Evaluation of wind pressure acting on multi-span greenhouses using CFD technique, Part 2: Application of the CFD model

Kim, Rack-woo; Hong, Suk-Jin; Lee, In-Bok; Kwon, Kilsung

doi:10.1016/j.biosystemseng.2017.09.011

Cited by 40 publications

(24 citation statements)

References 26 publications

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“…The ANSYS-ICEM software was used to build a computational domain of suffi cient size to allow the develop-ment of airfl ow and an adequate defi nition of the atmospheric boundary layer. This computational domain, which included the greenhouse and its surrounding outdoor environment, had dimensions of: 225 m width (x-axis) and 70 m height (y-axis), was built following the recommendations given by Kim et al (2017). In the mesh generation process, an unstructured grid of square elements with a total of 1,021,713 elements is selected, this grid was selected after verifi cation of independence of the numerical solution of the grid size.…”

Section: Computational Domain and Boundary Conditionsmentioning

confidence: 99%

Study of natural ventilation in a Gothic multi-tunnel greenhouse designed to produce rose (Rosa spp.) in the high-Andean tropic

Villagrán

Bojacá

2019

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In tropical regions the production of ornamentals is developed exclusively in naturally ventilated plastic greenhouses, which sometimes leads to inappropriate microclimates with high temperatures and humidity that limit the productive development of plants. The aim of this work was to study air flows, temperature distribution and relative humidity inside an alternative greenhouse designed to produce rose (Rosa spp.). Three configurations of ventilation, side ventilation (SV), roof ventilation (RC) and combined roof and side ventilation (RSV) were analyzed. The methodological development was based on the use of a previously validated CFD-2D numerical simulation model, which showed an adequate fit between the measured and simulated data, obtaining MAE and RMSE values for temperature and relative humidity of 0.44 and 0.47 °C, 3.99% and 4.04% respectively. The results obtained for the predominant climatic conditions of the study region showed that the highest ventilation rates were obtained for RSV, with values of 0.044 and 0.182 m 3 m -2 s -1 , this ventilation efficiency propitiated the generation of a homogeneous microclimate, with temperature and relative humidity values adequate to produce rose (Rosa spp). ResumoEstudo da ventilação natural em uma estufa gótica multi-túnel projetada para produzir rosa (Rosa spp.) no trópico alto-andino. Nas regiões tropicais, a produção de plantas ornamentais é desenvolvida exclusivamente em estufas plásticas ventiladas de forma natural, o que significa que em algumas ocasiões microclimas inadequados são gerados com altas temperaturas e umidade que limitam o desenvolvimento produtivo das plantas. O objetivo deste trabalho foi estudar os fluxos de ar, a distribuição de temperatura e umidade relativa do ar dentro de uma estufa alternativa projetada para a produção de rosa (Rosa spp.). Três configurações de ventilação, ventilação lateral (SV), ventilação de telhado (RC) e telhado combinado e ventilação lateral (RSV) foram analisadas. O desenvolvimento metodológico baseou-se na utilização de um modelo de simulação numérica CFD-2D previamente validado, que mostrou um ajuste adequado entre os dados medidos e simulados, obtenção de valores de MAE e RMSE para temperatura e umidade relativa de 0,44 e 0,47 ° C, 3,99 e 4,04% respectivamente. Os resultados obtidos para as condições climáticas predominantes da região de estudo mostraram que as maiores taxas de ventilação foram obtidas para o RSV, com valores de 0,044 e 0,182 m 3 m -2 s -1 , essa eficiência de ventilação propiciou a geração de um microclima homogêneo, com valores de temperatura e umidade relativa adequados para a produção de rosa (Rosa spp.). Palavras-chave: Microclima, taxa de ventilação, simulação de CFD, temperatura, umidade relativa, volumes finitos.

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Section: Computational Domain and Boundary Conditionsmentioning

confidence: 99%

Study of natural ventilation in a Gothic multi-tunnel greenhouse designed to produce rose (Rosa spp.) in the high-Andean tropic

Villagrán

Bojacá

2019

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“…Moreover, the cost analysis demonstrated that the strengthening of a greenhouse structure is a very advantageous solution, as the construction cost is low, and it does not interrupt crop production. Another approach could be the evaluation of wind loads with advanced wind models [17] or Computational Fluid Dynamics (CFD) models [18][19][20][21] which may lead to less conservative wind pressures than the requirements of EN13031-1 [1] and, thus, more meticulous design and retrofitting methods.…”

Section: Discussionmentioning

confidence: 99%

Strengthening Techniques for Greenhouses

Maraveas

Tsavdaridis

2020

AgriEngineering

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Steel greenhouse structures are generally constructed by individual sole contractors using quick empirical structural calculations (pre-engineered solutions). It is also common to import standard greenhouses from other countries, mainly from The Netherlands, Italy, and France, and sometimes from Great Britain and Israel. Evidently, these countries differ concerning the local wind and snow conditions. Therefore, there is a need for a better design of structures accepted as satisfactory, while installation can be done in a different location. Many greenhouse structures incorporating poor designs or inappropriate pre-engineered solutions are currently in use. At the same time, demolition and reconstruction represent a very expensive solution considering the loss of crop production and the demolition and construction costs; thus, strengthening is a reasonable alternative. This paper presents strengthening techniques for steel greenhouses that are code-deficient according to EN 13031 and Eurocodes. Consequently, two case studies are presented as typical applications of greenhouse structure strengthening.

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“…La simulación numérica de la dinámica de fluidos computacionales (CFD) resuelve, por medio de volúmenes finitos, la forma promediada de las ecuaciones de Navier-Stokes (Kim et al, 2017). En este estudio se usó el software comercial Ansys-Fluent (Ver.…”

Section: Modelo Numérico De La Dinámica De Fluidos Computaciones (Cfd)unclassified

Ventilación natural en invernadero con mallas anti-insecto evaluadas con un modelo computacional de fluidos

2020

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Introducción. En Colombia, la producción hortícola en el trópico bajo es limitada principalmente por factores bióticos como el ataque de plagas, patógenos y factores abióticos como valores extremos de temperatura, radiación solar, viento y precipitación. Objetivo. Evaluar dos tipos de mallas anti-insecto en las áreas de ventilación de un invernadero colombiano ventilado de formado natural con el fin de analizar el efecto sobre las tasas de ventilación y el microclima generado. Materiales y métodos. El Estudio se desarrolló en el año 2019 en el departamento de Magdalena, Colombia. El enfoque metodológico incluyó el uso de modelo computacional de fluidos (CFD) 2-D para el desarrollo de quince simulaciones en estado estacionario, el modelo CFD fue validado experimentalmente en el prototipo del invernadero real evaluado. Resultados. Los parámetros de bondad de ajuste entre los datos medidos y simulados mostraron valores de error medio absoluto (MAE) y la raíz del error cuadrático medio (RMSE) para la temperatura y la humedad relativa de 0,15 y 0,32 °C, 2,41 y 2,73 %, respectivamente. Hubo una reducción promedio de las tasas de ventilación entre 55,3 y 77,1 % en comparación con el escenario de referencia que no incluyó la presencia de mallas anti-insecto, esta reducción generó modificaciones en el comportamiento de las variables temperatura y humedad relativa en el interior del invernadero, con una marcada distribución espacial heterogénea. Conclusión. Las condiciones micro climáticas más inadecuadas se presentaron en escenarios de baja velocidad de viento exterior, por lo tanto, es recomendable seleccionar e implementar algún tipo de malla anti-insecto en las áreas de ventilación de un invernadero basado en el comportamiento local de esta variable.

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Evaluation of wind pressure acting on multi-span greenhouses using CFD technique, Part 2: Application of the CFD model

Cited by 40 publications

References 26 publications

Study of natural ventilation in a Gothic multi-tunnel greenhouse designed to produce rose (Rosa spp.) in the high-Andean tropic

Study of natural ventilation in a Gothic multi-tunnel greenhouse designed to produce rose (Rosa spp.) in the high-Andean tropic

Strengthening Techniques for Greenhouses

Ventilación natural en invernadero con mallas anti-insecto evaluadas con un modelo computacional de fluidos

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