Improvement of k-epsilon turbulence model for CFD simulation of atmospheric boundary layer around a high-rise building using stochastic optimization and Monte Carlo Sampling technique

Shirzadi, Mohammadreza; Mirzaei, Parham A.; Naghashzadegan, Mohammad

doi:10.1016/j.jweia.2017.10.005

Cited by 93 publications

(42 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As mentioned in the introduction, the choice of a turbulence model has a major impact on the estimation of the turbulence scale of the flow around the evaporators. The RANS turbulence models, such as the realisable k-ε model applied in the present study, generally overestimate the wake region behind buildings, as summarised by Shirzadi et al [28]. The prediction of the RANS simulation can be improved by changing the semi-empirical coefficients of the turbulence models.…”

mentioning

confidence: 52%

Analysis of Cold Air Recirculation in the Evaporators of Large-Scale Air-Source Heat Pumps Using CFD Simulations

Rogié

Jensen

Hansen

et al. 2020

Fluids

View full text Add to dashboard Cite

The present study investigates cold air recirculation in the evaporators of large-scale air-source heat pumps. A case study considered a 5 MW air-source heat pump producing heat for district heating. The heat pump comprises 20 horizontal evaporators, where each evaporator is equipped with eight fans. The evaporators were implemented in a CFD model, where the influence of the outdoor wind direction on the recirculation was investigated. Firstly, the air recirculation was analysed with no surrounding obstacles. Secondly, the surrounding building and the real ground topology was included in the CFD model, to analyse their influence on the air recirculation. The results show that recirculation occurs for all wind directions, due to the turbulent behaviour of the flow around the evaporators. The results also show that the presence of a building intensifies the recirculation when it is placed directly upstream of the evaporators due to the presence of vortices in the wake of the building. On the other hand, a ground depression helps to reduce the recirculation by having additional energy dissipation due to the sudden change in the ground direction.

show abstract

mentioning

confidence: 52%

Analysis of Cold Air Recirculation in the Evaporators of Large-Scale Air-Source Heat Pumps Using CFD Simulations

Rogié

Jensen

Hansen

et al. 2020

Fluids

View full text Add to dashboard Cite

show abstract

“…The commercial CFD code Ansys Fluent 17.0 is used to solve the three-dimensional (3D) RANS equations, and closure is obtained using the standard k − ε (SKE) with LK modification (Kato and Launder, 1993) with the closure coefficient proposed by Shirzadi et al (2017). These closure coefficients provide sufficient accuracy to simulate flow in the wake region.…”

Section: Methodsmentioning

confidence: 99%

Investigation of pedestrian-level wind environment near two high-rise buildings in different arrangements

Sharma

Gairola

2019

Advances in Structural Engineering

View full text Add to dashboard Cite

The presence of buildings that surround the wind environment adversely affects at the pedestrian level. The present study investigates the effect of different arrangement of two buildings on wind flow structure and modification of wind speed conditions at the pedestrian level. The investigation was carried out for parallel, tandem, and staggered arrangement of two buildings using computational fluid dynamics simulations. The wind tunnel experiments were conducted to validate the computational fluid dynamics results. The computational fluid dynamics simulations were performed using the standard [Formula: see text] model with LK modification and revised closure coefficients. Different flow features such as skew-symmetric vortex structure for parallel arrangement, reattachment of shear layer on the surfaces of the downstream building for tandem arrangement, and deviation of wake region behind the upstream building to leftward of the flow direction for staggered arrangement were observed. It was observed that the strong wind conditions were mostly affected by tandem and parallel location of the twin buildings. The results of numerical simulation obtained using the modified SKE model were found to be in good agreement with the experimental results.

show abstract

“…Since many studies have already reported that the k-ε model is appropriate for flow analysis in order to simulate turbulent jets [15,22,23], our study also used the k-ε model. In this model, k and ε are expressed in their respective transport equations as follows [23,24]:…”

Section: Numerical Modelingmentioning

confidence: 99%

Numerical Simulation and Validation in Scrubber Wash Water Discharge from Ships

Choi

Lim

2020

JMSE

View full text Add to dashboard Cite

A regulation on the sulfur emissions of ships sailing in global sea areas has been enforced since 1 January 2020. In this new regulation, ships are required to use low-sulfur fuel oils or to install an after-treatment equipment, such as a scrubber. Open and hybrid scrubbers wash the exhaust gas using seawater and then discharge the wash water overboard. According to the regulation promulgated by the International Maritime Organization (IMO) Marine Environment Protection Committee (MEPC), the wash water must have a pH of 6.5 or higher at 4 m from the discharge point. Wash water is generally acidic, with a pH of 2.5–3.5, whereas seawater is alkaline, with a pH of approximately 8.2. The wash water is dispersed after being discharged overboard through a nozzle, and its pH is restored through dilution with the surrounding seawater. In this study, the pH was calculated by using a theoretical chemical reaction model, and then the dispersion of wash water was analyzed using CFD simulation. This study describes the process of selecting the appropriate turbulent Schmidt number in a wide range of nozzle diameters. Finally, the appropriate nozzle diameter was determined based on the initial pH of the discharged scrubber wash.

show abstract

Improvement of k-epsilon turbulence model for CFD simulation of atmospheric boundary layer around a high-rise building using stochastic optimization and Monte Carlo Sampling technique

Cited by 93 publications

References 64 publications

Analysis of Cold Air Recirculation in the Evaporators of Large-Scale Air-Source Heat Pumps Using CFD Simulations

Analysis of Cold Air Recirculation in the Evaporators of Large-Scale Air-Source Heat Pumps Using CFD Simulations

Investigation of pedestrian-level wind environment near two high-rise buildings in different arrangements

Numerical Simulation and Validation in Scrubber Wash Water Discharge from Ships

Contact Info

Product

Resources

About