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Airflow characteristics and patterns in screenhouses covered with fine-mesh screens with either roof or roof and side ventilation
Year:
2015
Source of publication :
Biosystems Engineering
Authors :
Antler, Aharon
;
.
Garcia-Teruel, Monica
;
.
Ibanez, Pablo F.
;
.
Laufer, Sagi
;
.
Levi, Aharon
;
.
Tanny, Josef
;
.
Teitel, Meir
;
.
Volume :
131
Co-Authors:
Teitel, M., Institute of Agricultural Engineering, Agricultural Research Organization, The Volcani Center, P.O.B. 6, Bet Dagan, Israel
Garcia-Teruel, M., Institute of Agricultural Engineering, Agricultural Research Organization, The Volcani Center, P.O.B. 6, Bet Dagan, Israel
Ibanez, P.F., Institute of Agricultural Engineering, Agricultural Research Organization, The Volcani Center, P.O.B. 6, Bet Dagan, Israel
Tanny, J., Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization, The Volcani Center, P.O.B. 6, Bet Dagan, Israel
Laufer, S., Institute of Agricultural Engineering, Agricultural Research Organization, The Volcani Center, P.O.B. 6, Bet Dagan, Israel
Levi, A., Institute of Agricultural Engineering, Agricultural Research Organization, The Volcani Center, P.O.B. 6, Bet Dagan, Israel
Antler, A., Institute of Agricultural Engineering, Agricultural Research Organization, The Volcani Center, P.O.B. 6, Bet Dagan, Israel
Facilitators :
From page:
1
To page:
14
(
Total pages:
14
)
Abstract:
In many countries fine mesh screens are used to protect agricultural crops. The low porosity of such screens impedes the exchange of mass, heat and momentum between the air around the crop and that occur in the atmosphere, thereby modifying the crop microclimate. Experiments were carried out aimed at determining the internal airflow characteristics and patterns of screenhouses. The results showed that screenhouses reduced air velocity compared to that in an open field. For a given windspeed the air velocity inside the screenhouse increased with height. The internal air velocity increased with external windspeed but it increased to a greater extent near to the roof. Flow patterns and characteristics were affected by whether the screenhouse was ventilated only via the roof or via the roof and sidewalls. When the screenhouse was ventilated from the roof and side panels the air velocity was higher than under roof ventilation alone, and the airflow direction, both within the canopy and above it, was usually in a similar direction to that of the outside wind. However, under roof ventilation alone the internal airflow direction was generally opposite to that of the external wind, resulting in outflow through the windward section of the roof and inflow through the leeward section. In the central region of the screenhouse the mean vertical velocity within the canopy was near zero and its fluctuations with time were relatively small. Near the roof, there was a mean net inflow and the velocity fluctuations were much larger. © 2015 IAgrE.
Note:
Related Files :
Airflow characteristics
Crops
Insect proof screen
Internal airflow
Mean vertical velocity
Tomato plants
Velocity
Ventilation
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Related Content
More details
DOI :
10.1016/j.biosystemseng.2014.12.010
Article number:
0
Affiliations:
Database:
Scopus
Publication Type:
article
;
.
Language:
English
Editors' remarks:
ID:
27405
Last updated date:
02/03/2022 17:27
Creation date:
17/04/2018 00:30
Scientific Publication
Airflow characteristics and patterns in screenhouses covered with fine-mesh screens with either roof or roof and side ventilation
131
Teitel, M., Institute of Agricultural Engineering, Agricultural Research Organization, The Volcani Center, P.O.B. 6, Bet Dagan, Israel
Garcia-Teruel, M., Institute of Agricultural Engineering, Agricultural Research Organization, The Volcani Center, P.O.B. 6, Bet Dagan, Israel
Ibanez, P.F., Institute of Agricultural Engineering, Agricultural Research Organization, The Volcani Center, P.O.B. 6, Bet Dagan, Israel
Tanny, J., Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization, The Volcani Center, P.O.B. 6, Bet Dagan, Israel
Laufer, S., Institute of Agricultural Engineering, Agricultural Research Organization, The Volcani Center, P.O.B. 6, Bet Dagan, Israel
Levi, A., Institute of Agricultural Engineering, Agricultural Research Organization, The Volcani Center, P.O.B. 6, Bet Dagan, Israel
Antler, A., Institute of Agricultural Engineering, Agricultural Research Organization, The Volcani Center, P.O.B. 6, Bet Dagan, Israel
Airflow characteristics and patterns in screenhouses covered with fine-mesh screens with either roof or roof and side ventilation
In many countries fine mesh screens are used to protect agricultural crops. The low porosity of such screens impedes the exchange of mass, heat and momentum between the air around the crop and that occur in the atmosphere, thereby modifying the crop microclimate. Experiments were carried out aimed at determining the internal airflow characteristics and patterns of screenhouses. The results showed that screenhouses reduced air velocity compared to that in an open field. For a given windspeed the air velocity inside the screenhouse increased with height. The internal air velocity increased with external windspeed but it increased to a greater extent near to the roof. Flow patterns and characteristics were affected by whether the screenhouse was ventilated only via the roof or via the roof and sidewalls. When the screenhouse was ventilated from the roof and side panels the air velocity was higher than under roof ventilation alone, and the airflow direction, both within the canopy and above it, was usually in a similar direction to that of the outside wind. However, under roof ventilation alone the internal airflow direction was generally opposite to that of the external wind, resulting in outflow through the windward section of the roof and inflow through the leeward section. In the central region of the screenhouse the mean vertical velocity within the canopy was near zero and its fluctuations with time were relatively small. Near the roof, there was a mean net inflow and the velocity fluctuations were much larger. © 2015 IAgrE.
Scientific Publication
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