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פותח על ידי קלירמאש פתרונות בע"מ -
Effect of crop on the wind and shear-stress profiles inside and above an 'infinite' screenhouse
Year:
2017
Source of publication :
Acta Horticulturae
Authors :
מכמנדרוב, יונתן
;
.
Volume :
1154
Co-Authors:
Seginer, I., Technion, Haifa, Israel
Pirkner, M., ARO, Bet Dagan, Israel
Achiman, O., ARO, Bet Dagan, Israel
Mekhmandarov, Y., ARO, Bet Dagan, Israel
Tanny, J., ARO, Bet Dagan, Israel
Facilitators :
From page:
105
To page:
110
(
Total pages:
6
)
Abstract:
The mixing-length model, traditionally used to model wind profiles above extended open fields, has been modified to include a horizontal screen (roof) above the crop. According to this model, two attributes (parameters) define the aerodynamic properties of the screen: a characteristic resistance (drag) and a characteristic mixing-length. The former affects the horizontal force on the structure and the latter affects the vertical turbulent transfer across the roof. Similar parameters (drag and mixing-length) also define the aerodynamic properties of the crop. In our previous reports described the mixing-length model, we calculated velocity and shear profiles and estimated the screen aerodynamic parameters. Here, we also estimate the aerodynamic properties of the crop canopy. Data from two large screenhouses, one covered with a fine 'insect' screen and another with a coarse 'shading' screen, were used in the analysis. It turns out that in both cases the crop mixing-length does not limit the size of the turbulent eddies and, therefore, does not affect the turbulent transfer. Crop drag, however, has some effect. All things considered, estimating the aerodynamic properties of fine screens from wind and shear profiles does not require detailed and accurate crop information.
Note:
Related Files :
Crop properties
Drag force
Large screenhouses
Mixing-length
Momentum-flux
One-dimensional profiles
Screen properties
עוד תגיות
תוכן קשור
More details
DOI :
10.17660/ActaHortic.2017.1154.14
Article number:
Affiliations:
Database:
סקופוס
Publication Type:
מאמר מתוך כינוס
;
.
Language:
אנגלית
Editors' remarks:
ID:
23412
Last updated date:
02/03/2022 17:27
Creation date:
16/04/2018 23:59
Scientific Publication
Effect of crop on the wind and shear-stress profiles inside and above an 'infinite' screenhouse
1154
Seginer, I., Technion, Haifa, Israel
Pirkner, M., ARO, Bet Dagan, Israel
Achiman, O., ARO, Bet Dagan, Israel
Mekhmandarov, Y., ARO, Bet Dagan, Israel
Tanny, J., ARO, Bet Dagan, Israel
Effect of crop on the wind and shear-stress profiles inside and above an 'infinite' screenhouse
The mixing-length model, traditionally used to model wind profiles above extended open fields, has been modified to include a horizontal screen (roof) above the crop. According to this model, two attributes (parameters) define the aerodynamic properties of the screen: a characteristic resistance (drag) and a characteristic mixing-length. The former affects the horizontal force on the structure and the latter affects the vertical turbulent transfer across the roof. Similar parameters (drag and mixing-length) also define the aerodynamic properties of the crop. In our previous reports described the mixing-length model, we calculated velocity and shear profiles and estimated the screen aerodynamic parameters. Here, we also estimate the aerodynamic properties of the crop canopy. Data from two large screenhouses, one covered with a fine 'insect' screen and another with a coarse 'shading' screen, were used in the analysis. It turns out that in both cases the crop mixing-length does not limit the size of the turbulent eddies and, therefore, does not affect the turbulent transfer. Crop drag, however, has some effect. All things considered, estimating the aerodynamic properties of fine screens from wind and shear profiles does not require detailed and accurate crop information.
Scientific Publication
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