CFD Benchmark Tests for Indoor Environmental Problems: Part 2 Cross-Ventilation Airflows and Floor Heating Systems

Abstract

Commercial Computational Fluid Dynamics (CFD) software is practically applied in indoor environmental design recent years but the prediction accuracy of CFD simulation depends on the understanding for the fundamentals of fluid dynamics and the setting of appropriate boundary and numerical conditions as well. Additionally, deeper understanding to a specific problem regarding indoor environment is also requested. The series of this study aimed to provide with the practical information such as prediction accuracy and problematic areas related to CFD applications in indoor environment, air conditioning and ventilation, then performed benchmark tests and reported the results. In this Part 2, benchmark test results for cross-ventilation airflows and floor heating systems were introduced. The highest reproducibility of the predicted results compared with the wind tunnel results occurred when the Z0-type wall function was used as the floor-surface boundary condition and the SST k–ω for the turbulence model in case of cross-ventilation flow and SST k–ω model showed also the closest matching results with experiment in case of natural convection in a room with floor heating.

Numerical prediction of tissue dosimetry in respiratory tract using computer simulated person integrated with physiologically based pharmacokinetic–computational fluid dynamics hybrid analysis

“…Previous benchmark tests have used CFD to predict flow field characteristics in combination with air temperature in the nasal cavity under various conditions. 45,48–51 This article also used the low Reynolds number type k-ɛ model (the Abe-Kondoh-Nagano model) in order to analyse the flow pattern inside the respiratory tract. The mesh inside the virtual airway was generated with tetrahedral cells and the total number of cells was set to 7.5 million.…”

First- and second-hand smoke dispersion analysis from e-cigarettes using a computer-simulated person with a respiratory tract model

“…Furthermore, a grid independence check was executed carefully and elaborately and the minimum mesh size near the wall surface, skewness, and size ratio of adjoining meshes were elaborately designed, especially for the room model with the CSP. 40–43 Concerning the respiratory tract model, we have already reported the grid independence check results and the validation results according to experimental data. 21,29…”

Folded roof house—Design solution to optimize environmental conditions with generic equipment and techniques

“…The following performances were analyzed with environmental simulation techniques: (i) Optimization of the window opening position by solar radiation and indoor light environment analysis; (ii) Natural/cross-ventilation design supported by computational fluid dynamics (CFD) simulation [10][11][12] ; (iii) Optimization of opening position of horizontal slit-type windows using wind pressure coefficient analysis with CFD; and (iv) Annual heat load calculations to optimize the thermal insulation and natural/mechanical ventilation. Since the numerical simulation/analysis tools provide deterministic information for environmental conditions, the flexibility of design might decrease greatly when aiming at environmental optimization.…”