TEAM 12
P.V. PANEL WIND LOAD EFFECTS
Interim Review II
MARCH 2011
Arman Hemmati , Brady Zaiser,
Chaneel Park, Jeff Symons, Katie Olver
1
Overview
• Refresh
• Wind Tunnel Experiment Progress
• CFD Progress
Design Review #4: DeLoPREC
MARCH- 2011
2
Refresh
• Ideal angle of inclination is 51°
• Too much weight for the roof?
• Wind Tunnel testing – Experimental
• Computational Fluid Dynamics (CFD) - Computational
Design Review #4: DeLoPREC
MARCH- 2011
3
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
Design Review #4: DeLoPREC
MARCH- 2011
4
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
Design Review #4: DeLoPREC
MARCH- 2011
5
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
Design Review #4: DeLoPREC
MARCH- 2011
6
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
Design Review #4: DeLoPREC
MARCH- 2011
7
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
Design Review #4: DeLoPREC
MARCH- 2011
8
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
Design Review #4: DeLoPREC
MARCH- 2011
9
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
Design Review #4: DeLoPREC
MARCH- 2011
10
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
Design Review #4: DeLoPREC
MARCH- 2011
11
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
Design Review #4: DeLoPREC
MARCH- 2011
12
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
Design Review #4: DeLoPREC
MARCH- 2011
13
CFD - Update
• Pressure Coefficient
• Initially, CP > 1.5
• Now, CP < 1.1
▫ Biggest contributing factor: length of CV in front of panel
Design Review #4: DeLoPREC
MARCH- 2011
14
CFD - Verification
• Vertical Flat Plate
• Reference: “On the Flow of Air Behind an Inclined Flat Plate
of Infinite Span” -Fage and Johansen, 1927.
Design Review #4: DeLoPREC
MARCH- 2011
15
0.9
Pressure (Pa)
0.4
-0.1 13
13.5
14
14.5
15
15.5
Front
Back
-0.6
-1.1
-1.6
Design Review #4: DeLoPREC
Distance Along Y-Axis (m)
MARCH- 2011
16
CFD – Initial Results
Lift Coefficient Error (Exp. v.s.
Comp.)
100%
y = 2E-05x + 0.2511
75%
CD-ERROR [%]
CL-ERROR [%]
100%
Coefficient of Drag Error (Exp. v.s.
Comp.)
50%
25%
0%
0
20
40
60
a [degrees]
Design Review #4: DeLoPREC
80
100
y = -0.0004x + 0.2662
75%
50%
25%
0%
0
20
40
60
a [degrees]
80
100
MARCH- 2011
17
Design Review #4: DeLoPREC
MARCH- 2011
18
CFD – Initial Results
Design Review #4: DeLoPREC
MARCH- 2011
19
CFD – Next Step
• Determine why pressure increases with finer mesh
• Overcome convergence problems
• Try different solution models
Design Review #4: DeLoPREC
MARCH- 2011
www.ucalgary.ca/deloprec
Design Review #4: DeLoPREC
MARCH- 2011