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Author: Caesar Wiratama Abstract Wind-driven natural convection plays an important role in indoor airflow, thermal comfort, and ventilation performance in naturally ventilated houses. This study presents a CFD analysis of external wind-induced natural ventilation in a residential building using OpenFOAM with a standardized tensorHVAC workflow. The simulations capture airflow circulation, temperature distribution, and ventilation effectiveness Read more

Author: Caesar Wiratama Abstract Computational Fluid Dynamics (CFD) is increasingly used in HVAC design to evaluate airflow distribution, thermal comfort, and ventilation effectiveness. However, the complexity of OpenFOAM case setup often limits its adoption in practical HVAC applications. This study presents an HVAC CFD simulation framework based on OpenFOAM using the tensorHVAC template, which standardizes Read more

Author: Caesar Wiratama Abstract Computational Fluid Dynamics (CFD) is increasingly applied in HVAC design to evaluate airflow distribution, thermal comfort, and ventilation effectiveness. In this study, an HVAC CFD workflow based on OpenFOAM using the tensorHVAC template is presented and applied to a small café case study. Three indoor unit placement configurations were investigated using Read more

Author: Caesar Wiratama ([email protected]) Abstract. Sieve trays act as vital gas–liquid contact devices in distillation columns. In this study, a three-dimensional, two-phase Computational Fluid Dynamics (CFD) model employing the Volume of Fluid (VOF) method was developed tosimulate a distillation column containing two sieve trays, explicitly accounting for vapor–liquid phase change. Keyhydrodynamic parameters—such as velocity profiles, Read more

The standard κ-ω model involves modifications considering low Reynolds number effects, compressibility, and shear flow spreading based on Wilcox’s modeling. One drawback of the Wilcox model is its sensitivity in regions outside the shear layer (in the free stream area). The standard κ-ω model is an empirical modeling approach based on the transport equations of Read more

In this chapter, two κ-ω equation models will be explained: the standard model and the Shear-Stress Transport (SST) model. Both models share similarities, yet there are two main differences between them: Unlike the κ-ε model, which is tailored for high Reynolds numbers, Wilcox’s κ-ω model is based on low Reynolds numbers. Reference: Caesar Wiratama. Theory Read more

There are two main differences between the realizable κ-ε model and the standard κ-ε model: The term “realizable” implies that the model satisfies certain mathematical constraints on Reynolds stresses, consistent with the physical phenomena of turbulent flow. One drawback of the realizable κ-ε model is that its computations produce inaccurate turbulent viscosity when the computational Read more

The RNG κ-ε turbulence model isn’t significantly different from the standard model. It’s derived using a statistical technique called renormalization group theory (RNG) and differs from the standard model in the following ways: Here are the transport equations for the RNG κ-ε turbulence model: (6.8) And (6.9) Not significantly different from the standard equations, but Read more

The two-equation turbulence models calculate turbulent length and time scales by solving two separate transport equations. The standard κ-ε model is part of these two-equation models and has been widely used in the engineering world concerning fluid flow since its inception by Launder and Spalding. Its capability to handle a wide range of cases, moderate Read more

The standard κ-ε model, RNG κ-ε model, and the realizable κ-ε model all have the same form of transport equations for κ and ε. The fundamental differences among these models include: Reference: Caesar Wiratama. Theory and Best Practices of Computational Fluid Dynamics. PT Tensor Karya Nusantara, Yogyakarta. 2025 Read more