Falling Droplet — ANSYS Fluent CFD SimulationDescriptionWelcome to the Falling Droplet CFD Simulation module. This project introduces the behavior of a falling water droplet in air, using the Volume of Fluid (VOF) method in ANSYS Fluent. A single droplet falling through air is the most basic air–water interface problem there is, making it a perfect first case for multiphase flow — the droplet deforms, oscillates, and may even break up as surface tension, gravity, and air resistance act on it. Droplet dynamics of this kind underlie spray systems, inkjet printing, rainfall analysis, and atomization. As the opening project of the Multiphase Flow: Beginner CFD Training Package, it introduces the VOF method — the sharp-interface free-surface model — on the simplest possible geometry, establishing the foundation for the cases that follow.MethodologyThe simulation uses a pre-configured axisymmetric geometry representing the droplet and the surrounding air domain, with a mesh designed to capture the droplet interface and its deformation precisely. The initial droplet parameters — size, shape, and initial velocity — are configured at the start, and the surrounding air domain is defined with appropriate boundary conditions. The VOF model lies at the heart of the setup: an optimal VOF scheme is selected for stable, accurate tracking of the water–air interface as the droplet falls, and the crucial physical effects of surface tension and gravity are incorporated, since these are what govern the droplet's shape and stability. The case is solved transient to capture the time-dependent evolution of the droplet.AnalysisPost-processing focuses on the droplet's shape evolution through time-dependent contours and animations that reveal its deformation and oscillation, with deformation metrics such as aspect ratio and oscillation frequency quantified during the fall. The results allow you to investigate how surface tension affects the droplet's ability to hold its shape or break up, and how air resistance influences its motion and terminal velocity, while the transient time-series data track the evolution of the droplet's properties and pinpoint critical stages such as potential breakup. These insights connect directly to optimizing spray and atomization systems and to improving rainfall and cloud-formation models in atmospheric science. By the end of this project, you'll be able to set up a transient VOF simulation of a falling droplet, incorporate surface tension and gravity, track the liquid–gas interface accurately, and interpret the droplet's deformation, oscillation, and stability.

Pouring Water Out of a Bottle — ANSYS Fluent CFD SimulationThis project simulates water pouring out of a bottle using ANSYS Fluent. The two-phase flow field is modeled using the Eulerian multiphase approach, which allows multiple distinct but interacting phases—liquid, gas, or solid, in nearly any combination—to be solved simultaneously.Geometry and MeshThe 2-D geometry was created in SpaceClaim and meshed in ANSYS Meshing using an unstructured mesh across the entire domain, totaling 150,642 elements.Setup and AssumptionsGiven the incompressible nature of the flow, a pressure-based solver is used, with the simulation run as transient and gravity set to -9.81 m/s² along the Y-axis.The multiphase model is set to Eulerian with the Multi-Fluid VOF formulation, involving two phases—air as the primary phase and water as the secondary phase—using sharp interface modeling and explicit formulation. Turbulence is handled with the standard k-epsilon model and standard wall functions.Air is defined with a density of 1.225 kg/m³ and viscosity of 1.7894×10⁻⁵ kg/m·s, while water-liquid has a density of 998.2 kg/m³ and viscosity of 0.001003 kg/m·s. A pressure outlet boundary condition is applied at the outlet.The SIMPLE scheme is used for pressure-velocity coupling, with PRESTO! for pressure and second-order upwind discretization for momentum, turbulent kinetic energy, and turbulent dissipation rate. The volume fraction is solved using a compressive scheme. The domain is initialized using the hybrid method, with the water region patched to a volume fraction of 1.The simulation runs with a time step size of 0.0025 s, a maximum of 20 iterations per time step, and a total of 3,708 time steps.ResultsUpon completion, contours of water velocity, pressure, water volume fraction, and eddy viscosity are extracted. The results show that, under the influence of gravity, water flows out of the bottle and discharges into an adjacent empty container, gradually filling it.

Fountain Waterfall — ANSYS Fluent CFD SimulationDescriptionThis project presents a numerical simulation of a fountain waterfall using ANSYS Fluent, with multiphase flow as the central theme. The system involves two fluids — water as the primary working fluid and air as the secondary phase — and the heart of the study is capturing how these two phases interact as the fountain fills and spills. To do this, the Eulerian multiphase model is used, treating water and air as interpenetrating phases each with its own set of governing equations. Water enters the fountain at 1 m/s, and gravity is included at −9.81 m/s² along the y-axis, since the rise and fall of the water under gravity is exactly what the simulation sets out to reproduce. Within the Multiphase Flow: Beginner CFD Training Package, this project models a fountain's filling and overflow with the Eulerian multiphase model, capturing the coupled motion of water and air under gravity.MethodologyThe three-dimensional geometry was created in Design Modeler and consists of a fountain with a single inlet set within a surrounding cylindrical ground domain. The base of the cylinder is treated as the ground, while the remaining surfaces are pressure outlets. Meshing was performed in ANSYS Meshing using an unstructured grid with no element quality below 0.64, ensuring a reliable representation of the flow. The simulation uses a pressure-based, transient solver, appropriate for following the time-dependent filling and spilling of the fountain. Only the fluid behavior is examined here — heat transfer is not modeled — and gravity acts along the y-axis. Turbulence is represented with the standard k-ω model including shear-flow corrections. Within the multiphase setup, air is defined as the primary phase and water as the secondary phase using an explicit formulation, which sharply resolves the evolving water–air interface. At the inlet, water enters at 1 m/s with a volume fraction of unity; at the outlets, the backflow volume fraction is set to air, so that any returning flow is treated as air rather than water. Phase-coupled pressure–velocity coupling is used together with the PRESTO! pressure scheme and first-order upwind discretization for momentum, specific dissipation rate, and volume fraction.AnalysisThe solution yields two- and three-dimensional fields of velocity and of the water and air volume fractions, together with an animation of the fountain filling. Starting from an inlet velocity of 1 m/s, the fountain takes about 1.8 s to fill, after which it begins to spill over and the simulation ends. The results reveal a clear relationship between the inlet velocity and diameter and both the time required to fill the fountain and the resulting wetted area. By the end of this project, you'll be able to set up a transient Eulerian multiphase simulation, define primary and secondary phases with an explicit formulation, apply phase-coupled coupling with appropriate boundary conditions, and interpret the velocity and volume-fraction fields that capture a fountain's filling and overflow under gravity.

Waterfall (Two-Phase Flow) — ANSYS Fluent CFD SimulationDescriptionWelcome to the Waterfall Two-Phase Flow CFD Simulation module. This project introduces waterfall hydraulics through computational fluid dynamics, showing how ANSYS Fluent can simulate and analyze the complex behavior of a waterfall. Because a waterfall involves both water and air moving together with a constantly changing interface between them, it is a natural introduction to multiphase flow modeling — a skill central to hydraulic structure design and water resource management. Waterfalls matter across civil engineering, from landscape design and stormwater management to energy dissipation in structures such as dam spillways, and modeling them accurately means capturing free-fall conditions and air entrainment. Within the Multiphase Flow: Beginner CFD Training Package, this project applies the two-phase free-surface approach to a gravity-driven waterfall, building on the earlier free-surface cases.MethodologyThe workflow begins with defining an appropriate geometry and mesh for the waterfall configuration, then configuring the two-phase flow properties of water and air. Realistic boundary conditions are set up — specifying inlet flow rates and outlet conditions, and implementing free-surface, air-interface, and solid-wall boundaries so that the flow is captured faithfully. Handling the two phases correctly is the heart of the setup, since it is the interaction between the falling water and the surrounding air that defines a waterfall. The solver is then configured with time-stepping and convergence criteria suited to this kind of flow, and the solution is monitored throughout for stability and to identify potential issues as they arise.AnalysisPost-processing visualizes the water flow patterns through velocity fields and streamlines, analyzes the velocity distributions and air entrainment that determine a waterfall's performance and downstream impact, and studies the free surface — the dynamic interface between water and air — to understand how it forms and evolves. These insights connect directly to real hydraulic engineering practice, showing how the observed flow patterns and velocity distributions can inform waterfall design and performance assessment, while also making clear the simplifications inherent in an introductory model. By the end of this project, you'll be able to set up and run a basic two-phase waterfall simulation in ANSYS Fluent, capture the free surface and air entrainment under free-fall conditions, interpret the velocity and flow-pattern results, and apply those insights to hydraulic-structure and water-feature design.

DescriptionOpen-channel flow over rough riverbeds is a core application of multi-phase flow modeling in Fluent, where the water-air interface must be resolved alongside the effects of bed roughness on velocity and flow behavior. This CFD study uses ANSYS Fluent to simulate open-channel two-phase flow in natural river systems, examining how bed roughness influences flow characteristics relevant to water resource management and flood control.MethodologyThe channel geometry is built with a rough bed representation, and appropriate meshing strategies are applied to resolve flow near the bed surface. Two-phase flow properties are configured to define the water and air phases within the domain, with free surface modeling used to capture the dynamic interface between the two. Bed roughness is incorporated through surface roughness parameters and geometric representations, configured to capture its influence on velocity profiles and overall flow behavior. Boundary conditions are set at the inlet and outlet to represent realistic river flow scenarios, with appropriate conditions defined for the free surface, channel walls, and bed. Solver parameters, including time-stepping and convergence criteria, are configured for the open-channel flow simulation, with progress monitored throughout the solving process to ensure stability.Results AnalysisPost-processing generates visualizations of velocity fields and streamlines to characterize water flow patterns within the rough channel, along with velocity profiles and water surface behavior relevant to assessing river flow characteristics. Free surface behavior is examined to capture the water-air interface dynamics throughout the channel. These results provide insight into how bed roughness and channel geometry shape open-channel flow, supporting applications in river training works, flood prediction, and erosion control strategies within civil and hydraulic engineering practice.

Multi-Phase Flow in an Injector (Two-Phase VOF Model) — ANSYS Fluent CFD SimulationDescriptionWelcome to the Injector CFD Simulation module. This project introduces multiphase flow analysis within a fuel injector — a critical component across combustion systems in automotive, aerospace, and energy applications — using the Volume of Fluid (VOF) multiphase model in ANSYS Fluent. Inside an injector, liquid fuel and the surrounding gas meet and interact within confined, narrow internal passages, and capturing that dynamic liquid–gas interface is the core of the problem. Injector simulations of this kind support automotive fuel systems, aerospace propulsion, and industrial combustion. Within the Multiphase Flow: Beginner CFD Training Package, this project applies the VOF model to a real device, moving from free-surface flows to two-phase flow inside a confined injector geometry.MethodologyThe project uses a pre-configured injector model, examining the key geometric features of a realistic injector design along with the mesh characteristics needed to resolve the liquid–gas interface within its narrow internal passages. Realistic operating conditions are defined, including appropriate pressure, velocity, and fluid-property settings at the fuel inlet, along with proper representation of the surrounding gas phase and the wall boundaries. The VOF model is central to the setup: the VOF scheme is selected and configured for stable, accurate interface capture within the injector's complex internal geometry, and surface tension and turbulence effects are incorporated, since these govern the fluid behavior during injection. The case is solved as a steady-state simulation.AnalysisPost-processing interprets the multiphase flow behavior through contours and animations showing the spatial distribution of liquid fuel and gas, alongside quantitative assessment of velocity profiles, pressure distributions, and spray characteristics at the nozzle exit. From these results you can examine how the injection pressure influences the flow behavior and phase distribution, how the nozzle geometry could be optimized to improve atomization and spray quality, and how to evaluate injector efficiency, flow uniformity, and potential cavitation risk. These insights connect directly to optimizing fuel-injection systems for better engine performance and cleaner, more efficient combustion. By the end of this project, you'll be able to set up an injector simulation with the VOF two-phase model, configure interface tracking with surface tension and turbulence in a confined geometry, and interpret the volume-fraction, velocity, and pressure results that characterize liquid–gas interaction in a high-pressure injection system.

Fuel Injector, Three-Phase Flow (Mixture Model) — ANSYS Fluent CFD SimulationDescriptionWelcome to the Fuel Injector Three-Phase Flow CFD Simulation module. This project introduces fuel injection systems — a critical component in automotive and aerospace engineering — using the Mixture multiphase model in ANSYS Fluent to simulate three-phase flow inside an injector. Where the earlier injector case handled two phases, this one adds a third: liquid fuel, air, and fuel vapor all interact within the high-pressure injector, and the Mixture model represents their phase interactions, slip velocities, and mass transfer. Three-phase injector modeling of this kind supports automotive engines, aerospace propulsion, and combustion engineering. Within the Multiphase Flow: Beginner CFD Training Package, this project introduces the Mixture model and steps up to three phases, building on the two-phase VOF injector case.MethodologyThe project uses a pre-configured fuel injector geometry representing a real-world injector, including its internal passages and nozzle design, with a mesh built to capture the phase coupling within the complex geometry. Realistic boundary conditions are defined: flow rates, pressures, and phase fractions at the fuel inlet and air intake, along with nozzle-outlet and ambient conditions for spray formation. The Mixture model is central to the setup — the slip-velocity and mass-transfer models are selected and configured for accurate liquid–gas–vapor interaction and fuel vaporization, and turbulence and cavitation effects are incorporated, since these govern the multiphase behavior in the injector. The case is solved as a steady-state simulation.AnalysisPost-processing visualizes the phase distribution and velocity profiles through contours and vector plots that reveal how liquid fuel, air, and fuel vapor move through the injector and nozzle, with spray characteristics such as cone angle, droplet size distribution, and vapor concentration quantified in the near-nozzle region. From these results you can investigate how injection pressure affects spray atomization, how nozzle geometry influences the flow patterns, and how effectively fuel and air mix — identifying opportunities to optimize the injector design. These insights connect directly to improving engine efficiency, reducing emissions, and enhancing combustion stability through precise fuel delivery. By the end of this project, you'll be able to set up a three-phase injector simulation with the Mixture multiphase model, configure slip-velocity, mass-transfer, and cavitation effects, and interpret the phase-distribution, velocity, and spray results that characterize fuel injection.

Gas Sweetening System Hydrodynamic AnalysisDescriptionThis project presents a computational fluid dynamics study of the hydrodynamic behavior inside a gas sweetening facility using ANSYS Fluent software. Gas sweetening is a critical industrial process used to remove hydrogen sulfide, carbon dioxide, mercaptans, and other contaminants from natural gas and synthetic gas streams, ensuring safe transportation and end use. Treating sour gas is essential because of the strongly corrosive effect of hydrogen sulfide and carbon dioxide on pipeline infrastructure, as well as their toxic effects on human health.The computational domain involves two distinct materials: a specific sour gas composition and an amine solution stream. This study focuses exclusively on the hydrodynamic aspects of the process and does not model the actual gas removal mechanisms, which typically involve complex physical or chemical interactions. For this hydrodynamic analysis, water is used as a substitute for the amine. A Volume of Fluid (VOF) multiphase model is used to define the two-phase environment. The system features two separate inlets for the amine and gas streams, with the amine flow entering at a velocity of 0.3 m/s before meeting the gas stream inside the processing equipment.The gas sweetening equipment is modeled in three dimensions using Design Modeler software, with realistic inlet configurations for the introduction of both the gas and amine streams into the vessel. The meshing is performed using ANSYS Meshing software, generating an unstructured mesh of 2,168,649 elements. This mesh density provides sufficient resolution to capture the complex multiphase flow interactions within the equipment.MethodologySeveral assumptions are applied in this simulation. A pressure-based solver is used for the incompressible flow analysis, and the simulation is run as a steady-state case. The effect of gravity is taken into account, with a gravitational acceleration of -9.81 m/s² applied along the vertical direction.For the turbulence modeling, the RNG k-epsilon model with the standard wall function is used. The two-phase flow is captured using the VOF model with two Eulerian phases (gas and water) and a dispersed interface modeling approach.Regarding the boundary conditions, the gas inlet is defined as a velocity inlet with a velocity of 0 m/s and a water volume fraction of 0, while the amine inlet is defined as a velocity inlet with a velocity of 0.3 m/s and a water volume fraction of 1.0. Both the gas outlet and the amine outlet are defined as pressure outlets with a gauge pressure of 0 Pa, and the equipment walls are treated as stationary walls with a no-slip condition.In terms of the solution methods, the pressure–velocity coupling is handled with the SIMPLE algorithm. The PRESTO! scheme is used for pressure, second-order upwind for momentum, and first-order upwind for both the turbulence parameters and the volume fraction. The solution is initialized using the standard method, with zero gauge pressure, zero velocity components, and a zero water volume fraction throughout the computational domain.ConclusionAfter the solution, two- and three-dimensional contours of pressure, velocity, and the phase volume fractions for both the gas and water phases are obtained. The results show that the gas and amine streams collide after passing through the internal flow barriers within the processing equipment.This collision demonstrates the ability of the amine stream to redirect part of the gas flow toward the equipment outlet. This behavior provides a basis for understanding the mixing and contact efficiency in real gas sweetening operations, where chemical absorption would take place between the amine solution and the acid gas components. The velocity and pressure contours offer valuable insight into the flow distribution patterns, mixing zones, and potential areas for equipment optimization, all of which are essential for designing efficient gas–liquid contact systems in industrial sweetening applications.

DescriptionThis project simulates Eulerian two-phase flow in a moving-wall cylinder using ANSYS Fluent, investigated through CFD analysis. The system consists of two fluids: water as the primary fluid, together with a secondary fluid (with a density of 2610 kg/m³ and a viscosity of 0.0026 kg/m·s).The two-phase flow enters the chamber in the shape of a hollow cylinder. Water enters the system at a velocity of 0.629 m/s with a volume fraction of 0.67, while the secondary fluid enters at 0.099 m/s with a volume fraction of 0.23, under a relative pressure of 1,379,000 Pa.The 3D geometry was created in Design Modeler. It consists of two concentric cylinders — an outer and an inner cylinder — with the two-phase fluid flowing through the annular space between the outer and inner walls; the inlet and outlet take the form of hollow circles. Meshing was performed in ANSYS Meshing using an unstructured grid, producing 11,880 elements.MethodologyThe Eulerian multiphase model is used to represent the flow of the two fluids through the system, treating each phase as an interpenetrating continuum with its own set of governing equations. The outer wall of the cylinder is stationary, while the inner wall is a moving wall rotating about the central axis of the cylinder at 30 rpm.The model employs the standard k-omega turbulence model with the shear-flow correction option, together with the dispersed turbulence model for the multiphase flow.ConclusionThis study investigates the effect of the rotating inner wall on the Eulerian multiphase turbulent flow.On completion of the solution, two- and three-dimensional contours were obtained for pressure (for the mixture), velocity (for both the water phase and the secondary-fluid phase), the volume fraction of water and of the secondary fluid, and the path lines of each phase.The two-dimensional contours are presented in two planes: the YZ section and the XY section. The YZ section is defined along the central axis of the cylinder, while the XY section is taken perpendicular to the central axis at distances of 4, 9, and 13.716 m (the outlet) from the inlet — allowing the development of the two-phase flow to be tracked along the length of the cylinder.

Eulerian Two-Phase Flow within a Convergent-Divergent Channel — ANSYS Fluent CFD SimulationDescriptionWelcome to the Eulerian Two-Phase Flow within a Convergent-Divergent Channel CFD Simulation module. This project introduces fluid-fluid interactions in geometrically complex systems using the Eulerian multiphase model in ANSYS Fluent. A convergent-divergent channel changes cross-section along its length, so the two phases accelerate, decelerate, and redistribute as the area varies — a rich test of how the Eulerian model handles phase interactions and momentum transfer under changing flow conditions. The Eulerian model is the most detailed multiphase formulation, solving each phase separately, and applications range from nozzles and diffusers to heat exchangers and reactors. As the capstone of the Multiphase Flow: Beginner CFD Training Package, this project introduces the Eulerian model — the most advanced of the three multiphase approaches — in a geometrically demanding channel.MethodologyThe project uses a pre-configured convergent-divergent channel geometry representing a real flow system with varying cross-sectional areas, with a mesh built to capture the phase coupling within the complex geometry. Realistic boundary conditions are defined — flow rates, velocities, and phase fractions at the inlets and outlets, along with wall boundary conditions and roughness effects. The Eulerian model is central to the setup: the interfacial drag and lift models are selected and configured for the immiscible fluids, and turbulence modulation and phase-coupling effects are incorporated to govern the momentum exchange between phases. The case is solved as a steady-state simulation.AnalysisPost-processing visualizes the phase fractions and velocity profiles through contours and vector plots along the channel, revealing how both phases move through the converging and diverging sections, with pressure drops and phase-separation tendencies quantified along the way. From these results you can investigate how the area changes affect the phase distribution and velocities, how the convergent-divergent angle influences flow patterns and separation, and where flow-regime transitions and critical zones for optimization occur. These insights connect directly to optimizing multiphase systems in complex geometries and enhancing heat transfer in two-phase equipment. By the end of this project, you'll be able to set up a two-phase Eulerian simulation in a variable-area geometry, configure interfacial drag, lift, and turbulence-modulation models, and interpret the phase-fraction, velocity, and pressure results that characterize Eulerian two-phase flow through a convergent-divergent channel.