Numerical Study of Ventilation Flow Through a Two Dimensional Room Fitted With a Windcatcher

2011 ◽  
Author(s):  
A. R. Niktash ◽  
B. P. Huynh
Keyword(s):  
Flow Velocity ◽  
Flow Pattern ◽  
Software Package ◽  
Natural Ventilation ◽  
Numerical Study ◽  
Two Dimensional ◽  
Inlet Velocity ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through ◽  
Living Area

A windcatcher is a natural ventilation device fitted on the roof of a building and divided internally into two halves to deliver fresh outside air into the building’s interior, and induce the stale air to the outside, working by pressure difference between outside and inside of the building. In this work, air flow through a two-dimensional but real-sized room fitted with a windcatcher is investigated numerically, using a commercial computational fluid dynamics (CFD) software package. The standard K-ε turbulence model is used. Flow pattern and flow velocity are considered in terms of the windcatcher’s location, inlet velocity, the shape of the windcatcher’s bottom and the length of the windcatcher’s bottom. It is found that when inlet velocity is not too low, the windcatcher’s shape at its bottom strongly affects flow pattern and flow velocity in the room. This leads to a way of improving the windcatcher’s effectiveness in ventilating the living area (lower part) of a room.

Numerical Simulation and Analysis of the Two-Sided Windcatcher Inlet\Outlet Effect on Ventilation Flow Through a Three Dimensional Room

2014 ◽  
Author(s):  
Amirreza Niktash ◽  
B. P. Huynh
Keyword(s):  
Flow Velocity ◽  
Flow Pattern ◽  
Natural Ventilation ◽  
Three Dimensional ◽  
Interior Space ◽  
Different Types ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through ◽  
Cfd Method ◽  
Living Area

A windcatcher is a structure placed on the roof of a building for providing natural ventilation for interior space working by wind power. It draws out the inside stale air to the outside and supplies the outside fresh air for the building’s interior space. In this paper, the effect of different types of windcatcher’s inlet\outlet on the air flow, flow velocity and flowrate through a three-dimensional room fitted with a two-sided windcatcher is observed numerically, using a commercial computational fluid dynamics (CFD) software package. The standard RANS K-ε CFD method is used in the simulations. The flow pattern, flow velocity and flowrate of the inside ventilation flow is considered for the six different types of a two-sided windcatcher’s inlet\outlet. It is found that the shape of the inlet\outlet of windcatcher strongly affects flow pattern, flow velocity and flowrate and the performance of square windcatcher is higher than the circular one specially in ventilating the living area (lower part) of a room.

The Effect of Bench Arrangements on the Natural Ventilation of a Multispan Greenhouse

2013 ◽  
Author(s):  
Sunita Kruger ◽  
Leon Pretorius
Keyword(s):  
Fluid Dynamics ◽  
Natural Ventilation ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Low Velocity ◽  
Lower Velocity ◽  
Cfd Models ◽  
Temperature Distributions ◽  
Computational Fluid Dynamics Cfd ◽  
Plant Level

In this paper, the influence of various bench arrangements on the microclimate inside a two-span greenhouse is numerically investigated using three-dimensional Computational Fluid Dynamics (CFD) models. Longitudinal and peninsular arrangements are investigated for both leeward and windward opened roof ventilators. The velocity and temperature distributions at plant level (1m) were of particular interest. The research in this paper is an extension of two-dimensional work conducted previously [1]. Results indicate that bench layouts inside the greenhouse have a significant effect on the microclimate at plant level. It was found that vent opening direction (leeward or windward) influences the velocity and temperature distributions at plant level noticeably. Results also indicated that in general, the leeward facing greenhouses containing either type of bench arrangement exhibit a lower velocity distribution at plant level compared to windward facing greenhouses. The latter type of greenhouses has regions with relatively high velocities at plant level which could cause some concern. The scalar plots indicate that more stagnant areas of low velocity appear for the leeward facing greenhouses. The windward facing greenhouses also display more heterogeneity at plant level as far as temperature is concerned.

scholarly journals Numerical Analysis of Fluid Flow on Wall Cylinder Circular with K-ε Modeling for a High Reynolds Rate

2019 ◽  
Vol 1 (3) ◽  
pp. 43-50
Author(s):  
M. Yasep Setiawan ◽  
Wawan Purwanto ◽  
Wanda Afnison ◽  
Nuzul Hidayat
Keyword(s):  
Fluid Flow ◽  
Numerical Study ◽  
General Procedure ◽  
Circular Cylinders ◽  
Cylinder Wall ◽  
Two Dimensional ◽  
Third Order ◽  
Physical Information ◽  
Flow Through ◽  
High Reynolds

This study discusses the numerical study of two-dimensional analysis of flow through circular cylinders. The original physical information entered in the equation governing most of the modeling is transferred into a numerical solution. Fluid flow on two-dimensional circular cylinder wall using high Reynolds k-ε modeling (Re = 106), Here we will do 3 modeling first oder upwind, second order upwind and third order MUSCL by using k-ε standard.  The general procedure for this research is formulated in detail for allocations in the dynamic analysis of fluid computing. The results of this study suggest that MUSCL's third order modeling gives more accurate results better than other models.

scholarly journals Numerical Study of Flow Characteristics Around Confined Cylinder using OpenFOAM

2018 ◽  
Vol 7 (4.35) ◽  
pp. 617
Author(s):  
P. Mathupriya ◽  
L. Chan ◽  
H. Hasini ◽  
A. Ooi
Keyword(s):  
Reynolds Number ◽  
Vortex Shedding ◽  
Numerical Study ◽  
Vortex Formation ◽  
Plane Channel ◽  
Flow Characteristics ◽  
Strong Interactions ◽  
Two Dimensional ◽  
Computational Fluid Dynamics Cfd ◽  
Shedding Frequency

The numerical study of the flow over a two-dimensional cylinder which is symmetrically confined in a plane channel is presented to study the characteristics of vortex shedding. The numerical model has been established using direct numerical simulation (DNS) based on the open source computational fluid dynamics (CFD) code named OpenFOAM. In the present study, the flow fields have been computed at blockage ratio, β of 0.5 and at Reynolds number, Re of 200 and 300. Two-dimensional simulations investigated on the effects of Reynolds number based on the vortex formation and shedding frequency. It was observed that the presence of two distinct shedding frequencies appear at higher Reynolds number due to the confinement effects where there is strong interactions between boundary layer, shear layer and the wake of the cylinder. The range of simulations conducted here has shown to produce results consistent with that available in the open literature. Therefore, OpenFOAM is found to be able to accurately capture the complex physics of the flow.

scholarly journals ICCM2015: A Comparison of RANS and LES Computational Methods in Analyzing Ventilation Flow Through a Room Fitted with a Two-Sided Windcatcher

2017 ◽  
Vol 14 (03) ◽  
pp. 1750021 ◽  
Author(s):  
A. Niktash ◽  
B. P. Huynh
Keyword(s):  
Natural Ventilation ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Interior Space ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through ◽  
Cfd Method ◽  
Good Agreement

A windcatcher is a structure for providing natural ventilation using wind power; it is usually fitted on the roof of a building to exhaust the inside stale air to the outside and supplies the outside fresh air into the building interior space working by pressure difference between outside and inside of the building. In this paper, the behavior of free wind flow through a three-dimensional room fitted with a centered position two-canal bottom shape windcatcher model is investigated numerically, using a commercial computational fluid dynamics (CFD) software package and LES (Large Eddy Simulation) CFD method. The results have been compared with the obtained results for the same model but using RANS (Reynolds Averaged Navier–Stokes) CFD method. The model with its surrounded space has been considered in both method. It is found that the achieved results for the model from LES method are in good agreement with RANS method’s results for the same model.

scholarly journals Numerical Study of Flow Pattern in Buildings with Different Heights

2016 ◽  
Vol 2 (3) ◽  
pp. 95-101
Author(s):  
Ali Hooshmand Aini
Keyword(s):  
Flow Pattern ◽  
Natural Ventilation ◽  
Numerical Study ◽  
Flow Patterns ◽  
Accurate Analysis ◽  
Air Movement ◽  
Fluent Software

Understanding the flow pattern around the building, results in an accurate analysis of structure performance. Furthermore, having a proper configuration of the buildings next to each other we can provide a situation in which the buildings use the wind to make the air movement and natural ventilation. In this paper we use the FLUENT software to verify numerical flow pattern in buildings with different heights, and the results are provided in the form of distribution of velocities, velocity in Y direction, flow patterns and counters of turbulent.  

Computational Study of Single-Sided Ventilation Through a 3-Dimensional Room With Rounded Edges

2013 ◽  
Author(s):  
A. Idris ◽  
B. P. Huynh
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Speed ◽  
Flow Pattern ◽  
Flow Rate ◽  
Software Package ◽  
Computational Study ◽  
Ventilation Rate ◽  
3 Dimensional ◽  
Computational Fluid Dynamics Cfd

A commercial Computational Fluid Dynamics (CFD) software package is used to investigate numerically a 3-dimensional rectangular-box room with rounded edges. The room has all its window openings located on one wall only. The standard K-ε turbulence model is used. Air’s flow rate and flow pattern are considered in terms of wind speed and the openings’ characteristics, such as their number, location, size and shape. Especially, comparison with ventilation rate corresponding to when the room edges are sharp is made; and thereby the effects of the edges being rounded are examined.

scholarly journals Numerical Study on the Characteristics of Boger Type Viscoelastic Fluid Flow in a Micro Cross-Slot under Sinusoidal Stimulation

Entropy ◽  
2020 ◽  
Vol 22 (1) ◽  
pp. 64
Author(s):  
Chao Yuan ◽  
Hong-Na Zhang ◽  
Li-Xia Chen ◽  
Jun-Long Zhao ◽  
Xiao-Bin Li ◽  
...  
Keyword(s):  
Flow Pattern ◽  
Natural Frequency ◽  
Viscoelastic Fluid ◽  
Numerical Study ◽  
Nonlinear Effects ◽  
Weissenberg Number ◽  
Stimulation Frequency ◽  
External Stimulation ◽  
Inlet Velocity ◽  
The Cross

The cross-slot geometry plays an important role in the study of nonlinear effects of viscoelastic fluids. The flow of viscoelastic fluid in a micro cross-slot with a high channel aspect ratio (AR, the ratio of channel depth to width) can be divided into three types, which are symmetric flow, steady-state asymmetric flow and time-dependent flow under the inlet condition with a constant velocity. However, the flow pattern of a viscoelastic fluid in the cross-slot when a stimulation is applied at inlets has been rarely reported. In this paper, the response of cross-slot flow under an external sinusoidal stimulation is studied by numerical simulations of a two-dimensional model representing the geometry with a maximum limit of AR. For the cases under constant inlet velocity conditions, three different flow patterns occur successively with the increase of Weissenberg number (Wi). For the cases under sinusoidal varying inlet velocity conditions, when the stimulation frequency is far away from the natural frequency of a viscoelastic fluid, the frequency spectrum of velocity fluctuation field shows the characteristics of a fundamental frequency and several harmonics. However, the harmonic frequency disappears when the stimulation frequency is close to the natural frequency of the viscoelastic fluid. Besides, the flow pattern shows spatial symmetry and changes with time. In conclusion, the external stimulation has an effect on the flow pattern of viscoelastic fluid in the 2D micro cross-slot channel, and a resonance occurs when the stimulation frequency is close to the natural frequency of the fluid.

scholarly journals Unsteady flow through a cascade of aerofoils

1960 ◽  
Vol 1 (2) ◽  
pp. 220-232 ◽  
Author(s):  
A. H. Low ◽  
L. C. Woods
Keyword(s):  
Unsteady Flow ◽  
Two Dimensional ◽  
Inlet Velocity ◽  
Flow Through ◽  
Transient Forces

SummaryThis paper extends some earlier work by Woods [8] on the transient forces caused by unsteady transverse motions of a rigid cascade of aerofoils to the case when the inlet velocity is varying in magnitude. The flow is incompressible and two-dimensional. Expressions for the growth of lift and moment on a member of the cascade with increasing inlet velocity are evaluated and shown to be generalizations of Wagner's classical results for an isolated aerofoil.

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