• 전기학회논문지P
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• 제65권3호
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• pp.165-170
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• 2016

Due to environmental issues such as global warming, the reduction of greenhouse gas emissions has become an inevitable measure to be taken. Among others, the building sector accounts for 50% of total carbon dioxide emissions, which is significantly high. Therefore, in order to reduce carbon dioxide emissions of the buildings, improving the energy efficiency by utilizing wind power among renewable energy sources is recommended. In case of buildings in the planning stage, it is possible to take the load of wind power generation systems into consideration when determining installed capacity. Already completed buildings, however, should be connected to small wind electric systems according to the live loads of the buildings based on the architectural design criteria. In order to connect to a building that has already been completed, it is necessary to consider the load of the small wind electric system as well as the live load of building. In addition, we need to generate the maximum electricity possible by determining the maximum installed capacity in a small area. In this paper, we propose the method for determining maximum capacity for building integrated small wind electric systems, which takes into account the considerations associated with connecting small wind electric systems to completed buildings. This can be developed into a system linked to solar power, which makes it possible to improve the energy independence of the building. In addition, carbon dioxide reduction by improving energy efficiency is expected.

• Wind and Structures
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• 제16권1호
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• pp.25-46
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• 2013

This paper presents a boundary-layer wind tunnel (BLWT) study on the effect of variable dominant openings on steady and transient responses of wind-induced internal pressure in a low-rise building. The paper presents a parametric study focusing on differences and similarities between transient and steady-state responses, the effects of size and locations of dominant openings and vent openings, and the effects of wind angle of attack. In addition, the necessity of internal volume correction during sudden breaching, i.e., a transient response experiment was investigated. A comparison of the BLWT data with ASCE 7-2010, as well as with limited large-scale data obtained at a 'Wall of Wind' facility, is presented.

• Wind and Structures
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• 제5권2_3_4호
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• pp.151-164
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• 2002

Predictions of the pedestrian level wind speeds for the downtown area of Auckland that have been obtained by wind tunnel and computational fluid dynamic (CFD) modelling are presented. The wind tunnel method involves the observation of erosion patterns as the wind speed is progressively increased. The computational solutions are mean flow calculations, which were obtained by using the finite volume code PHOENICS and the $k-{\varepsilon}$ turbulence model. The results for a variety of wind directions are compared, and it is observed that while the patterns are similar there are noticeable differences. A possible explanation for these differences arises because the tunnel prediction technique is sensitivity to gust wind speeds while the CFD method predicts mean wind speeds. It is shown that in many cases the computational model indicates high mean wind speeds near the corner of a building while the erosion patterns are consistent with eddies being shed from the edge of the building and swept downstream.

• Wind and Structures
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• 제30권1호
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• pp.99-117
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• 2020

This paper focuses on the processes of wind flow in atmospheric boundary layer, to produce realistic full scale pressures for design of low-rise buildings. CFD with LES turbulence closure is implemented on a scale 1:1 prototype building. A proximity study was executed computationally in CFD with LES that suggests new recommendations on the computational domain size, in front of a building model, apart from common RANS-based guidelines (e.g., COST and AIJ). Our findings suggest a location of the test building, different from existing guidelines, and the inflow boundary proximity influences pressure correlation and reproduction of peak loads. The CFD LES results are compared to corresponding pressures from open jet, full scale, wind tunnel, and the ASCE 7-10 standard for roof Component & Cladding design. The CFD LES shows its adequacy to produce peak pressures/loads on buildings, in agreement with field pressures, due to its capabilities of reproducing the spectral contents of the inflow at 1:1 scale.

• Wind and Structures
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• 제21권3호
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• pp.331-352
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• 2015

A series of wind tunnel tests were conducted on tapered super high-rise buildings with a square cross section by applying synchronous pressure measurement technology. The effects of global strategy of chamfered modification on aerodynamic loads and wind-induced responses were investigated. Moreover, local aerodynamic strategies of opening a ventilation slot in the corner of equipment and refuge floors were carried out. Results show that the global strategy of tapered elevation increased the vortex shedding frequency, but reduced vortex shedding energy, leading to reduction of across-wind aerodynamic loads and responses. Chamfered modification suppressed the across-wind vortex shedding effect on tapered buildings. Opening the ventilation slot further suppressed the strength of vortex shedding and reduced the residual energy related to vortex shedding in aerodynamic loads of chamfered buildings. Finally, the optimized locations of local aerodynamic strategies were suggested.

• Wind and Structures
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• 제35권3호
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• pp.157-175
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• 2022

This paper highlights the minimization of drag and lift coefficient of different types both side setback tall buildings by the multi-objective optimization technique. The present study employed 48 number both-side setback models for simulation purposes. This study adopted three variables to find the two objective functions. Setback height and setback distances from the top of building models are considered variables. The setback distances are considered between 10-40% and setback heights are within 6-72% from the top of the models. Another variable is wind angles, which are considered from 0° to 90° at 15° intervals according to the symmetry of the building models. Drag and lift coefficients according to the different wind angles are employed as the objective functions. Therefore 336 number population data are used for each objective function. Optimum models are compared with computational simulation and found good agreements of drag and lift coefficient. The design wind angle variation of the optimum models is considered for drag and lift study on the main square model. The drag and lift data of the square model are compared with the optimum models and found the optimized models are minimizing the 45-65% drag and 25-60% lift compared to the initial square model.

• 국제초고층학회논문집
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• 제11권4호
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• pp.301-314
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• 2022

Various studies have been conducted on pedestrian-level wind environments around buildings. With regard to the speed-up mechanism of pedestrian-level winds, there are references to downwash effect due to the vertical pressure gradient of boundary layer flow and venturi effect due to flow blocking by the building. Two factors contribute to increase or decrease of downwash effect: change in twodimensional / three-dimensional air flow pattern (Type 1) and change in downwash wind speed due to building size that does not accompany change in airflow pattern (Type 2). Previous studies have shown that downwash effect has a greater influence in increasing or decreasing the area of strong wind than venturi effect. However, these considerations are derived from the horizontal mean wind speed distribution at pedestrian level and are not the result of three-dimensional flow field around the building. Therefore, in this study, Computational Fluid Dynamics using Large Eddy Simulation were performed to verify the downwash phenomena that contributes to increase in wind speed at pedestrian level.

• Architectural research
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• 제18권4호
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• pp.137-144
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• 2016

The objective of this study was to determine the optimal angle of a wind louver that would induce the optimal wind speed for indoor. Being controlled to have an optimized angle depending on the direction from which wind is blowing and the wind speed, the wind louver to be installed on the building envelop comes to create indoor comfort through a constant wind speed using the function that reduces the indoor wind speed by changing the angle when the wind speed is not lower than a certain level and makes wind flow into the room to the maximum when the wind direction is adverse to catching the wind or the wind speed is not higher than a certain level. To determine the optimal wind louver angle, a core-centered office building with cross-ventilation problems in the climate of Seoul, Korea, which experiences four distinct seasons, was considered for analysis in this study. A module 1 office space model was used for the CFD simulation to analyze the average indoor wind speed with respect to the outdoor wind speed (varied between 1 and 8 m/s), the wind louver angle, and the outdoor wind direction (varied between $0^{\circ}$ and $180^{\circ}$ in steps of $10^{\circ}$).

• Wind and Structures
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• 제4권1호
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• pp.31-44
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• 2001

Mean concentrations of ammonia gas released as a tracer from an isolated low-rise building have been measured and predicted. Predictions were calculated using computational fluid dynamics (CFD) and two dispersion models: a diffusion model and a Lagrangian particle tracking technique. Explicit account was taken of the natural variation of wind direction by a technique based on the weighted summation of individual steady state wind direction results according to the probability density function of the wind direction. The results indicated that at distances >3 building heights downstream the weighted predictions from either model are satisfactory but that in the near wake the diffusion model is less successful. Weighted solutions give significantly improved predictions over unweighted results. Lack of plume spread is identified as the main cause of inaccuracies in predictions and this is linked to inadequate resolution of flow features and mixing in the CFD model. Further work on non-steady state simulation of wake flows for dispersion studies is recommended.

• Wind and Structures
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• 제3권2호
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• pp.73-81
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• 2000

Snowdrifts around buildings can cause serious problems when formed on undesirable places. The formation of snowdrifts is highly connected to the wind pattern around the building, and the wind pattern is again dependent on the building design. The shear stress on the surface and snowdrifting around different buildings are investigated through CFD analysis and compared to measurements. The computations of shear stress shows local minima in the same areas as snowdrifts are formed. The snowdrifting computations utilises a drift-flux model where a fluid with snow properties is allowed to drift through a fluid with air properties. An apparent dynamic viscosity of the snow/air mixture is defined and used as a threshold criterion for snowdrifting. The results from the snowdrifting computations show increased snow density where snowdrifts are expected, and are in agreement with previous large-scale snowdrift measurements. The results show that computational fluid dynamics can be a tool for planning building design in snowdrifting areas.