On the accuracy of CFD simulations of cross-ventilation flows for a generic isolated building: Comparison of RANS, LES and experiments

Hooff, T. van; Blocken, Bje Bert; Tominaga, Yoshihide

doi:10.1016/j.buildenv.2016.12.019

Cited by 290 publications

(159 citation statements)

References 79 publications

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“…The value of u τ is determined based on the values of the reference velocity (Uref = 7m/s) at building height (H). A time-dependent inlet profile is generated by using the vortex method with the number of vortices N = 190, and this setting was successfully tested in the previous LES validation studies for wind flows around buildings [51][52][53]. The surfaces of the house and the ground of the domain were modelled as a no-slip boundary, and at the outlet of the domain the zero-gradient condition was used [54].…”

Section: Boundary Conditions and Solver Settingmentioning

confidence: 99%

“…This scheme allows for an inner iteration to solve the individual set of equations instead of single outer iteration per time-step, which significantly speeds up the transient simulations [40]. Courant Friedrich-Lewy (CFL) condition less than 1 was used to calculate the time step required to perform the simulations and was applied to incompressible flow in previous studies [51,[55][56]. The time step was determined according to the maximum number of the Courant-Friedrich-Lewy (CFL) to avoid any numerical instability.…”

Section: Boundary Conditions and Solver Settingmentioning

confidence: 99%

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Impact of an external boundary wall on indoor flow field and natural cross-ventilation in an isolated family house using numerical simulations

Hawendi

Gao

2017

Journal of Building Engineering

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The external boundary wall is a main architectural feature of a typical residential building in Iraq, which is expected to decrease the rate of airflow entering the openings of the building. In this study, the impact of an external boundary wall on natural cross-ventilation and flow patterns inside an isolated family house was analyzed using computational fluid dynamics (CFD) simulations.The wall was located in front of the building and three different conditions were tested: basic case (without a wall) and two cases using walls of different heights. The study employed the techniques of large eddy simulation (LES) with the dynamic Smagorinsky subgrid-scale model because of the unsteady flow and high turbulence around the building. The CFD simulations were validated against the available wind tunnel experiments. It was observed that the external boundary wall created well distributed indoor air flow and improved the indoor environment regarding the mean velocity inside the building. Also, increasing the height of the wall by 20% did not offer noticeable improvement on the mean velocity distribution, whereas the ventilation airflow rate was reduced significantly to less than half when the wall was present. The results of this study are expected to inform building designers of the impact of an external boundary wall on the flow patterns in relation to the rate of ventilation and indoor mean velocity. Rate of dissipation of turbulent kinetic energy(m 2 /s 3 ) Von Karman constant Dynamic viscosity(kg/m.s) Turbulent viscosity (Pa.s) Kinematic viscosity(m 2 /s) Density(kg/m 3 ) Rate of strain tensor Subgrid-scale stress Volume of the computational cell

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Section: Boundary Conditions and Solver Settingmentioning

confidence: 99%

Section: Boundary Conditions and Solver Settingmentioning

confidence: 99%

Impact of an external boundary wall on indoor flow field and natural cross-ventilation in an isolated family house using numerical simulations

Hawendi

Gao

2017

Journal of Building Engineering

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“…Of course, in order to carry out a reliable and accurate CFD analysis, it is strictly recommended to perform validation studies based on experimentally collected measurements. For instance, in Ref , the assessment of cross ventilation of buildings is performed by means of a calibrated CFD simulation by using both 3D steady RANS simulations and large eddy simulation (LES) in a generic isolated enclosure. More in details, wind‐tunnel measurements were used for the validation of the model.…”

Section: Interaction Of Building Simulation With Other Thermal‐energymentioning

confidence: 99%

Uses of dynamic simulation to predict thermal‐energy performance of buildings and districts: a review

Castaldo

Pisello

2017

WIREs Energy & Environment

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The design of sustainable constructions also resilient to climate change has become a challenging issue given the increasing greenhouse emissions rate imputable to the built environment in urban areas. In this context, dynamic simulation models represent a suitable tool to support the design from very preliminary phases, since they allow an accurate prediction of the constructions requirements, their environmental performance, and indoor comfort conditions for their occupants. Therefore, starting from specific inputs, that is, weather conditions, construction technologies, materials, energy systems, operation settings, occupancy, and so forth, it is possible to estimate the realistic building energy performance. Moreover, the calibration procedures allow making the model even more representative of the field conditions of a construction. Given the massive progress carried out by the scientific community during the last decades, this paper presents a comprehensive review of the different building dynamic simulation approaches and available tools. While previous review studies focused on single separated aspects of dynamic simulations approaches, that is, calibration methods, software, simulation of single building energy systems, the aim of the present review is to propose a more holistic approach by investigating the recent scientific progress in simulating realistic dense urban environments. In this view, the review focus bridges the gap between the simulation at single-building level and simulation at the increasingly important neighborhood scale by showing the multiple benefits deriving from using dynamic simulation tools at district level, for a more reliable investigation of building performance in their urban context, where more than 50% of the global population worldwide currently lives.

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“…Tuan et al [30] used LES to investigate the impact of the downstream construction of terraced houses on nearby, upstream houses, and the flow patterns inside them. Recently, an in-depth comparison between five different steady RANS models and LES has been performed by van Hooff et al [31] to determine which CFD model is the most suitable for cross-ventilation flows in a generic, isolated building.…”

Section: Introductionmentioning

confidence: 99%

Impact of windward inlet-opening positions on fluctuation characteristics of wind-driven natural cross ventilation in an isolated house using LES

Hawendi

Gao

2017

International Journal of Ventilation

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On the accuracy of CFD simulations of cross-ventilation flows for a generic isolated building: Comparison of RANS, LES and experiments

Cited by 290 publications

References 79 publications

Impact of an external boundary wall on indoor flow field and natural cross-ventilation in an isolated family house using numerical simulations

Impact of an external boundary wall on indoor flow field and natural cross-ventilation in an isolated family house using numerical simulations

Uses of dynamic simulation to predict thermal‐energy performance of buildings and districts: a review

Impact of windward inlet-opening positions on fluctuation characteristics of wind-driven natural cross ventilation in an isolated house using LES

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