On the feasibility of using open source solvers for the simulation of a turbulent air flow in a dairy barn

Janke, David; Caiazzo, Alfonso; Ahmed, Naveed; Alia, Najib; Knoth, Oswald; Moreau, Baptiste; Wilbrandt, Ulrich; Willink, Dilya; Amon, Thomas; John, Volker

doi:10.1016/j.compag.2020.105546

Cited by 11 publications

(9 citation statements)

References 25 publications

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“…Reynolds number of ~37.000 was achieved for the inside flow of the model, which is published in a previous study with the same model [26]. This meets the requirements of the internal Reynolds number independence on the flow within the model [27], making the wind tunnel results up scalable.…”

Section: Description Of the Wind Tunnel And A Scale Model Of Nvd Buildingsupporting

confidence: 58%

“…The inflow profile was fulfilled the criteria for a boundary layer over a moderately rough terrain according to the VDI guideline for Physical Modelling of Flow and Dispersion Processes in the Atmospheric Boundary Layer [25]. With the barn model height as characteristic length and the local velocities at the barn, a Reynolds number of~37.000 was achieved for the inside flow of the model, which is published in a previous study with the same model [26]. This meets the requirements of the internal Reynolds number independence on the flow within the model [27], making the wind tunnel results up scalable.…”

Section: Methodsmentioning

confidence: 99%

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Opening Size Effects on Airflow Pattern and Airflow Rate of a Naturally Ventilated Dairy Building—A CFD Study

Saha

Janke

et al. 2020

Applied Sciences

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Airflow inside naturally ventilated dairy (NVD) buildings is highly variable and difficult to understand due to the lack of precious measuring techniques with the existing methods. Computational fluid dynamics (CFD) was applied to investigate the effect of different seasonal opening combinations of an NVD building on airflow patterns and airflow rate inside the NVD building as an alternative to full scale and scale model experiments. ANSYS 2019R2 was used for creating model geometry, meshing, and simulation. Eight ventilation opening combinations and 10 different reference air velocities were used for the series of simulation. The data measured in a large boundary layer wind tunnel using a 1:100 scale model of the NVD building was used for CFD model validation. The results show that CFD using standard k-ε turbulence model was capable of simulating airflow in and outside of the NVD building. Airflow patterns were different for different opening scenarios at the same external wind speed, which may affect cow comfort and gaseous emissions. Guiding inlet air by controlling openings may ensure animal comfort and minimize emissions. Non-isothermal and transient simulations of NVD buildings should be carried out for better understanding of airflow patterns.

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Section: Description Of the Wind Tunnel And A Scale Model Of Nvd Buildingsupporting

confidence: 58%

Section: Methodsmentioning

confidence: 99%

Opening Size Effects on Airflow Pattern and Airflow Rate of a Naturally Ventilated Dairy Building—A CFD Study

Saha

Janke

et al. 2020

Applied Sciences

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“…The presented work was carried out using the opensource CFD code OpenFOAM in order to have freedom in the implementation of new solutions and models. This CFD simulation code has already been employed and validated for the simulation of a livestock building [22,23], even if all applications reported in the literature refer to naturally or mechanically ventilated barns.…”

Section: Motivation Objective and Analysed Case Studymentioning

confidence: 99%

A CFD Methodology for the Modelling of Animal Thermal Welfare in Hybrid Ventilated Livestock Buildings

Colombari,

Masoero,

Della Torre

2024

AgriEngineering

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Computational fluid dynamics (CFD) may aid the design of barn ventilation systems by simulating indoor cattle thermal welfare. In the literature, CFD models of mechanically and naturally ventilated barns are proposed separately. Hybrid ventilation relies on cross effects between air change mechanisms that cannot be studied using existing models. The objective of this study was to develop a CFD methodology for modelling animal thermal comfort in hybrid ventilated barns. To check the capability of CFD as a design evaluation tool, a real case study (with exhaust blowers) and an alternative roof layout (with ridge gaps) were simulated in summer and winter weather. Typical phenomena of natural and mechanical ventilation were considered: buoyancy, solar radiation, and wind together with high-speed fans and exhaust blowers. Cattle thermal load was determined from a daily animal energy balance, and the assessment of thermal welfare was performed using thermohygrometric indexes. Results highlight that the current ventilation layout ensures adequate thermal welfare on average, despite large nonuniformity between stalls. The predicted intensity of heat stress was successfully compared with experimental measurements of heavy breathing duration. Results show strong interactions between natural and mechanical ventilation, underlining the need for an integrated simulation methodology.

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“…The dimensions of the numerical domain are summarized in Figure 1. The characteristic lengths, such the width W and the height H, are based on the ATB barn sizes in Northern Germany [14], W = 34.2 m, H = 11.5 m. The inlet velocity describes an atmospheric boundary layer (ABL) profile with the equation [15]:…”

Section: Domain and Boundary Conditionmentioning

confidence: 99%

“…The dimensions of the each AOZ are L AOZ = W/2, W AOZ = W/4 and disposed as shown in green in Figure 1. According to the density 2.4 m 2 cow −1 (taken from the aforementioned barn in Northern Germany; for a detailed barn description, see, e.g., Janke et al [14]); the number of cows for the AOZ dimensions is 33. Using the method descripted in Doumbia et al [13], the AOZ was replaced by a porous medium with the corresponding pressure drop (in the three main directions) and heat transfer functions extracted from the 33 cows 3D geometry (randomly distributed with a ratio of 60% lying and 40% standing) numerical simulation.…”

Section: Domain and Boundary Conditionmentioning

confidence: 99%

A Parametric Model for Local Air Exchange Rate of Naturally Ventilated Barns

Doumbia

Janke

et al. 2021

Agronomy

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With an increasing number of naturally ventilated dairy barns (NVDBs), the emission of ammonia and greenhouse gases into the surrounding environment is expected to increase as well. It is very challenging to accurately determine the amount of gases released from a NVDB on-farm. Moreover, control options for the micro-climate to increase animal welfare are limited in an NVDB at present. Both issues are due to the complexity of the NVDB micro-environment, which is subject to temporal (such as wind direction and temperature) and spatial (such as openings and animals acting as airflow obstacles) fluctuations. The air exchange rate (AER) is one of the most valuable evaluation entities, since it is directly related to the gas emission rate and animal welfare. In this context, our study determined the general and local AERs of NVDBs of different shapes under diverse airflow conditions. Previous works identified main influencing parameters for the general AER and mathematically linked them together to predict the AER of the barn as a whole. The present research study is a continuation and extension of previous studies about the determination of AER. It provides new insights into the influence of convection flow regimes. In addition, it goes further in precision by determining the local AERs, depending on the position of the considered volume inside the barn. After running several computational fluid dynamics (CFD) simulations, we used the statistical tool of general linear modeling in order to identify quantitative relationships between the AER and the following five influencing parameters, the length/width ratio of the barn, the side opening configuration, the airflow temperature, magnitude and incoming direction. The work succeeded in taking the temperature into account as a further influencing parameter in the model and, thus, for the first time, in analysing the effect of the different types of flow convection in this context. The resulting equations predict the barn AER with an R2 equals 0.98 and the local AER with a mean R2 equals around 0.87. The results go a step further in the precise determination of the AER of NVDB and, therefore, are of fundamental importance for a better and deeper understanding of the interaction between the driving forces of AER in NVDB.

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On the feasibility of using open source solvers for the simulation of a turbulent air flow in a dairy barn

Cited by 11 publications

References 25 publications

Opening Size Effects on Airflow Pattern and Airflow Rate of a Naturally Ventilated Dairy Building—A CFD Study

Opening Size Effects on Airflow Pattern and Airflow Rate of a Naturally Ventilated Dairy Building—A CFD Study

A CFD Methodology for the Modelling of Animal Thermal Welfare in Hybrid Ventilated Livestock Buildings

A Parametric Model for Local Air Exchange Rate of Naturally Ventilated Barns

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