TECHNICAL'REPORT ECOM C-0423-1 (Q GASEOUS PLUME DIFFUSION (0: CHARACTERISTICS WITHIN MODEL PEG CANOPIES 0 TASK IIB RESEARCH TECHNICAL REPORT *e DESERET TEST CENTER 0* BY S * R. N. MERONEY D. KESIC .' * and * T. YAMADA FE 0SEPTEMBER 1968 ~DISTRIBUTION OF THIS DOCUMENT IS UNLIMITED UNITED STATES ARMY ELECTRONICS COMMAND FORT MONM .OUTH, N. J. CON-.-RACT DAAB07=68=C=0423 FLUID DYANAMICS AND DIFFUSION LABORATORY FLUID MECHXICS PROGkAM COLLEGE OF ENGINEERING COLORADO STATE UNIVERSITY ... - FORT COLLINS, COLORADO 80521 0I
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
TECHNICAL'REPORT ECOM C-0423-1
(Q GASEOUS PLUME DIFFUSION
(0: CHARACTERISTICS WITHIN MODEL
PEG CANOPIES
0 TASK IIB RESEARCH TECHNICAL REPORT
*e DESERET TEST CENTER
0* BYS
* R. N. MERONEYD. KESIC .'
* and
* T. YAMADA FE
0SEPTEMBER 1968
~DISTRIBUTION OF THIS DOCUMENT IS UNLIMITED
UNITED STATES ARMY ELECTRONICS COMMAND FORT MONM .OUTH, N. J.
CON-.-RACT DAAB07=68=C=0423FLUID DYANAMICS AND DIFFUSION LABORATORYFLUID MECHXICS PROGkAMCOLLEGE OF ENGINEERINGCOLORADO STATE UNIVERSITY ... -
FORT COLLINS, COLORADO 80521
0I
BL7 A.iiow
I .. ,**DISCLAIMER
~-.~jT EiTATION OF TRADE NAMES AND NAMES OF MANUFACTURERS IN THIlS REPORT
IS NOT TO BE CONSTRUED AS OFFICIAL GOVERNMENT INDORSEMENT OR APPROVAL
OF COi.iERCIAL PRODUCT'S OR SERVICES REFERENCED) HEREIN.
4
Technical Report ECOM C-0423-1 September 1968
Wind Tunnel Studies and Simulations
of Turbulent Shear Flows Related to
Atmospheric Science and Associated Technologies
TECHNICAL REPORT
GASEOUS PLUME DIFFUSION
CHARACTERISTICS WITHIN MODEL
PEG CANOPIES
TASK IIB RESEARCH TECHNICAL REPORT
DESERET TEST CENTER
PREPARED BY
R. N. MERONEY
D. KESIC
and
T. YAMADA
Fluid Dynamics and Diffusion Laboratory
Fluid Mechanics Program
College of Engineering
Colorado State University
Fort Collins, Colorado
80521
for
ATMOSPHERIC SCIENCES LABORATORY
U. S. Army Electronics Command
Fort Monmouth, N. J.
CER68-69RNM-DK-TY-3
ABSTRACT
A point source of an air-helium mixture was released
continuously at various positions within a simulated canopy composed
of 9 cm high pegs, 0. 48 cm diameter, spaced in several arrays
(2.54 x 2.54, 3.55 x 3.55, and 5.08 x 5.08 cm). Variations of the
vertical location of the source revealed the strongly nonisotropic
character of diffusion within a canopy with respect to the relative
diffusion rates in the lateral and vertical direct; ns. When the source
was placed at various downstream distances from the edge of the can-
opy, it displayed a tendency to exhale the plume near the front of the
model canopy and to inhale the plume at distances further downstream.
Calculations of the turbulent diffusion coefficient, K, within and above
the canopy from the experimental data, reveal both a constant region
and a region of linear increase with height increase as suggested by
1 Wind tunnel and artificial canopy configuration ......... 24
2 Continuous point source feed and sampling system..... .25
3 Velocity profiles within model canopy ................ 26
4 Velocity profiles above model canopy .............. 27
5 Longitudinal turbulent intensity for model canopy .. .. 28
6 Vertical turbulent intensity for model canopy .......... 29
7 Shear profile for model canopy. . . . . . ......... 30
8 Streamline flow in and above a model canopy. . . . . . 31
9 Vertical dispersion of a continuous point sourcein a model peg canopy (2. 54 x 2. 54 cm) x =0,z - 1cm . . . . . . . . . . . . . . . . . . .. . . . . . .. . 32
s
10 Vertical dispersion of a continuous point source ina model peg canopy (2. 54 x 2. 54 cm). x5 = 0z =-0. 5 h . . . . . . . . . . . . . . . . .. . . . . . . .. . 33
s
11 Vertical dispersio A a continuous point sourcein a model peg canopy (2. 54 x 2. 54 cm). x - 0,z = h . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
12 Vertical dispersion of a continuous point sourcein a model peg canopy (2. 54 x 2. 54 cm). x 6 m,zs lcm . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
13 Vertical dispersion of a continuous point sourcein a model peg canopy (2.54 x 2.54 cm). x 6 m,
S
14 Vertical dispersion of a continuous point source ina model peg canopy (2. 54 x 2. 54 cm). x 6 1,
iv
I
LIST OF FIGURES - Continued
Figure Page
15 Lateral dispersion of a continuous point sourcein a model peg canopy (2. 54 x 2. 54 cm). x = 6 m,z 1 cm. ........................... 38s
16 Lateral dispersion of a continuous point sourcein a model peg canopy (2. 54 x 2. 54 cm). x = 6 m,5z =h .............................. . ........ . 39s
17 Lateral dispersion of a continuous point sourcein a model peg canopy (2. 54 x 2.54 cm). x z 6 m.z = 1 cm ............ ................. ...... . 40s
18 Lateral dispersion of a continuous point sourcein a model peg canopy (2. 54 x 2. 54 cm). x = 6 m,5z =h . . . . . . . . . . . . . . . . . . . . . . . . . .. 41
s
19 Vertical dispersion of a continuous point sourcein a model peg canopy (2. 54 x 2.54 cm diagonal).x = 0. z = 1 cm . . . . . . . . . . . . . . . . . . . . . . 42
5 5
20 Vertical dispersion of a continuous point sourcein a model peg canopy (2. 54 x 2.54 diagonal).x s =00 z s= 0.5 h .. .. .. .. .. .. .. .. .. . .. 43
21 Vertical dispersion of a continuous point sourcein a model peg canopy (2. 54 x 2. 54 diagonal).x =0, z =h . . . . . . . . . . . . . . . . . . . .. . . 44
22 Vertical dispersion of a continuous point sourcein a model peg canopy (2. 54 x 2.54 diagonal).x -6 m. z z--lcm . . . . . ......... 0 . ... 45
23 Vertical dispersion of a continuous point sourcein a model peg canopy (2. 54 x 2. 54 diagonal).x 6 m, z 0.5h . ................... 46
24 Vertical dispersion of a continuous point sourcein a model peg canopy (2. 54 x 2. 54 diagonal).x -6 m, z -h . . . . . . . . . . . . . . . . . . . . . . 47
25 Vertical dispersion of a continuous point sourcein a model peg canopy (2. 54 x 2. 54 diagonal).x s 6m, z - l. Sh . ............... . . . . . . 48
s 5
V
LIST OF FIGURES - Continued
Figure Page
26 Vertical dispersion of a continuous point sourcein a model peg canopy (5. 08 x 5. 08 cm). x = 0,Sz = 1 cm, x = 0.3 m ...... ..................... 49
s
27 Vertical dispersion of a continuous point sourcein a model peg canopy (5.08 x 5.08 cm). x = 0,s
z s1=cm, x = 0.6m ..... ................... .50s
28 Traces of maximum concentration from a pointsource (2.54x 2.54 cm). x = 0, z = 0.5h ........ 51
29 Traces of maximum concentration from a pointsource (2.54x2.54cm). x =0, z =h . . . . . . . . . .52
30 Diliusion in the canopy-isoconcentration lines(2.54x 2.54 diagonal). x = 0, z = 1 cm. . . . . . . . . .53s 5
31 Diffusion in the canopy-isoconcentration lines(2.54x 2.54 diagonal). x -=0, z = 0.5h . . . . . . . . .54
32 Diffusion in the canopy-isoconcentration lines(2. 54 x 2. 54 diagonal). xs %. 0, z -- h . . . .. . ..... 55
33 Duflusion in the canopy-isoconcentration lines(2.54x 2.54 diagonal). x = 6, z 8= crn . .. ... . * * .56
34 Diffusion in the canopy-isoconcentration lines(2.54x 2.54 diagonal). x 8 x 6. z a 0.5 h * . s ... . . .57s s
35 Diffusion in the canopy-isoconcentration lines(2.54x 2. 54 diagonal). x 8 6, z w h ••....... .58s s
36 Diffusion in the canopy-isoconcentration lines(2,54 x 2.54 diagonal). x s a 6. 2 1.5h. . . . . . . . . .59
J? Gaseous plume cross-section of a continuouspoint source in a model peg canopy (2. 54 x ?. 54 cm).x a 6 m, z. 2 1 cm, x r 0.3 m . . 0 * .. . .. . . . # 60
38 Gaseous plume cross-section of a continuouspoint source in a model peg canopy (2. 54 x 2. 54 cm).x a6m, z : h. x 0. 3 m . . . . . . . . . . . . . . . . .61
S v
vi
4,
LIST OF FIGURES - Continued
Figure Page
39 Gaseous plume cross-section of a continuouspoint source in a model peg cano -" (2. 54 x 2. 54cm diagonal). x = 6m, z = 1 cm, x = 0.25m . . .. 62
5 S
40 Gaseo-:.- plume cross-section of a continuouspoint source in a model peg canopy (2. 54 x 2. 54cm diagonal). : C -, z = h, x = 0. 5m . . . . 63S 5
41 Gaseous plume cross-section of a continuouspoint source in a model peg canopy (5.08 x 5.08cm). x = 0 m, z = 1 cm, x = 0.3 m . . .... ...... 64
42 Gaseous plume cross-section of a continuouspoint source in a model peg canopy (5.08 x 5.08cm). x = 0m, z =1 cm, x= 0.6m . . . . . .. .. . 65
Ihe resulting profiles in K(z) are displayed on Fig. 45.
Three distinct regions of variation of K are noticeable. Immedi-
ately adjacent to the wall is a zone where K increases exponentially.
In the area from 2 to 5 cm, K remains essentially constant; and,
finally, K increases linearly with z in the region beyond 5 cm.
A number of authors have suggested that K should remain
constant in vegetative cover; others have suggested that K should
vary linearly. 2,3 It is interesting to note that for the case of the
model peg canopy, both conditions of K exist, although in different
regions. Figure 47 compares the distribution of K within the canopy
with typical results of the distribution of K for a corn crop as
measured by Uchijima and Wright.
The momentum vertical eddy transport coefficient K hasm
been calculated from the velocity and shear data found in Reference
18 by use of
K -(d) (3)
m d
18
Figure 46 compares the variation of the momentum, K and massm
K eddy diffusion coefficients in and above the artificial canopy.c
Above the canopy, K becomes proportional to ( z-d ) where d is
a displacement height. Similar behavior has been observed for
prototype canopies. 1, 2, 3,12,13, 21
As a result of calculations by Denmead, the eddy diffusivity in
a pine forest might also be interpreted to behave in a similar man-21
ner. Wright and Lemon reported K distributions in a canopy of
corn; however, they reported results in terms of a wind profileclassification which does not permit direct comparison. 22 Finally,
these K profiles may also be described as qualitatively similar to
the peg data.
19
CONCLUSIONS
It is apparent that the general character of flow in and above
vegetative canopies may be satisfactorily simulated in the meteorolog-
ical wind tunnel. In addition, these new data suggest that even the
micro-sctucture transport phenomena behave in a manner similar to
that of the prototype. Therefore, it is possible to conclude that:
1) The basic trends of the dynamic and kinematic behavior of a
complex vegetative cover may be simulated by a simple porous
geometry in a wind tunnel.
2) The initial fetch of the peg canopy affects tracer dispersion
of a continuous point source in a unique manner: Vertical convective
motions exhale the gases released at the beginning of the canopy, and
subsequently, the canopy appears to re-inhale the products farther
downstream.
3) The dispersive characteristics of the canopy are non-
isotropic. For a source near ground level, lateral mixing is strong;
for a source located at the top of the canopy, vertical transport
predominates.
4) The eddy diffusion coefficient varies linearly as (z-d)
above a vegetative cover and has a growth rate proportional to ku*.
5) The eddy diffusion coefficient, K , within the artificial
vegetative cover, appears to develop into three regions: Initially K
r20
grows exponentially, next it remains constant, and, finally, K grows
at a linear rate,
6) The experimental law for attenuation of boundary concen-
-2.5tration was obtained as x for gas source releases far from the
canopy inception. (Rates of dispersion are somewhat larger near the
edge of the vegetative cover.)
21
BIBLIOGRAPHY
1. Penman, H. L. and I. F. Long, "Weather in Wheat," Quarterly
Journal of Royal Meteorological Society, Vol. 86, pp. 16-50,1960.
2. Inoue, E., "On the Turbulent Structure of Airflow Within CropCanopies, " Journal of Meteorological Society of Japan, Series11, Vol. 41, #6, December 1963.
3. Uchijima, Z. and J. L. Wright, "An Experimental Study of AirFlow in a Corn Plan-Air Layer, " Bulletin of the NationalInstitute of Agricultural Sciences (Japan), Series A, #11,February 1964.
4. Lemon, E. R., (ed.), "The Energy Budget at the Earth's Surface,"Part II, Production Research Report No. 2, Agricultural ResearchService, U. S. Dept. of Agriculture, 49 p, 1962.
5. Bayton, H. W. "The Penetration and Diffusion of a Fine Aerosolin a Tropical Rain Forest, " Ph. D. Thesis, University ofMichigan, Ann Arbor, 1963.
6. Raynor, G. S., "Effects of a Forest on Particulate Dispersion,USAEC Meteorological Information Meeting, Chalk River,
Canada, September 1967.
7. Plate, E. J. and A. A. Quarishi, "Making of Velocity DistributionsInside and Above Tall Crops, " Journal of Applied Meteorology,Vol. 4, #3, pp. 400-408, June 1965.
8. Yano, Motoaki, " Turbulent Diffusion in a Simulated VegetativeCover, " Fluid Dynamics and Diffusion Laboratory Tech. Rept.CER66MY25, Colorado State University, 1966.
9. Hidy, G. M., (ed), "On Atmospheric Simulation: A Colloquium, I
NCAR Technical Note NCAR-7N-22, Boulder, November 1966.
10. McVehil, G. E., et al., "On the Feasibility of Modeling SmallScale Atmospheric Motions, " Cornell Aeronautical Laboratory,Tech. Rept. ZB-2328-P-1, April 1967.
22
11. Plate, E. J. and J. E. Cermak, "Micro-Meteorological WindTunnel Facility: Description and Characteristics, " FluidDynamics and Diffusion Laboratory, Tech. Rept. CER63EJP-JEC 9, Colorado State University, 1963.
12. Saito, T., "On the Wind Profiles in Plant Communities,"Bulletin of the National Institute of Agricultural Science (Japan),Series A, #11, February 1964.
13. Cionco, R. M., W. D. Ohmstede and J. F. Appleby, "Model forWind Flow in an Idealized Vegetative Canopy, " Report ERT)AA-MET-7-63, Electronics Research and Development Activity,Ft. Huachuca, June 1963.
14. Schlichting, H., Boundary Layer Theory, McGraw Hill Book Co.,Inc., New York, 1960.
15. Tourin, M. H. and W. C. Shen, "Deciduous Forest DiffusionStudy, " Final Report to U. S. Army, Dugway Proving Grounds,Contract DA42-007-AMC-48(R), August 1966.
16. Allison, J. K., L. P. Herrington and J. P. Morton, "DiffusionBelow and Through a Dense, High Canopy, " Paper PRC 68-3,Melpar, Inc., Arlington, Virginia. (Paper presented atConference on Fire and Forest Meteorolgy of the AmericanMeteorological Society and the Society of American Foresters,March 1968.)
17. Hsi, G. and J. H. Nath, "A Laboratory Study on the Drag ForceDistribution Within Model Forest Canopies in Turbulent ShearFlow, " Fluid Dynamics and Diffusion Laboratory Report No.CER67-88GH-JHN-50. Colorado State University. 1968.
18. Kawatani, Takeshi, and R. N. Meroney, "Structure Of CanopyFluid Flow, " Fluid Dynamics and Diffusion Laboratory ]ReportCER67-68TK-RNM-33. Colorado State University. 1968.
19. Jensen. M. and N. Frank. "Model-Scale Test in Turbulent Wind.Part I, " The Danish Technical Press, Copenhagen, 1963.
20. Malhotra, R. C. and J. E. Cermak. 'Mass Diffusion in Neutraland Unstably Stratified Boundary-layer Flows." InternationalJournal of Heat and Mass Transfer. Vol. 7. pp. 169-186. 1964.
23
21. Denmead, 0. T. "Evaporation Sources and Apparent Diffusivitiesin a Forest Canopy, " Applied Meteorology, Vol. 3, pp. 383-389, 1964.
22. Wright, J. L. and E. R. Lemon, "Estimation of TurbulentExchange within a Corn Crop Canopy at Ellis Hollow (Ithaca,N. Y.), 1961," Internal Report 62-7, N. Y. State College ofAgriculture, Cornell University, July 1962.
Fig. 16. Lateral dispersion of a continuous point source ina model peg canopy (2. 54 x 2. 54 cm). xs 6 m,z = h
s
J 40
E
0
CD in
0
c( U
u 0r
00
Oe.1 114o oI9 N -W
1 -.
21000N -U0
lel'-4
41
G -T6
300 2"0
4"6"1
A i'
200
100
051015 2025 30
Fig.18.Lateral dispersion of a continuous point source ina model peg canopy (2. 54 x 2. 54 cm). x s=6 m,z ~h
SPEGS: #0.486~m, h =9cm, L 10,8m, 12, SPACED 2.54x 2,54cm
ZS =h 0,3m FROM SOURCE
Vw 12 rn/sec
1 42
8 0
-4
0
o cd
6I 0
ow
0.
LO'-
C9
0)
N0
43
T
EE E E E 0
@400 ' ~0S.'
L -0ie 2
02
co 0
0 0
010
EU .EIvN >
6cU 44
j 44
4~F 0 C
N~ .)
T -
0
0
oD r r,0) 0
E7 00
EU E
-4
45
0d
0
C'CU
N i N
x
Cd
0
0 m
o i
o coCd
0 04 * )
00
4 0C D N a D 05IDq N 0
d 46
ti
0
Cd
0.
0E
(U
E 0E 0.E0
CY C0
0
04
*X
0.
0400 0 ~Lc
I 1 1 E
00
47
0.
00
4. - N
r4a
4 0
0
CO
0.
0Y 0oa~0 0
in C
OoC
49
0.
0
00
0
on.' 0~ vEEE
£000
.00
-8-
9-01
>zo
0000
N' o.,
0 i" 0 Cd .0 C.00
o O"1 * @4
0 Ia
-4
E 0 If
co 4aoIf 0 z
u ui 0
C5 4-0
E C:
w CL " 4AIf ) uoNN
o.
0 0
C)
In
41 o)
9.01 X 0
E
U)-f
x N)
Q)
0
0
Sd0S4
41-
I-I
0
CL 0
cj N
<
N QN
U) U0N
10
In.
o 0
0
W Cdz0
w 0
OL-
0 0-0co
Joo
-~ N N
N1
E x
cn 0
00
0 -
00
0
4
I N %
-A0N E N N N N N V C) ~N
-ICY
0 0
('300
.2
"0
060
Zto0 L4J
11 0
x 21%
0 3 I
cli coOD C ~ OD WCs. CN N -- -
55
ci
(d
000
0~C4
-4
WC.'
-IY x
00 i
-I IN
C-ICUNOD I- E L
0tv
CLC
U
41
0h
II
NN
EE
E E E *.K q
000
00
n.
W~~A N O $ N .
N 0~~~u 0
12
0
N (A
UT,
0 0 00
In E
0 u0
it,
0 tv
10
0E
I ) cn
I I U-I--I--I----to
~~~1~ 0
0 E
o fl E
_ E
0.4 0t w a.
LA 0EEr
<a.N(
61
E
CY(1 (MJ
010
c~ EOC) *0 X 4
10 ~~ ~ w k E
~C)
N N12
C\)c
0 O
tn"-4
62
z(CM)26
24 Z =Icm
221 x = 0.2 5m
20 Pegs- 4S =0.48cm, h =9cm
18 Spaced: 2.54 x2.54 cm Diagonally
16
124
10
0 2 4 6 8 10 12 14 16 18 20 22 24 26y (cm)
Fig. 39. Gaseous plume cross-section of a continuous point sourcein a model peg canopy (2. 54 x 2. 54 cm diagonal). x s=6 m,z s =1 cm, x =0. 25 m
63
z
30 x =6 m
28 -c
26- Pegs: (P =0.48 CM, h 9 cm
24 -Spaced: 3.60 x360 cm(Diagonally)
22
20i/8
16
12
8
6
4
2
0 -o 2 4 6 8 10 12 14 16 18 20 22 24 26y (cm)
Fig. 40. Gaseous plume cross-section of a continuous pointsource in a model peg canopy (2. 54 x 2. 54 cmdiagonal). 'x s ~6m, zs =h, x =0. 5m
64
3.75Pegs*~0.48cm, hz9cm
Spaced& 5.08 x 5.08 cm
E0 900 I8 C 2
0 800 10 8 =2
0 1.25 2.50 3.75 5.00Y (cm)
Fig. 41. Gaseous plume cross-section of a continuous pointsource in a model peg canopy (5. 08 x 5. 08 cm).xs =0 m, z s= I1cm, x=O0.3 m
65
____ ___ _ _ ___ ___ __ ___ ___ IA) a)I . E0
004
Q) AZ
U 0~0 000
(rD
4
-4 0
0 7)L
-4 C
,Ik,
66
KJ x$_ O z_ lc \oS0
0
0
-3.70 x5 :0 ,zszIcm0 0 , 4.5cm Spacing -- -- __--
A 6m, Icm 2.54x2.54
a 6m, 4.5cm Diagonal
A 6m, 9cm m-- -2.5
0 6m, Icm Spacing2.54x2.54
01 110 0x (meters)
Fig. 43. 'variation of ground level concentration withdownstream distance
Pegs 0.48cm, h'9cm
67
00
0Q00
co
00
4J
00
- 4
B co
E E0~.o U
* * 02
coto :>
C~i C)%-
l.
0Nv
(W)409iH OWfl~d O!Isl!JB:DJD4:3
68
28-
24-
- 00
20-
- 00
a0
160 0
0 0
12- a 0
a 0
S a /0 xs,6m zs--Icm
0 0 A }XO.'5m 254x2.54 cma xi %6m
8- o x0l0m DIOQonlI %Or x} zI cm
a 0 A x,.6m 2.54x2.54cmD A O
• 4- o0oo
0 0.2 0.4 0.6 0.8 10K€ (m2/Ac)
Fig. 45. Coefficient of turbulent diffusion
69
0
w 0\
a U 0E0
enOe
Ch
F.- E 0
0 0
00in7N AC
70
E
, E
E E E E. 3
_. Ow§
0 1 1 ; 11 I
VC x x 41
h~N5E
o 00
E E.
Ow-
*4en
UnclassifiedSecivrity Classification
DOCUMENT CONTROL DATA - R&D(Security class iItcoition of lI to. bidy of abatrac I and indexing annsiouoion mu at be entered when the ove rat l report aca o i
2275C, 36. OTpHER wREPORT No(S) (Anv other numbers Ael ay I-oesno
ohs$ report)
* d
010 A VAIL ABILITY'ILIUITATiON NOTICES
Distribution of this report is unlimited
I I SUPPL EMCNTARY NOTES 123 SPONSORINkG MILITARY ACTIVITY
U. S. Army Materiel Command
13 ABTRACTA point source of an air-helium mixture was releasedcontinuously at various positions within a simulated canopy composed of9 cm high pegs. 0. 48 cm diameter, spaced in several arrays (2. 54 x 2. 54,3. 55 x 3. 55, and 5.08 x 5.08 cm). Variations of the vertical location of thesoarce revealed the strongly nonisotropic character of diffusion within acanopy with respect to the relative diffusioai rates in the lateral and verticaldirections. When the source was placed at various downstream distancesfrom the edge of the canopy, it displayed a tendency to exhale the plume nearthe frunt of the model canopy and to inhale the plume at distances furtherdownstream. Calculations of the turbulent diffusion coefficient, K to withinand above the canopy from the experimental data. reveal both a constantregion and a region of linear increase with height mnrase as suggested byprevious authors.
1. ORIGINATING ACTIVITY: Enter the name and address 10. AVAILADILITY/LIMITATION NOTICES: Enter any lint-of the ccntractor, subcontractor, grantee, Department of De- ftat ions on further dissemination of the report. other than thosefense actlvit7 or other organization (corporate author) issuing i y classification usi"g standard statementsthe report. such as:
2a. REPORT SECUIRTY CLASSIFICATION: Enter the over- (1) "0uilied requesters may obtain copies of thisall security classification of the reporl. Indicate whether report from DDC.""Restricted Data" is included. Marking is to be in accord-ance with appropriate security regulations. (2) "Foreign announcement and dissemination of this
2b. GROUP: Automatic downgrading is specified in DOD Di- repor by DC is not authorized."rective 5200. 10 and Armed Forces Industrial Manual. Enter (3) "U. S. Gcvernment agencies may obtain copies ofthe group number. Also. when applicable, show that optional this report directly from DDC. Other qualified DDCmarkings have been used for Group 3 and Group 4 as author- users shall request throughized.
3. REPORT TITLE: Enter the complete report title in all (4) "J. S. niitary agencies may obtain copies of thiscapital letters. Titles in all cases should be unclassified. report directly from DDC. Other quaified usersIf a meaningful title cannot be selected without classifica- shall request throughtion, show title classification in all capitals in parenthesis ,immediately following the title. .__
4. DESCRIPTIVE NOTES. If appropriate, enter the type of (5) "All distribution of this report is controlled. Qual-report, e.g., interim, progress, summary, annual, or final. ified DDC i:3ers shall request throughGive the inclusive dates when a specific reporting period is ,"covered.
If the report has been furnished to the Office of Technical5. AUTHOR(S): Enter the name(s) of autho(s) as shown on Services. Department of Commerce, for sale to the public, indi-or in the report. Enter last nare, first name, middle initial. cate this fact and enter the price, if known.If military, show rank and branch of service. The name of Ithe principal author is an absolute minimum requirement. 11. SUPPLEMENTARY NOTES: Use for additional explana-
6. REPORT DATE: Enter the date of the report as day, tory notes.
month, year; or month, year, If more than one date appears 12. SPONSORING MILITARY ACTIVITY: Enter the name ofon the report, -,se date of publication, the departmental project office or laboratory sponsoring (pay-
7.. TOTAL NUMBER OF PAGES: The total page count ing for) the research and development. Include address.
should follow normal paginaiion procedures, i.e., enter the 13. ABSTRACT: Enter an abstract giving a brief and factualnumber of pages containing information. summary of the document indicative of the report, even though
it may alsi(- appear elsewhere in the body of the technical re-7b. NUMBER OF REFERENCES: Enter he total number of port. If additional space is required, a continuation sheetreferences cited in the report. shall be attached.
go. CONTRACT OR GRANT NUMBER: If appropriate, enter It is highly desirable that the abstract of classified re-the applicable number of the contract or grant under which ports he unclassifi,,d. Eac-h paragraph of the abstract shallthe report was written. end with an indication of the military security classification
8b. 8c, & 8d. PROJECT NUMBER: Enter the appropriate of the information in the paragraph, represented as (TS), (S).
military department identification, such as project number, (C), o (U).
subproject -:umber, ". ,item numbers, task number, etc. There is no limitation on the length of the abstract. How-
9a. ORIGINATOR'b REPORT NUMBER(S): Enter the offi- ever, the suggested length is from 150 to 225 words.
cial report number by which the document will be identifiod 14. KEY WORDS: Key words are technically meaningful termsand controlled by the originating activity. This number must or short phrases that characterize a report and may be used asbe unique to this report, index entries for cataloging the report. Key words must be
qb. OTHER REPORT NUMBER(S): If the report has been selected so that no security classification is required. Iden-
assigned any other report numbers (either ki the originator fiers, such as equipment model designation, trade name, itili-
or by the sponsor), also enter this number(s), tarv project code name, geographic location, may be used askey wnrds hut will he followed bV an indication of t. hnicalcontext. The assignment of links, rules, and weights isoptional.