Abstract
A vapour of radio-lead (212Pb) has been used to measure the Sherwood number, Sh, of model leaves at various angles of incidence,Φ, to the airstream in a wind tunnel. The results forΦ=0 are compared with Pohlhausen's formula and the results forΦ ⊋ 0, with Powell's experiments. The local values of Sh on the upwind and downwind sides of discs have been obtained. For leaves in the canopy, Sh was found to be about 25% greater than would be predicted by applying Pohlhausen's equation without correction for orientation.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Abbreviations
- a :
-
area of one side of disc or leaf cm2
- C D :
-
drag coefficient
- d :
-
diameter of cylinder or circular disc cm
- d :
-
equivalent diameter of leaf(4a/π) 1/2 cm
- d 0 :
-
zero plane displacement cm
- D :
-
molecular diffusivity cm2 s−1
- F :
-
flux of vapour per unit area of surface units cm−2 s−1
- h :
-
height of crop cm
- l :
-
length of flat plate cm
- Re:
-
Reynolds number=udv −1
- r :
-
resistance=(χ 1−χ0)/F cm−1 s
- r D :
-
bulk resistance cm−1 s
- Sc:
-
Schmidt number=v/D
- Sh:
-
Sherwood number=r −1 lD −1 orr −1 dD −1
- u :
-
wind speed cm s−1
- u * :
-
friction velocity cm s−1
- v g :
-
velocity of deposition=F/(χ1−χ0)=r −1 cm s−1
- x :
-
distance from leading edge of plate cm
- z :
-
height above soil cm
- z 0 :
-
roughness length cm
- α :
-
shape factor
- Φ :
-
angle between plane and wind direction deg
- v :
-
kinematic viscosity cm2 s−1
- ϱ :
-
density of air g cm−3
- χ :
-
vapour density units cm3
- χ 1 :
-
vapour density, in free air units cm3
- χ 0 :
-
vapour density, at surface units cm3
References
Chamberlain, A. C.: 1966, ‘Transport of gases to and from Grass and Grass-Like Surfaces’,Proc. Roy. Soc. A. 290, 235–260.
Chamberlain, A. C.: 1968, ‘Transport of Gases to and from Surfaces with Bluff and Wave-Like Roughness Elements’,Quart. J. Roy. Meteorol. Soc. 94, 318–322.
Chamberlain, A. C. and Dyson, E. D.: 1956, ‘The Dose to the Trachea and Bronchi from the Decay Products of Radon and Thoron’,Brit. J. Radiol. XXIX, 317–325.
Goldstein, S. (ed.): 1938.Modern Development in Fluid Dynamics, Clarendon, Oxford.
Parkhurst, D. F., Duncan, P. R., Gates, D. M., and Kreith, F.: 1968, ‘Wind Tunnel Modelling of Convection of Heat Between Air and Broad Leaves of Plants’,Agr. Meteorol. 5, 3347.
Pearman, G. I., Weaver, H. L., and Tanner, C. B.: 1972, ‘Boundary Layer Heat Transfer Coefficients Under Field Conditions’,Agric. Meteorol. 10, 83–92.
Powell, R. W.: 1940, ‘Further Experiments on the Evaporation of Water from Saturated Surfaces’,Trans. Inst. Chem. Engrs. 18, 36–55.
Richardson, P. D.: 1967, ‘Effects of Sound and Vibration on Heat Transfer’,Appl. Mech. Rev. 20, 201–217.
Schuepp, P. H.: 1972, ‘Studies of Forced-Convection Heat and Mass Transfer of Fluttering Realistic Leaf Models’,Boundary-Layer Meteorol. 2, 263–274.
Thom, A. S.: 1968, ‘The Exchange of Momentum Mass and Heat Between an Artificial Leaf and the Airflow in a Wind Tunnel’,Quart. J. Roy. Meteorol. Soc. 94, 44–55.
Thom, A. S.: 1972, ‘Momentum, Mass and Heat Exchange of Vegetation’,Quart. J. Roy. Meteorol. Soc. 98, 124–134.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Chamberlain, A.C. Mass transfer to bean leaves. Boundary-Layer Meteorol 6, 477–486 (1974). https://doi.org/10.1007/BF02137680
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02137680