Effect of Temperature on Greenhouse Natural Ventilation under Hot Conditions: Computational Fluid Dynamics Simulations

2008 ◽  
Vol 8 (24) ◽  
pp. 4543-4551 ◽  
Author(s):  
E. Rico-Garci ◽  
I.L. Lopez-Cruz ◽  
G. Herrera-Ru ◽  
G.M. Soto-Zaraz ◽  
R. Castaneda-
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Natural Ventilation ◽  
Effect Of Temperature ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations

Parametric analysis of the wind-driven ventilation potential of buildings with rectangular layout

2018 ◽  
Vol 40 (1) ◽  
pp. 109-128 ◽  
Author(s):  
Margherita Ferrucci ◽  
Maurizio Brocato
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Aspect Ratio ◽  
Pressure Difference ◽  
Natural Ventilation ◽  
Pressure Field ◽  
Existing Buildings ◽  
Decision Tools ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations

A method to evaluate the wind-driven ventilation potential of buildings is proposed and some schematic examples are given. Two indicators of such potential are put forward: the first concerning the pressure difference between spots (openings) on the facades and the second concerning the ratio between this pressure difference and a simplified measure of the pressure loss by the internal air flow. These indicators allow one to compare shapes and orientations and can help finding the most appropriate ones during a preliminary stage of the design of a naturally ventilated building. To present the proposal, a two-dimensional computational fluid dynamics parametric model of a schematic building is set, the parameters of which are the aspect ratio of the building's rectangular plan and the wind relative direction. The computational fluid dynamics simulations are supported by literature benchmarks and by qualitative experiments in a wind tunnel. Using this model, the pressure field is computed for 66 cases and their ventilation potentials are evaluated; some graphic outputs are then proposed for a preliminary understanding of the pressure field and of the resulting indicators. The optimal morphology given by such analyses is finally compared to that of some naturally ventilated existing buildings, including Iranian badgir towers. Practical application: This paper provides graphs to predict a building's potential for natural ventilation thereby enabling a designer to determine the wind-driven ventilation in a building and evaluate the structure, optimise its orientation, its aspect ratio and opening positions. These can be used, for example, in the evaluation of naturally ventilated multi-storey rectangular plan buildings (that might employ hyper-ventilation or night cooling) or to evaluate possible passive ventilation strategies for existing buildings. With the support of these graphs, which can be used as computationally inexpensive and fast decision tools, it is possible to simulate configurations, considering the parameters that most influence natural ventilation.

scholarly journals COMPARISON OF AIRFLOW IN TYPE 36 LOW-INCOME HOUSING UNIT USING CFD SIMULATION

2021 ◽  
Vol 48 (2) ◽  
pp. 121-130
Author(s):  
Lestari Lestari ◽  
Syaiful Muazir
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Indoor Air ◽  
Low Income ◽  
Natural Ventilation ◽  
Cfd Simulation ◽  
Building Design ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations

Type 36 houses are built for people who have low income. Because of this, the buildings’ ventilation relies on natural airflow. One of the variables that affects natural ventilation is airflow. Airflow can affect the quality of indoor air, influencing the comfort and health of those within. This study aims to evaluate the designs of type 36 buildings from the perspective of the airflow through the unit. It uses computational fluid dynamics simulations to compare the pattern and velocity of airflow in each building design. There are six designs of type 36 house that have different layouts and placements of air vents. The results of the simulation and analysis show that rooms arranged in a way that allows for the placement of vents that were facing each other, even if they were in different rooms, generated continuous airflow without experiencing turbulence.

scholarly journals Aerodynamic analysis of uphill drafting in cycling

2021 ◽  
Vol 24 (1) ◽  
Author(s):  
T. van Druenen ◽  
B. Blocken
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Speed ◽  
Scientific Literature ◽  
Sensitivity Analyses ◽  
Air Resistance ◽  
Wind Tunnel Measurements ◽  
Aerodynamic Effect ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations

AbstractSome teams aiming for victory in a mountain stage in cycling take control in the uphill sections of the stage. While drafting, the team imposes a high speed at the front of the peloton defending their team leader from opponent’s attacks. Drafting is a well-known strategy on flat or descending sections and has been studied before in this context. However, there are no systematic and extensive studies in the scientific literature on the aerodynamic effect of uphill drafting. Some studies even suggested that for gradients above 7.2% the speeds drop to 17 km/h and the air resistance can be neglected. In this paper, uphill drafting is analyzed and quantified by means of drag reductions and power reductions obtained by computational fluid dynamics simulations validated with wind tunnel measurements. It is shown that even for gradients above 7.2%, drafting can yield substantial benefits. Drafting allows cyclists to save over 7% of power on a slope of 7.5% at a speed of 6 m/s. At a speed of 8 m/s, this reduction can exceed 16%. Sensitivity analyses indicate that significant power savings can be achieved, also with varying bicycle, cyclist, road and environmental characteristics.

scholarly journals Evaluation of Active Heat Sinks Design under Forced Convection—Effect of Geometric and Boundary Parameters

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2041
Author(s):  
Eva C. Silva ◽  
Álvaro M. Sampaio ◽  
António J. Pontes
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Additive Manufacturing ◽  
Pressure Drop ◽  
Forced Convection ◽  
Thermal Performance ◽  
Heat Sinks ◽  
Trapezoidal Shape ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations

This study shows the performance of heat sinks (HS) with different designs under forced convection, varying geometric and boundary parameters, via computational fluid dynamics simulations. Initially, a complete and detailed analysis of the thermal performance of various conventional HS designs was taken. Afterwards, HS designs were modified following some additive manufacturing approaches. The HS performance was compared by measuring their temperatures and pressure drop after 15 s. Smaller diameters/thicknesses and larger fins/pins spacing provided better results. For fins HS, the use of radial fins, with an inverted trapezoidal shape and with larger holes was advantageous. Regarding pins HS, the best option contemplated circular pins in combination with frontal holes in their structure. Additionally, lattice HS, only possible to be produced by additive manufacturing, was also studied. Lower temperatures were obtained with a hexagon unit cell. Lastly, a comparison between the best HS in each category showed a lower thermal resistance for lattice HS. Despite the increase of at least 38% in pressure drop, a consequence of its frontal area, the temperature was 26% and 56% lower when compared to conventional pins and fins HS, respectively, and 9% and 28% lower when compared to the best pins and best fins of this study.

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