{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,25]],"date-time":"2026-08-25T02:31:13Z","timestamp":1787625073857,"version":"build-2736575974"},"reference-count":49,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2016,5,12]],"date-time":"2016-05-12T00:00:00Z","timestamp":1463011200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The present work studies the effect of three insect-proof screens with different geometrical and aerodynamic characteristics on the air velocity and temperature inside a Mediterranean multi-span greenhouse with three roof vents and without crops, divided into two independent sectors. First, the insect-proof screens were characterised geometrically by analysing digital images and testing in a low velocity wind tunnel. The wind tunnel tests gave screen discharge coefficient values of Cd,\u03c6 of 0.207 for screen 1 (10 \u00d7 20 threads\u00b7cm\u22122; porosity \u03c6 = 35.0%), 0.151 for screen 2 (13 \u00d7 30 threads\u00b7cm\u22122; \u03c6 = 26.3%) and 0.325 for screen 3 (10 \u00d7 20 threads\u00b7cm\u22122; porosity \u03c6 = 36.0%), at an air velocity of 0.25 m\u00b7s\u22121. Secondly, when screens were installed in the greenhouse, we observed a statistical proportionality between the discharge coefficient at the openings and the air velocity ui measured in the centre of the greenhouse, ui = 0.856 Cd + 0.062 (R2 = 0.68 and p-value = 0.012). The inside-outside temperature difference \u0394Tio diminishes when the inside velocity increases following the statistically significant relationship \u0394Tio = (\u2212135.85 + 57.88\/ui)0.5 (R2 = 0.85 and p-value = 0.0011). Different thread diameters and tension affects the screen thickness, and means that similar porosities may well be associated with very different aerodynamic characteristics. Screens must be characterised by a theoretical function Cd,\u03c6 = [(2e\u03bc\/Kp\u03c1)\u00b7(1\/us) + (2eY\/Kp0.5)]\u22120.5 that relates the discharge coefficient of the screen Cd,\u03c6 with the air velocity us. This relationship depends on the three parameters that define the aerodynamic behaviour of porous medium: permeability Kp, inertial factor Y and screen thickness e (and on air temperature that determine its density \u03c1 and viscosity \u03bc). However, for a determined temperature of air, the pressure drop-velocity relationship can be characterised only with two parameters: \u0394P = aus2 + bus.<\/jats:p>","DOI":"10.3390\/s16050690","type":"journal-article","created":{"date-parts":[[2016,5,12]],"date-time":"2016-05-12T10:18:45Z","timestamp":1463048325000},"page":"690","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":21,"title":["Wind Tunnel Analysis of the Airflow through Insect-Proof Screens and Comparison of Their Effect When Installed in a Mediterranean Greenhouse"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5908-7580","authenticated-orcid":false,"given":"Alejandro","family":"L\u00f3pez","sequence":"first","affiliation":[{"name":"Research Centre CIAIMBITAL, University of Almer\u00eda, Ctra. Sacramento s\/n, Almer\u00eda 04120, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0492-4978","authenticated-orcid":false,"given":"Francisco","family":"Molina-Aiz","sequence":"additional","affiliation":[{"name":"Research Centre CIAIMBITAL, University of Almer\u00eda, Ctra. Sacramento s\/n, Almer\u00eda 04120, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2866-471X","authenticated-orcid":false,"given":"Diego","family":"Valera","sequence":"additional","affiliation":[{"name":"Research Centre CIAIMBITAL, University of Almer\u00eda, Ctra. Sacramento s\/n, Almer\u00eda 04120, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Araceli","family":"Pe\u00f1a","sequence":"additional","affiliation":[{"name":"Research Centre CIAIMBITAL, University of Almer\u00eda, Ctra. Sacramento s\/n, Almer\u00eda 04120, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2016,5,12]]},"reference":[{"key":"ref_1","unstructured":"Valera, D.L., Belmonte, L.J., Molina-Aiz, F.D., and L\u00f3pez, A. (2016). Greenhouse Agriculture in Almer\u00eda. A Comprehensive Techno-Economic Analysis, Cajamar Caja Rural. [1st ed.]. Available online: http:\/\/www.publicacionescajamar.es\/series-tematicas\/economia\/greenhouse-agriculture-in-almeria-a-comprehensive-techno-economic-analysis\/."},{"key":"ref_2","unstructured":"Baudoin, W., Nono-Womdim, R., Lutaladio, N., Hodder, A., Castilla, N., Leonardi, C., De Pascale, S., Qaryouti, M., and Duffy, R. (2013). Good Agricultural Practices for Greenhouse Vegetable Crops. Principles for Mediterranean Climate Areas, Food and Agriculture Organization of the United Nations (FAO). [1st ed.]."},{"key":"ref_3","unstructured":"Molina-Aiz, F.D. (2010). Simulaci\u00f3n y modelaci\u00f3n de la ventilaci\u00f3n en invernaderos de Almer\u00eda mediante la utilizaci\u00f3n de Din\u00e1mica Computacional de Fluidos (Ventilation simulation and modelling by computational fluid dynamics (CFD) in Almer\u00eda-type greenhouses). [Ph.D. Thesis, University of Almer\u00eda]. (In Spanish)."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"338","DOI":"10.5424\/sjar\/2014122-4956","article-title":"Microclimate evaluation of a new design of insect-proof screens in a Mediterranean greenhouse","volume":"12","author":"Valera","year":"2014","journal-title":"Span. J. Agric. Res."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"183","DOI":"10.17660\/ActaHortic.1990.281.21","article-title":"Comparison of different systems for static ventilation of hemispheric plastic greenhouses","volume":"281","author":"Verheye","year":"1990","journal-title":"Acta Hortic."},{"key":"ref_6","unstructured":"Castilla, N.P. (2007). Invernaderos de Pl\u00e1stico. Tecnolog\u00eda y Manejo (Plastic Greenhouses. Technology and Management), Mundi-Prensa. [2nd ed.]."},{"key":"ref_7","unstructured":"Junta de Andaluc\u00eda, Reglamento Espec\u00edfico de Producci\u00f3n Integrada de Cultivos Hort\u00edcolas Protegidos (Specific Regulation on Integrated Protected Horticultural Crop Production). Available online: http:\/\/www.juntadeandalucia.es\/boja\/2007\/211\/2."},{"key":"ref_8","first-page":"6","article-title":"L\u2019efficacit\u00e9 \u00e9nerg\u00e9tique dans la conception des serres m\u00e9diterran\u00e9ennes (Energy efficiency in the design of Mediterranean greenhouses)","volume":"96","year":"1992","journal-title":"Plasticulture"},{"key":"ref_9","unstructured":"\u00c1lvarez, A.J. (2010). Estudio de las Caracter\u00edsticas Geom\u00e9tricas y del Comportamiento Aerodin\u00e1mico de las Mallas Antiinsectos Utilizadas en los Invernaderos como Medida de Protecci\u00f3n Vegetal (Analysis of the Geometric Characteristics and Aerodynamic Behaviour of Insect-Proof Screens Used in Greenhouses to Protect Crops). [Ph.D. Thesis, University of Almer\u00eda]. (In Spanish)."},{"key":"ref_10","first-page":"1","article-title":"Screening as part of insect and disease management in the greenhouse","volume":"34","author":"Baker","year":"1989","journal-title":"N.C. Flower Grow. Bull."},{"key":"ref_11","first-page":"13","article-title":"The effect of types of greenhouse screens on the presence of western flower thrips: A preliminary study","volume":"16","author":"Berlinger","year":"1993","journal-title":"IOBC\/WPRS Bull."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"159","DOI":"10.1016\/j.agrformet.2007.01.005","article-title":"The effect of screened openings on greenhouse microclimate","volume":"143","author":"Teitel","year":"2007","journal-title":"Agric. For. Meteorol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1016\/S0168-1923(03)00071-6","article-title":"Simulation of climatic conditions in full-scale greenhouse fitted with insect-proof screens","volume":"118","author":"Fatnassi","year":"2003","journal-title":"Agric. For. Meteorol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"2151","DOI":"10.13031\/2013.25396","article-title":"The impact of insect screens and ventilation openings on the greenhouse microclimate","volume":"51","author":"Kittas","year":"2008","journal-title":"Trans. ASABE"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"224","DOI":"10.1016\/j.biosystemseng.2009.06.013","article-title":"A study of natural ventilation in an Almer\u00eda-type greenhouse with insect screens by means of tri-sonic anemometry","volume":"104","author":"Valera","year":"2009","journal-title":"Biosyst. Eng."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1016\/S0168-1923(01)00280-5","article-title":"The effect of insect-proof screens in roof openings on greenhouse microclimate","volume":"110","author":"Teitel","year":"2001","journal-title":"Agric. For. Meteorol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"301","DOI":"10.1016\/j.biosystemseng.2005.11.014","article-title":"Optimisation of greenhouse insect screening with computational fluid dynamics","volume":"93","author":"Fatnassi","year":"2006","journal-title":"Biosyst. Eng."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1016\/j.biosystemseng.2006.02.016","article-title":"Microclimate and air exchange rates in greenhouses covered with different nets in the humid tropics","volume":"94","author":"Tantau","year":"2006","journal-title":"Biosyst. Eng."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"86","DOI":"10.1016\/j.biosystemseng.2009.04.008","article-title":"Analysis of the role of sidewall vents on buoyancy-driven natural ventilation in parral-type greenhouses with and without insect screens using computational fluid dynamics","volume":"104","author":"Baeza","year":"2009","journal-title":"Biosyst. Eng."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"207","DOI":"10.1016\/S0168-1699(01)00188-0","article-title":"Numerical simulation of the airflow and temperature distribution in a tunnel greenhouse equipped with insect-proof screen in the openings","volume":"34","author":"Bartzanas","year":"2002","journal-title":"Comput. Electron. Agric."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"427","DOI":"10.1016\/j.biosystemseng.2005.01.001","article-title":"Effect of vent openings and insect screens on greenhouse ventilation","volume":"93","author":"Katsoulas","year":"2006","journal-title":"Biosyst. Eng."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"171","DOI":"10.1006\/jaer.1998.0404","article-title":"Effect of insect-proof screens and roof openings on greenhouse ventilation","volume":"73","author":"Montero","year":"1999","journal-title":"J. Agric. Eng. Res."},{"key":"ref_23","first-page":"89","article-title":"Natural ventilation of parral greenhouses","volume":"87","author":"Baeza","year":"2004","journal-title":"Biosyst. Eng."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1016\/S1537-5110(02)00221-0","article-title":"Determination of greenhouse specific aspects of ventilation using three dimensional computational fluid dynamics","volume":"84","author":"Campen","year":"2003","journal-title":"Biosyst. Eng."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"419","DOI":"10.17660\/ActaHortic.2005.691.50","article-title":"Greenhouse design applying CFD for Indonesian conditions","volume":"691","author":"Campen","year":"2005","journal-title":"Acta Hortic."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"129","DOI":"10.17660\/ActaHortic.1989.248.13","article-title":"A support system for natural ventilation design of greenhouses based on computational aerodynamics","volume":"284","author":"Okushima","year":"1989","journal-title":"Acta Hortic."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1006\/jaer.1999.0442","article-title":"Characterization and modelling of the air fluxes induced by natural ventilation in a greenhouse","volume":"74","author":"Boulard","year":"1999","journal-title":"J. Agric. Eng. Res."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"172","DOI":"10.1016\/j.biosystemseng.2009.10.005","article-title":"Using computational fluid dynamics simulations to determine pressure drops on woven screens","volume":"105","author":"Teitel","year":"2010","journal-title":"Biosyst. Eng."},{"key":"ref_29","unstructured":"Bot, G.P.A. (1983). Greenhouse Climate: From Physical Processes to a Dynamic Model. [Ph.D. Thesis, Wageningen Agricultural University]."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"95","DOI":"10.1016\/0168-1923(95)02232-M","article-title":"Quantifcation du taux d\u2019a\u00e9ration d\u2019une serre \u00e0 ouvrant continu en toiture (Quantification of the ventilation rate of a greenhouse with a continuous roof opening)","volume":"77","author":"Kittas","year":"1995","journal-title":"Agric. For. Meteorol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"415","DOI":"10.13031\/2013.21268","article-title":"Natural ventilation of a greenhouse with ridge and side openings: Sensitivity to temperature and wind effects","volume":"40","author":"Kittas","year":"1997","journal-title":"Trans. ASAE"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"219","DOI":"10.1006\/jaer.1996.0023","article-title":"Measurement and analysis of air exchange rates in a greenhouse with continuous roof and side openings","volume":"63","author":"Papadakis","year":"1996","journal-title":"J. Agric. Eng. Res."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1083","DOI":"10.13031\/2013.9940","article-title":"Influence of an insect screen on greenhouse ventilation","volume":"45","author":"Kittas","year":"2002","journal-title":"Trans. ASAE"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1006\/bioe.2001.0056","article-title":"SE\u2014Structures and Environment: Ventilation Performance of a Large Canarian-Type Greenhouse Equipped with Insect-Proof Nets","volume":"82","author":"Fatnassi","year":"2002","journal-title":"Biosyst. Eng."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"216","DOI":"10.1016\/j.biosystemseng.2009.04.018","article-title":"Influence of sampling positions on accuracy of tracer gas measurements in ventilated spaces","volume":"104","author":"Vranken","year":"2009","journal-title":"Biosyst. Eng."},{"key":"ref_36","unstructured":"Valera, D.L., \u00c1lvarez, A.J., Molina, F.D., Pe\u00f1a, A., L\u00f3pez, J.A., and Madue\u00f1o, A. (2003, January 16\u201324). Caracterizaci\u00f3n geom\u00e9trica de diferentes tipos de agrotextiles utilizados en invernaderos. Proceedings of the II Congreso Nacional de Agroingenier\u00eda, C\u00f3rdoba, Spain. (In Spanish)."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"134","DOI":"10.1016\/j.compag.2012.01.001","article-title":"Software for the geometric characterisation of insect-proof screens","volume":"82","author":"Oliva","year":"2012","journal-title":"Comput. Electron. Agric."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"958","DOI":"10.5424\/sjar\/2013114-4093","article-title":"Field analysis of the deterioration after some years of use of four insect-proof screens utilized in Mediterranean greenhouses","volume":"11","author":"Valera","year":"2013","journal-title":"Span. J. Agric. Res."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"273","DOI":"10.5424\/sjar\/2006044-204","article-title":"Aerodynamic analysis of several insect-proof screens used in greenhouses","volume":"4","author":"Valera","year":"2006","journal-title":"Span. J. Agric. Res."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"447","DOI":"10.1016\/j.biosystemseng.2006.01.016","article-title":"A wind tunnel study of airflow through horticultural crops: Determination of the drag coefficient","volume":"93","author":"Valera","year":"2006","journal-title":"Biosyst. Eng."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"19723","DOI":"10.3390\/s150819723","article-title":"An Auto-Tuning PI Control System for an Open-Circuit Low-Speed Wind Tunnel Designed for Greenhouse Technology","volume":"15","author":"Espinoza","year":"2015","journal-title":"Sensors"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"105","DOI":"10.1006\/jaer.1997.0157","article-title":"Analysis of the airflow characteristics of greenhouse screening materials","volume":"67","author":"Miguel","year":"1997","journal-title":"J. Agric. Eng. Res."},{"key":"ref_43","first-page":"169","article-title":"Screen hole size and barriers for exclusion on insect pest of glasshouse crops","volume":"26","author":"Bethke","year":"1991","journal-title":"J. Entomol. Sci."},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Nield, D.A., and Bejan, A. (1998). Convection in Porous Media, Springer. [1st ed.].","DOI":"10.1007\/978-1-4757-3033-3"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"327","DOI":"10.17660\/ActaHortic.2000.534.38","article-title":"Buoyancy-driven ventilation in a greenhouse cooled by a fogging system","volume":"534","author":"Arbel","year":"2000","journal-title":"Acta Hortic."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"217","DOI":"10.1016\/S1537-5110(03)00115-6","article-title":"Airflow resistance of greenhouse ventilators with and without insect screens","volume":"86","author":"Bailey","year":"2003","journal-title":"Biosyst. Eng."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"4817","DOI":"10.1016\/j.ces.2007.06.001","article-title":"On the pressure drop modeling of monofilament-woven fabrics","volume":"62","author":"Wang","year":"2007","journal-title":"Chem. Eng. Sci."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"249","DOI":"10.1006\/jaer.1997.0167","article-title":"Natural ventilation performance of six greenhouse and tunnel types","volume":"67","author":"Boulard","year":"1997","journal-title":"J. Agric. Eng. Res."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1016\/S0168-1923(99)00082-9","article-title":"Greenhouse crop transpiration simulation from external climate conditions","volume":"100","author":"Boulard","year":"2000","journal-title":"Agric. For. Meteorol."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/16\/5\/690\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T19:23:47Z","timestamp":1760210627000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/16\/5\/690"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2016,5,12]]},"references-count":49,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2016,5]]}},"alternative-id":["s16050690"],"URL":"https:\/\/doi.org\/10.3390\/s16050690","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2016,5,12]]}}}