P.V. PANEL WIND LOAD EFFECTS

MARCH 2011

Arman Hemmati , Brady Zaiser, Chaneel Park, Jeff Symons, Katie Olver

Interim Review II

TEAM 12

MARCH- 2011Design Review #4: DeLoPREC

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Overview

• Refresh

• Wind Tunnel Experiment Progress

• CFD Progress

MARCH- 2011Design Review #4: DeLoPREC

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Refresh

• Ideal angle of inclination is 51°

• Too much weight for the roof?

• Wind Tunnel testing – Experimental

• Computational Fluid Dynamics (CFD) - Computational

MARCH- 2011Design Review #4: DeLoPREC

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Wind Tunnel – Where We Were

•Designed model in SolidWorks•Talked to Mike Johnson

▫Increase the thickness of adjustable support rods

▫Panel to be made from MDF•Machining to be done at faculty shop

MARCH- 2011Design Review #4: DeLoPREC

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Wind Tunnel – Building the Model

• Work order submitted February 4• Started work on February 22

▫ ½” MDF was unavailable substituted ¾”

• Picked up on Friday February 25• Some problems with design

▫ Filler on welded parts means that parts don’t fit together

▫ MDF panel is heavier than expected Need to do force analysis

MARCH- 2011Design Review #4: DeLoPREC

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Wind Tunnel – Budget

•Estimated cost of model▫Materials: ~$10

▫Labour: ~$25

▫Total: ~$35

•This is the only planned cost for our project•Extra costs may occur if something breaks

or we do further tests

MARCH- 2011Design Review #4: DeLoPREC

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Wind Tunnel – Force Measurement

•2 load cells measure lift force & pitching moment

•Drag plate measures drag▫Old springs & strain gauge were not stiff

enough▫Rebuilt with load cell

•Using LabView program to capture data▫3 data streams

MARCH- 2011Design Review #4: DeLoPREC

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Wind Tunnel – Wind Speed Measurement• Wind speed affects drag/lift force by:

FD or L = CD or L ∙ ½ ρv2A

• Cannot control speed in wind tunnel• Need to measure wind speed• Unable to capture digitally

▫Pressure too small for department’s pressure transducers

▫Hot wire anemometer fragile and expensive• Manually read dynamic pressure

▫Source of error▫Average not instant

MARCH- 2011Design Review #4: DeLoPREC

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Wind Tunnel – Testing Parameters

•Testing 3 parameters:▫Wind direction▫Panel angle▫Panel height

•Wind direction▫How does the force on the panel change

depending on the wind direction? Front, back

▫2 levels

MARCH- 2011Design Review #4: DeLoPREC

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Wind Tunnel – Testing Parameters•Panel angle

▫How does the force on the panel change as the angle increases?

▫In Calgary the ideal angle is 51°▫Testing at: 35°, 50°, 65° and 80°

▫4 levels

MARCH- 2011Design Review #4: DeLoPREC

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Wind Tunnel – Testing Parameters

•Panel height▫How does the force on the panel change as

the distance between the ground and the bottom of the panel increases?

▫Unable to use CFD for this▫ Testing at: 0, 1”, 2”, …, 6”

▫7 levels

MARCH- 2011Design Review #4: DeLoPREC

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Wind Tunnel – Testing Procedure

•How many runs?▫2∙4∙7 = 56 runs per replication▫2 replications = 112 runs

•Randomize run order▫Lots of set-up between runs

•How long will it take?▫5 min/run + daily set-up ▫Estimate 15 hours 1 week

MARCH- 2011Design Review #4: DeLoPREC

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Wind Tunnel - Schedule

•Behind schedule▫Hoped to test during reading week▫Machining took longer than anticipated

•Next 5 weeks:▫1 week testing▫1 week analysing results▫2 weeks further testing if necessary▫1 week preparing report

MARCH- 2011Design Review #4: DeLoPREC

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CFD - Update

• Pressure Coefficient

• Initially, CP > 1.5

• Now, CP < 1.1▫ Biggest contributing factor: length of CV in front of

panel

MARCH- 2011Design Review #4: DeLoPREC

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CFD - Verification

• Vertical Flat Plate

• Reference: “On the Flow of Air Behind an Inclined Flat Plate of Infinite Span” -Fage and Johansen, 1927.

MARCH- 2011Design Review #4: DeLoPREC

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13 13.5 14 14.5 15 15.5

-1.6

-1.1

-0.6

-0.1

0.4

0.9

FrontBack

Distance Along Y-Axis (m)

Pre

ssure

(P

a)

MARCH- 2011Design Review #4: DeLoPREC

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CFD – Initial Results

20 30 40 50 60 70 80 90 1000%

25%

50%

75%

100%

f(x) = − 0.000430477231319 x + 0.266165919788991

Coefficient of Drag Error (Exp. v.s. Comp.)

[ ]a degreesCD

-ER

RO

R [

%]

20 30 40 50 60 70 80 90 1000%

25%

50%

75%

100%

f(x) = 1.65071261752211E-05 x + 0.251118597093687

Lift Coefficient Error (Exp. v.s. Comp.)

[ ]a degreesCL-E

RR

OR

[%

]

MARCH- 2011Design Review #4: DeLoPREC

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CFD – Initial Results

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CFD – Next Step

• Determine why pressure increases with finer mesh• Overcome convergence problems• Try different solution models

MARCH- 2011Design Review #4: DeLoPREC

www.ucalgary.ca/deloprec