DescriptionExternal Flow around an Atrium is a complete, start-to-finish CFD training project that examines how horizontal wind interacts with an architectural atrium — a structure rooted in ancient Roman design and revived in modern multi-story buildings as a glass-roofed space for daylighting and natural ventilation. Atriums depend on two fundamental natural phenomena, the greenhouse effect and the chimney effect, and analyzing the external airflow around them is the first step toward designing them effectively.In this simulation, an 8 m/s horizontal wind is driven across the atrium walls, producing the full range of external-flow behavior seen around bluff bodies: high-pressure stagnation zones, flow separation, recirculation, and local acceleration. At the urban scale, this matters because the wind around large buildings governs pedestrian comfort, natural ventilation performance, and how a structure interacts with its surrounding built environment — all central concerns of façade design, wind loading, and urban planning. By the end, you gain a reusable external-flow workflow that transfers to virtually any building-aerodynamics problem.MethodologyThe 3D external-flow domain (3.35 m × 2.21 m × 3.9 m) is constructed around the atrium in Design Modeler, sized to capture the wake and pressure field without artificially constraining the flow. The geometry is discretized into a refined unstructured mesh of roughly 1.95 million elements, with cell refinement concentrated near the building walls to resolve the boundary layer accurately.On the solver side, a pressure-based, steady-state solver is selected — the natural choice for incompressible external aerodynamics. Turbulence is modeled with the RNG k-ε model together with standard wall functions, a combination well suited to the separated and recirculating flows that form around bluff bodies. Boundary conditions follow the standard external-flow setup: an 8 m/s velocity inlet, a 0 Pa gauge-pressure outlet, and stationary walls. Pressure-velocity coupling uses the SIMPLE scheme, with second-order discretization applied to pressure and momentum for improved accuracy. The domain is initialized with atmospheric pressure (101,325 Pa) and a uniform freestream velocity.AnalysisPost-processing translates the converged solution into a clear physical picture of the flow. The results are presented as 2D and 3D contours of pressure and velocity, pathlines tracing the flow around and behind the structure, and velocity vectors on the XY plane that reveal separation and recirculation zones in detail. The pressure distribution over the building's wall surfaces is extracted directly, showing where the wind loads the structure most heavily and how the pressure field organizes around it.Together these results let you identify stagnation, separation, recirculation, and acceleration regions and connect them back to real engineering decisions — façade design, pedestrian wind comfort, natural-ventilation potential, and structural wind loading.

DescriptionThis project models the external airflow around a building atrium using ANSYS Fluent. Atriums—rooted in Roman architecture and now often multi-story with glazed roofs—rely on the greenhouse and chimney effects for daylight and natural ventilation, and analyzing the wind around them is the first step in designing them well. Here, an 8 m/s horizontal wind flows across the atrium walls, generating high-pressure, separation, recirculation, and acceleration zones typical of bluff-body flow.MethodologyThe 3D external-flow domain (3.35 m × 2.21 m × 3.9 m) is built around the structure in Design Modeler. Meshing produces an unstructured grid of ~1,950,000 elements, locally refined near the building walls to resolve the boundary layer. A pressure-based, steady-state solver is used with the RNG k-ε model and standard wall functions; boundary conditions are an 8 m/s velocity inlet, a 0 Pa gauge-pressure outlet, and stationary walls, with SIMPLE coupling and second-order pressure and momentum discretization.ConclusionThe simulation examines pressure and velocity distributions and the overall airflow behavior around the atrium. Outputs include 2D/3D contours of pressure and velocity, pathlines, and velocity vectors on the XY plane, along with the pressure distribution over the wall surfaces—enabling identification of stagnation, separation, and recirculation zones relevant to façade design, wind comfort, and structural wind loading.

DescriptionThis project simulates the airflow inside a building's double-skin façade (DSF) using ANSYS Fluent. In a DSF, solar-heated air rises by buoyancy through a ventilated cavity, providing passive heating while assisting ventilation and cooling within the building. The 3D geometry, built in Design Modeler, is a rectangular cavity of 0.6 × 3.2 × 5 m, made up of an airflow duct and a glazed section that absorbs solar heat. It has a 0.2 m rectangular inlet at the base of the glass wall and a 0.2 m outlet near the top. Meshing in ANSYS Meshing produces 490,725 elements.MethodologyThe study evaluates the buoyancy-driven circulation set up inside the DSF cavity. Solar gain on the glazing is represented by a volumetric heat generation of 6,940 W/m³ applied to the glass section. The building walls are brick and lose heat by free convection to the interior, modeled with T = 300 K and h = 23 W/m²·K. Supply air enters the façade at 304.55 K and atmospheric pressure. To capture buoyancy, air density follows the ideal-gas law and gravity is set to 9.81 m/s².AnalysisPost-processing delivers 2D and 3D contours of pressure, velocity, and temperature, along with 2D and 3D velocity vectors. The vectors show a clear upward flow through the cavity, confirming the buoyancy-driven ventilation that characterizes a double-skin façade.

DescriptionThis project simulates the airflow through the gap between the two walls of a building's double façade using ANSYS Fluent, under steady-state, pressure-based conditions with gravity included. The 3D geometry, created in Design Modeler, is a rectangular chamber of 3 × 1.5 × 0.2 m fitted with 120 rows of thin shading plates angled at 45 degrees in a shutter-like arrangement. These plates, positioned between the two façade walls, are the key element driving ventilation within the cavity. The model is meshed in ANSYS Meshing with an unstructured grid of 4,264,442 elements. The goal of the study is to characterize the upward airflow and heat transfer that develop in the space between the two shells and around the shading plates.MethodologyThe energy equation is enabled to resolve the temperature distribution, and turbulence is modeled with the standard k-ε model. Atmospheric pressure boundary conditions are applied at both the inlet and outlet of the cavity, allowing buoyancy-driven upward flow to develop naturally from the density variations produced by pressure and temperature changes. Since solar heating of the shading plates is the primary driver of these temperature changes, the Discrete Ordinates (DO) radiation model is used together with the solar ray-tracing model. The surrounding ambient air is taken at 300 K with a heat transfer coefficient of 10 W/m²·K.AnalysisPost-processing produces 2D and 3D contours of pressure, velocity, and temperature, along with 2D and 3D pathlines. The 2D contours are presented on the XY plane at the mid-section of the cavity between the two façade walls. Velocity is also plotted along a line in the XZ plane at a height of 2 m from the floor, running through the geometric center between x = −0.1 and x = +0.1, consistent with the 45-degree orientation of the shading plates. The results reveal the upward, buoyancy-driven flow and the heat transfer around the shutter plates within the double-façade cavity.

DescriptionA windcatcher is a tall rooftop tower used for passive, energy-free ventilation — a centuries-old design still relevant in sustainable architecture. It captures ambient wind at roof level and channels it down into the building below, flushing out warm, stale indoor air and replacing it with fresh outside air. Internal walls and channels trap the incoming flow and guide it downward from the upper intake panels into the occupied space. This project uses ANSYS Fluent to simulate the airflow through an octagonal windcatcher and confirm that it ventilates the room beneath as intended. The windcatcher sits inside a large open-domain environment with a horizontal wind of 10 m/s at atmospheric pressure. The geometry is built in Design Modeler and meshed in ANSYS Meshing with an unstructured grid of about 2.33 million cells.MethodologyThis is a fluid-only analysis with no heat transfer, so the focus is purely on how the tower's geometry drives air movement. The key feature is the internal layout above the windcatcher: barrier surfaces are arranged so that some upper inlets face the wind directly while others are shielded from it. This sets up a pressure difference across the tower — the windward openings push air in, while the leeward openings generate suction — and that differential is what drives circulation down through the windcatcher shaft and into the room below.AnalysisPost-processing generates velocity and pressure contours along with velocity vectors and pathlines. The windward side shows higher pressure than the leeward side, exactly as the design relies on. The flow visualizations confirm the intended behavior: air enters through the top panels, is guided and trapped by the interior walls, then descends and discharges through the lower panels into the interior space — showing the windcatcher works as designed. By the end of this project, you'll be able to set up an external-flow ventilation simulation in a large open domain, use barrier surfaces to create a driving pressure differential, and interpret pressure and flow fields to verify that a passive ventilation system performs as intended.

DescriptionThis project uses ANSYS Fluent to simulate a wind tower system paired with a qanat, a traditional passive cooling arrangement rooted in the architecture of hot, arid regions. Passive ventilation techniques rely entirely on natural driving forces rather than mechanical equipment, and they generally fall into two categories: wind-driven systems, where airflow is generated by pressure differences, and buoyancy-driven systems, where temperature-induced density differences create natural convection. The wind tower and qanat combination sits in a hybrid category, drawing on both mechanisms at once.In this setup, a tall tower rises above the building and works together with an underground channel — the qanat — which acts as a natural cooling reservoir. When wind strikes the tall structure, it creates a pressure imbalance: high pressure builds on the windward face while a low-pressure zone forms behind it, driving suction that pulls air through the system. Meanwhile, inside the underground channel, incoming hot air passes over a body of cool water, picking up moisture and losing heat before rising into the building through the floor to condition the interior air.To keep the model manageable, the water surface inside the channel wasn't explicitly represented; instead, a fixed-temperature boundary condition of 278 K was applied to the channel walls to represent its cooling effect. The incoming hot air enters the channel at 0.2 m/s and 300 K. Window surfaces exposed to sunlight and outdoor heat were assigned a constant temperature of 298 K. The geometry, built in Design Modeler, consists of three connected components: the room, the tower, and the underground channel. Meshing was carried out in ANSYS Meshing using an unstructured approach, producing 402,198 cells.MethodologyThe simulation was run as a steady-state, time-independent case using a pressure-based solver in ANSYS Fluent. Because natural convection plays a central role here, buoyancy effects were captured by allowing air density to vary with temperature rather than treating it as constant — warmer, lighter air rises, which is what drives hot air out through the tower. This density variation was modeled using the incompressible ideal gas law, where density depends on temperature and operating pressure rather than on local pressure fluctuations, consistent with the assumption of constant pressure throughout the domain.ConclusionThe simulation produced temperature, pressure, and velocity contours in both 2D and 3D, along with velocity vector fields. The temperature results clearly show the cooling pathway: cool air drawn in through the underground channel and hot air escaping through the tower opening. The pressure field confirms the mechanism driving this exchange, with high pressure outside and lower pressure inside the room and tower pulling hot air upward and out. The velocity vectors trace this circulation clearly, showing cool air entering rapidly at floor level, circulating through the room, and exiting through the tower once conditioning is complete. Overall, the results confirm that this passive wind tower and qanat system successfully performs natural air conditioning without any mechanical input.

DescriptionThis project simulates the HVAC performance of a room fitted with a solar chimney using ANSYS Fluent. The model consists of two main parts: the interior of the room and a sloping solar chimney mounted on the room's ceiling. As a passive, sun-driven ventilation device integrated into the building envelope, the solar chimney is a natural subject for architectural engineering, where the goal is to improve indoor comfort and air quality through the building's own design rather than mechanical systems.The solar chimney has glass plates on its side surfaces that are in contact with the outdoor environment. As a transparent medium, the glass admits solar energy, while a plate at the back of the chimney acts as a heat-absorbing surface. The absorbing surface behind the chimney is assumed to be held at a constant temperature of 335.15 K. The glass surface exposed to the outdoor environment, in contrast, exchanges heat with its surroundings by convection: the ambient air temperature is 308.15 K, and the convective heat transfer coefficient is 8 W/m²K. In addition, the solar energy absorbed inside the chimney is represented as a constant volumetric heat source of 15,000 W/m³.MethodologyThe 2D geometry was created in Design Modeler and comprises two parts: a room measuring 2 m × 3 m, and a solar chimney 2 m long, inclined at 45 degrees to the room's ceiling, with a width of 0.15 m. Meshing was performed in ANSYS Meshing using a structured grid of 42,846 elements.The airflow enters through the inlet at the bottom of the room under a pressure-inlet boundary condition. Air at 308.15 K is drawn into the room by the heat generated within the solar chimney and then carried out to the external environment, establishing a continuous, buoyancy-driven ventilation path through the space.ConclusionOn completion of the solution, two-dimensional contours of pressure, temperature, and velocity were obtained, along with pathlines and velocity vectors.In addition, the temperature distribution across the chimney was plotted at a point midway along its length (1 m from the inlet and outlet), together with the velocity variation across the chimney outlet section. The transverse temperature profile at a point 1 m from the chimney inlet, over the 0.15 m thickness, was extracted and compared against the corresponding temperature profile reported in a reference paper, providing validation of the simulation.As the results demonstrate, the heat of the solar chimney successfully induces natural airflow that ventilates the room passively — drawing fresh air in at the base and expelling it through the inclined chimney — illustrating how a solar chimney can be integrated into an architectural design to enhance indoor ventilation with minimal energy input.

DescriptionThis project uses ANSYS Fluent to study how airborne dust particles enter a room through its windows and then travel and deposit inside — a problem central to indoor air quality, occupant health, and the accumulation of sediment on interior surfaces. Outdoor air carrying a dust load infiltrates the space and disperses, with some particles following the main airflow and others settling out where the flow slows or recirculates. The 3D geometry, built in Design Modeler, represents a room fitted with two windows and a chimney, which together define the inlet and outlet paths for the air. Meshing in ANSYS Meshing yields 42,061 elements. Because deposition builds up over time rather than instantaneously, the simulation is run as a transient analysis.MethodologyDust-laden air enters through the two window inlets at 0.25 m/s and exits through a pressure outlet at the top of the chimney, establishing the through-flow that transports the particles across the room. The continuous air phase is treated with the laminar flow model, appropriate for the low inlet velocity. Particle transport and settling are modeled with a two-way coupled Discrete Phase Model (DPM), so that momentum is exchanged in both directions between the dust and the carrier air rather than the particles simply following the flow passively. This coupling captures how the particles are carried, slowed, and ultimately deposited as the airflow evolves in time.AnalysisPost-processing provides 2D velocity contours, velocity vectors, and streamlines that reveal both the airflow paths through the room and the motion of the dust within them. The wind-driven flow carries particles along the main stream from the windows toward the chimney, while the recirculation zones that form away from the primary path trap particles and promote enhanced deposition and sediment accumulation. Together these results show where dust is most likely to settle inside the room and how the window-to-chimney flow governs its distribution.

DescriptionThis case study uses ANSYS Fluent to model wind flow around a cluster of three buildings, a canonical bluff-body aerodynamics problem central to architectural and structural wind engineering. Understanding how wind interacts with building masses is essential for façade load design, pedestrian wind comfort assessments, and site planning around tall structures. A 5 m/s horizontal airstream is directed at the building group to study wake formation and vortex shedding behavior downstream.MethodologyThe simulation is transient, run for 1 s with a 0.01 s time step, using a pressure-based solver. The computational domain, built in DesignModeler, is a 120 m × 300 m × 100 m rectangular volume containing three 75 m tall buildings — representative of a mid-to-high-rise urban block. The domain was meshed in ANSYS Meshing using an unstructured grid of 128,893 elements, with local refinement around the building surfaces to resolve near-wall flow gradients and boundary layer effects accurately.ConclusionOutput includes pressure and velocity contours, turbulent kinetic energy (TKE), pathlines, and velocity vector fields, all evaluated at the final time step (t = 1 s). Peak pressure occurs on the windward façades, where incoming flow first impinges — directly relevant to cladding and structural load estimation in building design. Leeward wakes show clear vortex formation, illustrating the kind of turbulent recirculation zones that inform pedestrian-level wind comfort and building-spacing decisions in architectural planning.

DescriptionThis project applies computational fluid dynamics to study how carbon dioxide from vehicle exhaust disperses through an urban street canyon, a question that matters increasingly for urban planning as air quality pressures mount in fast-growing cities. Built in ANSYS Fluent, the simulation models a three-dimensional block of city buildings framing a street, contained in a 9 m × 13 m × 4 m domain. Traffic emissions are represented as a continuous 0.1 m-high source strip running along the street, generating CO2 at 4 kg·m⁻³. Ambient air enters through three sides of the domain at 0.2 m/s and 300 K, allowing the surrounding wind field to carry the pollutant away from its source and through the canyon.MethodologyBecause the flow involves two distinct gas species, air and CO2, the Species Transport model is used to solve separate transport equations for each, with the energy equation active to capture thermal effects on the mixture. Turbulence is closed with the standard k–ε model and standard wall functions, and the equations are solved transiently with a pressure-based solver, so the concentration field can be tracked as it evolves over time rather than only at steady state. The domain is meshed with roughly 4.14 million unstructured elements, with local refinement near solid boundaries to resolve the sharp concentration gradients expected close to the source and building walls.AnalysisResults are reported as 2D and 3D contours of pressure, temperature, velocity, and species mass fraction, with the region around the emission source examined most closely to show how incoming airflow dilutes and redistributes the CO2 across the canyon. These fields point to concrete conclusions for urban planning: they identify pockets of stagnation and accumulation that should steer where pedestrian zones, entrances, and street-level activity are placed; they illustrate how street orientation, building height, and block spacing govern natural ventilation, giving planners a physical basis for these design choices; and, more broadly, they establish a workflow that can be reused to screen the ventilation performance of proposed developments before construction, comparing candidate urban layouts on their ability to clear traffic-derived pollutants.