Vortex Lift Enhancement Using Oblique Channel Distribution

Advisor: Dr. McClain Project Manager: Meag McNaryRuben Nunez

Adam EakerRyan Parker

Drew Waggoner

ME LAB 4335- Final Presentation

OverviewInitial ObjectiveFinal ObjectiveTheoryExperimentationSchedule SummaryResultsSignificanceSummaryRecommendationsQuestions

Initial ObjectiveQuantify the steady flow effects of oblique

element distributions interacting with vortical structures attached to a delta wing micro unmanned air vehicle

Areas of interest:High angle of attackRoughness elementsLift and Drag

Final ObjectiveQuantify the steady flow effects of obliquely

aligned channels interacting with vortical structures on a delta wing micro unmanned air vehicle

Areas of interest:High angles of attackLow Reynolds Numbers Obliquely aligned channelsLift and Drag

Theory – Delta Wing

Theory – Vortex BehaviorUnpredictable behavior

Leading-edge vortices Induces additional lift by pressure decrease

on suction surface

Vortex breakdown Vortex expands into highly fluctuating structure Induced by high angles of attack or pressure rise Vortex separates from wing Disadvantages:

Wing fluttering Loss of performance Decrease in lift

Vortex Breakdown

Delay bursting of vorticesIncreases performance

Controlled by increasing ωθ and induce secondary flow

Methods:Mechanical

Local action by contouring surfacePneumatic

Introduce perturbations through air flow

Theory – Vortex Breakdown Control

Obliquely aligned elements

Vθ

VL

Leading-edge separation line

Vortex separation line reattachment line

Control elementregion

Jet FlapsLeading or Trailing edge

Can be difficult to implement.

Leading edge: + large increase on lift,- large increase on drag.

Trailing edge:+ increase stability - small increase on lift,

Piezoelectric StripsBonded on delta wing for

active control of oscillations.

Serve as sensors and actuators.

Voltages applied across strips create forces to counter oscillations.

Lightweight, cheap, and easy to manufacture.

Obliquely Aligned ElementsElements prevent

breakdown of vortices by directing air flow and produce high lift forces.

Elements also prevent buffeting and oscillations.

Moderate drag penalty.

Leading-edge separation line

Vortex separation line reattachment line

Control elementregion

Obliquely Aligned ChannelsDesigned to stabilize

the vortical flow.

Restrict pressure rises that precipitate breakdown.

Increase ωθ and induce secondary flow

Promote Reattatchment

ExperimentationSet up to determine the lift and drag coefficients on

a Delta Wing with varying angles of attackMeasurements:

Data Acquisition LABVIEW

Angle of Attack (0° to 45°) Using a set screw to adjust attack angle in 5° increments

Lift and Drag Force Force Balance

Static Pressure Difference Using a Pitot-Static Tube and

the PCL2A

Delta Wing

Wind Direction

Test Section

WIND TUNNEL

Figure 1: Wind tunnel experiment set-up to determine lift and drag coefficients on a Delta Wing with a fixed wind velocity.

Initial Schedule Summary

Preliminary Data Collection

Test Plan Due

Develop Connector Piece

Develop Rotating Mechanism

Printing of Delta Wings

Data Collection

Final Presentation

Final Project Due

2/6/20

11

2/16/2

011

2/26/2

011

3/8/20

11

3/18/2

011

3/28/2

011

4/7/20

11

4/17/2

011

4/27/2

011

5/7/20

11

Final Schedule Summary Preliminary Data Collection

Research

Test Plan Due

Work on Report

Develop Connector Piece

Develop Rotating Mechanism

Manufacturing of Delta Wings

Data Collection

Final Presentation

Final Project Due

6-Feb 16-Feb 26-Feb 8-Mar 18-Mar 28-Mar 7-Apr 17-Apr 27-Apr 7-May

Results

0 5 10 15 20 25 30 35 40 45 500.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

Coefficients of Lift and DragRe=179,260 V=15.09m/s

Smooth CLSmooth CDChanneled CLChanneled CD

Angle of Attack (deg)

Coeff

icie

nts

of L

ift

and

Dra

g

Results

0 5 10 15 20 25 30 35 40 45 500

1

2

3

4

5

6

7

8

9

Lift/DragRe=179,260 V=15.09m/s

SmoothChanneled

Angle Of Attack

L/D

ResultsOverall trend is the same for both wings

Lift and drag are less in the channeledIncreased difference in lift just before stall

Stall occurred at approximately 35°Lift after stall was greater for the channeled

SignificanceOblique channels do not increase

performanceThe effects after stall might suggest

improvement is possible

SummaryThere are multiple ways to manipulate the

vortical breakdownMechanicalPneumatic

Channeled wing does not drastically increase performanceLift force reducedDrag force reduced

RecommendationsImprovements in the channeled design might

allow for better performance than current model

Test at higher Reynolds numbersResume original test criteria

Oblique elemental distributions

Arrangement of the distributions

Questions?