Waterfall Using Two-Phase Flow — ANSYS Fluent CFD SimulationDescriptionWelcome to the Waterfall using Two-Phase Flow CFD Simulation module. This project introduces civil and hydraulic engineers to the world of waterfall hydraulics using ANSYS Fluent. A waterfall is one of the most intuitive free-surface flows: water falls freely through air, entraining bubbles and dissipating energy as it lands. Beyond their natural appeal, waterfalls play a real engineering role in landscape design, stormwater management, and energy dissipation in structures such as dam spillways. Modeling one well means capturing free-fall conditions and air entrainment at the dynamic interface between water and air. As the opening project of the Hydraulic & Civil: Beginner CFD Training Package, it introduces the core tool used throughout the package — the two-phase Volume of Fluid (VOF) method for tracking the water–air interface — through the simplest and most approachable free-surface case.MethodologyThe workflow begins with creating a basic geometry representing a waterfall configuration and applying an appropriate meshing strategy for accurate flow analysis. The two-phase flow is then set up by defining the properties of water and air within ANSYS Fluent. The boundary conditions are central to a realistic result: inlet flow rates and outlet conditions are specified to represent the waterfall scenario, while free-surface and wall boundary conditions capture the water surface, the air interface, and the solid boundaries. The solver parameters — including time-stepping and convergence criteria — are configured to suit a free-surface hydraulic simulation, and the solution is monitored for stability and convergence throughout.AnalysisPost-processing focuses on extracting meaningful insight from the flow. Velocity fields and streamlines are visualized to understand the flow behavior through the waterfall, while velocity profiles and air-entrainment patterns are examined to assess performance and downstream impact. Free-surface visualization reveals the dynamic water–air interface at the heart of the problem. 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 flow patterns and air entrainment in free-fall conditions, interpret the free surface and velocity results, and apply those insights to waterfall design and the broader hydraulic structures that rely on free-surface flow.

Open-Channel Two-Phase Flow in Rough Rivers — ANSYS Fluent CFD SimulationDescriptionWelcome to the Open-Channel Two-Phase Flow in Rough Rivers CFD Simulation module. This project introduces civil and hydraulic engineers to the world of river hydraulics using ANSYS Fluent. Open-channel flow — water moving with a free surface under gravity — governs how rivers behave, shaping flood patterns, erosion processes, and overall water-resource dynamics. What sets a natural river apart from an idealized channel is the roughness of its bed, which strongly influences the velocity profile and the water surface. This module shows how to represent that roughness realistically and capture its effect on the flow. Within the Hydraulic & Civil: Beginner CFD Training Package, it builds on the waterfall case by moving from free-fall flow into fundamental open-channel hydraulics, applying the two-phase VOF method to a natural watercourse.MethodologyThe workflow begins with creating a basic geometry representing an open channel with a rough bed and applying an appropriate meshing strategy for accurate flow analysis. The two-phase flow is set up by defining the properties of water and air within ANSYS Fluent. A central part of the setup is representing the rough river bed: bed roughness is modeled through surface-roughness parameters or geometric representation, and the model settings are configured so that the roughness properly influences the water flow patterns and velocity profiles. The boundary conditions specify inlet flow rates and outlet conditions to represent the river scenario, along with free-surface and wall boundary conditions for the water surface, the channel walls, and the bed. The solver parameters — including time-stepping and convergence criteria — are configured to suit an open-channel hydraulic simulation, and the solution is monitored for stability throughout.AnalysisPost-processing focuses on extracting meaningful insight from the river flow. Velocity fields and streamlines are visualized to understand the flow behavior over the rough bed, while velocity profiles and water-surface behavior are examined to assess the river's hydraulic characteristics and potential flood scenarios. Free-surface visualization reveals the dynamic water–air interface along the channel. By the end of this project, you'll be able to set up and run a basic open-channel flow simulation with a rough bed in ANSYS Fluent, capture flow patterns and velocity profiles in a natural channel, interpret the free surface and velocity results, and apply those insights to river management, flood control, and erosion-control strategies.

Counterflow within a Canal — ANSYS Fluent CFD SimulationDescriptionThis project uses ANSYS Fluent to simulate counterflow in a canal and analyze the resulting fluid behavior. The setup features a main water stream moving along the canal while a second stream is injected in the opposite direction from a floor-mounted pipe. The opposing jet disturbs the flow and the free surface, creating a localized interaction between the two streams that is characteristic of many practical canal and hydraulic-mixing situations. Within the Hydraulic & Civil: Beginner CFD Training Package, this project extends open-channel modeling to a case where two opposing flows interact, building on the earlier river case toward more complex free-surface behavior.MethodologyThe three-dimensional geometry, built in DesignModeler, represents a straight channel 8 m long with a 3 m × 1 m rectangular cross-section, with a 4 m long pipe of 0.05 m diameter lying along the canal floor. Meshing in ANSYS Meshing yields 256,899 elements, and a transient solver is used. The main channel inflow velocity is 0.3 m/s, while the pipe issues flow at 2 m/s in the opposite direction. The region above the water surface is open to air, represented by a pressure-inlet boundary at 0 Pa gauge for ambient conditions. Because both water and air are present, a VOF multiphase model is employed, with the standard k–ε model for turbulence.AnalysisPost-processing provides 2D and 3D fields of pressure, velocity, and phase volume fraction for water and air. The opposing jet perturbs the free surface and entrains air, producing zones with a locally reduced water volume fraction where the counterflow interacts with the main stream. From these results you can evaluate how the opposing jet disturbs the main flow, how air is entrained at the free surface, and where the strongest mixing and interaction between the two streams occurs.

Hydraulic Jump of Water in a Rectangular Channel — ANSYS Fluent CFD SimulationDescriptionA hydraulic jump is what happens when fast, shallow water abruptly slows down: the flow height rises sharply, velocity drops, and energy is dissipated in a turbulent transition. It's a key phenomenon in open-channel and agricultural water systems — spillways, irrigation canals, and energy-dissipation structures all rely on understanding where and how strongly a jump forms. This project uses ANSYS Fluent to capture that transition and locate exactly where the jump occurs for two different inlet flow rates. Within the Hydraulic & Civil: Beginner CFD Training Package, this project introduces one of the classic phenomena of open-channel flow, applying the two-phase VOF method to a fundamental transition in a simple rectangular channel.MethodologyThe water–air system is modeled with the VOF (Volume of Fluid) multiphase approach, which tracks the free surface between the flowing water and the surrounding ambient air. The fluid domain is built in Design Modeler, and a structured mesh of 231,646 elements is generated in ANSYS Meshing. The case is solved as a steady, pressure-based simulation with gravity included (−9.81 m/s² in the Y-direction). Turbulence is modeled with the standard k-ε model using standard wall treatment, and the VOF model runs with implicit volume-fraction formulation and implicit body forces over two Eulerian phases (air and water). Air enters through a pressure inlet at zero gauge pressure, while water enters through a mass flow inlet. The simulation is run for two inlet water flow rates to compare their effect on the jump. Pressure–velocity coupling uses the SIMPLE scheme, with PRESTO! for pressure, second-order upwind for momentum, and Modified HRIC for the volume fraction.AnalysisThe results show the hydraulic jump forming at different downstream locations depending on flow rate: the jump occurs about 0.9 m downstream for the lower flow rate and about 2.8 m downstream for the higher one — the stronger flow carries its momentum farther before transitioning. From these results you can see how the jump location and strength respond to the inlet conditions and how energy is dissipated across the transition. By the end of this project, you'll be able to set up a free-surface VOF simulation, configure the appropriate solver and discretization schemes for two-phase open-channel flow, and predict where a hydraulic jump forms as a function of inlet conditions.

Pond Overflow — ANSYS Fluent CFD SimulationDescriptionWhen water spills over an ogee overflow and discharges into a pond, the way it behaves depends heavily on whether the flow runs as a free surface or under pressure. Capturing that difference is essential for designing spillways and overflow structures that handle their intended flow safely. In this project, you'll use ANSYS Fluent to simulate water flowing over an ogee overflow into a pond, comparing two distinct flow regimes side by side. Within the Hydraulic & Civil: Beginner CFD Training Package, this project moves from open channels toward hydraulic structures, introducing overflow behavior and the important distinction between free-surface and pressurized flow.MethodologyThe model is built in two dimensions in ANSYS DesignModeler as an ogee overflow leading into a pond, and two separate cases are studied. In the first, the flow is a free surface reaching the overflow at a defined height with a flow rate of 140 kg/s; in the second, the water flows under pressure with a flow rate of 420 kg/s. The geometry is configured in two variants — one that includes an upstream region before the overflow and one that omits it — and the inlet is split into separate water-flow and airflow sections. Meshing is carried out in ANSYS Meshing using a semi-structured grid, with roughly 20,100 elements for the free-flow case and 16,400 for the pressure-flow case. Because both cases involve a moving interface between air and water, a two-phase Volume of Fluid (VOF) model is used, with air defined as the primary phase and water as the secondary phase.AnalysisFrom the results, you'll examine 2D contours of pressure and velocity along with the volume-fraction field that reveals the free surface and the path of the water into the pond. You'll also obtain a plot of static pressure along the flow direction for both models, allowing a direct comparison between the free-surface and pressurized regimes. By the end of this project, you'll be able to set up a two-phase free-surface flow in ANSYS Fluent using the VOF model, configure and compare multiple flow scenarios on a single hydraulic structure, and interpret the results to understand how overflow conditions change the pressure and velocity behavior.

Flood Over a Bridge — ANSYS Fluent CFD SimulationDescriptionA flood occurs when water overflows onto land that is normally dry — when a river exceeds its channel capacity, a levee is overtopped, or rainwater accumulates on saturated ground. Floods are a central concern in hydrology, civil engineering, and public health, and they pose a serious threat to man-made structures in a river's floodplain. This project uses ANSYS Fluent to simulate a flood surging through a dry riverbed and striking a bridge, with the goal of quantifying the forces the flood imposes on the bridge's pillars. Within the Hydraulic & Civil: Beginner CFD Training Package, this project applies free-surface modeling to a practical civil situation — flood loading on infrastructure — and introduces the extraction of structural loads from a CFD result.MethodologyThe geometry is built in Design Modeler and meshed in ANSYS Meshing with an unstructured grid of 844,311 elements. The water–air system is modeled with the VOF (Volume of Fluid) multiphase approach, which tracks the free surface between the advancing flood water and the surrounding air. Water enters the computational domain — a dry river — at a velocity of 10 m/s, representing the incoming flood front. The simulation is run in transient, 3D form with gravity enabled (−9.81 m/s² in the Y-direction), and turbulence is handled with the standard k-ε model. The transient setup is essential here: a flood is an inherently time-dependent event, and capturing how the water front advances and loads the structure over time is the whole point.AnalysisAt the end of the solution, the results show clearly how a flood can damage and ultimately destroy a man-made structure like a bridge. One of the most important factors is the shear stress exerted on the bridge's pillars, which the simulation shows to be considerable. This kind of result has direct engineering value: it can inform the design of bridge pillars capable of withstanding extreme events like floods — choosing pillar shapes and structures that reduce the hydrodynamic loading. By the end of this project, you'll be able to set up a transient 3D free-surface VOF simulation, model a flood front advancing through a domain, and extract structural loads such as shear stress on submerged structures to support resilient civil engineering design.

Cascade Flow over Stepped Hydraulic Structures — ANSYS Fluent CFD SimulationDescriptionWelcome to the Cascade CFD Simulation module. This project introduces civil and hydraulic engineers to the dynamics of cascade structures using ANSYS Fluent. A cascade is a series of steps or drops that water flows over, and it plays a valuable engineering role in dam spillways, urban water features, and stormwater management — controlling the flow while dissipating its energy as it descends. What makes cascade flow distinctive is the stepped flow pattern and the strong aeration and air entrainment it promotes, which enhance both energy dissipation and water quality. Within the Hydraulic & Civil: Beginner CFD Training Package, this project marks the move into dedicated hydraulic structures, introducing stepped-flow energy dissipation as a bridge toward the spillway cases that follow.MethodologyThe workflow begins with creating a basic geometry representing a cascade structure and applying an appropriate meshing strategy for accurate flow analysis. The water properties are defined in ANSYS Fluent, and the boundary conditions are set to represent the cascade scenario — inlet flow rates and outlet conditions, together with wall and free-surface boundary conditions for the cascade steps, the walls, and the water–air interface. The solver parameters, including time-stepping and convergence criteria, are configured to suit a cascade hydraulic simulation, and the solution is monitored for stability and convergence throughout. Because the flow tumbles over the steps and interacts strongly with the surrounding air, the setup captures the air-water interaction central to cascade behavior.AnalysisPost-processing focuses on the flow patterns and energy dissipation over the steps. Velocity fields and streamlines are visualized to understand how the water moves over the stepped structure, while velocity profiles and energy-dissipation characteristics are examined to assess cascade performance and inform design. Air-entrainment patterns are identified to reveal how the cascade promotes aeration as the water descends. By the end of this project, you'll be able to set up and run a basic cascade flow simulation in ANSYS Fluent, capture stepped-flow patterns and energy dissipation, interpret the velocity and aeration results, and apply those insights to cascade design and optimization for dam spillways, urban water features, and stormwater systems.

Ogee Spillway Flow Analysis — ANSYS Fluent CFD SimulationDescriptionWelcome to the Ogee Spillway CFD Simulation module. This project introduces civil and hydraulic engineers to computational fluid dynamics applied to spillway design and analysis using ANSYS Fluent. A spillway is a critical safety component of a dam, regulating the water level and safely passing flood flows, and the ogee (S-shaped) profile is one of the most widely used because it guides the flow smoothly while efficiently dissipating its energy. Understanding the hydraulic behavior of an ogee spillway — its flow pattern, its surface pressures, and how it dissipates energy — is central to effective dam engineering and flood control. Within the Hydraulic & Civil: Beginner CFD Training Package, this project takes the first dedicated look at a spillway, building on the earlier overflow and cascade cases toward a classic hydraulic structure.MethodologyThe workflow begins with creating a basic geometry representing an ogee spillway and applying an appropriate meshing strategy for accurate flow analysis. The water properties are defined in ANSYS Fluent, and the boundary conditions are set to represent the spillway scenario — inlet flow rates and outlet pressure conditions, together with wall and free-surface boundary conditions for the spillway surface and the water–air interface. The solver parameters, including time-stepping and convergence criteria, are configured to suit a spillway hydraulic simulation, and the solution is monitored for stability and convergence throughout. The setup captures the free surface as the water accelerates over the ogee profile, allowing both the flow pattern and the surface loading to be resolved.AnalysisPost-processing focuses on the velocity and pressure behavior over the spillway. Velocity fields and streamlines are visualized to understand how the flow develops along the ogee profile, while pressure profiles along the spillway surface are examined to assess hydraulic loads and potential cavitation risks. The energy-dissipation characteristics are then analyzed to reveal how the spillway reduces the energy of the high-velocity flow and protects downstream structures. By the end of this project, you'll be able to set up and run a basic ogee spillway simulation in ANSYS Fluent, capture flow patterns and surface pressure distributions, interpret the energy-dissipation behavior, and apply those insights to spillway design and performance evaluation for dam engineering and flood control.

Spillway (2-D & Transient), Two-Phase Flow — ANSYS Fluent CFD SimulationDescriptionThis project simulates the two-phase flow of water and air over an ogee spillway — the curved overflow structure used in dams to pass excess water safely downstream. When flow meets an obstruction, the water level rises behind it and accelerates over the crest; an ogee profile is shaped specifically to match the natural nappe of falling water, minimizing pressure problems and maximizing discharge efficiency. Capturing the free water surface as it spills over the crest is the core of the problem and a classic application of free-surface CFD in civil and hydraulic engineering. Within the Hydraulic & Civil: Beginner CFD Training Package, this project builds on the earlier ogee spillway case by solving it as a fully transient two-phase problem, watching the free surface develop over the crest in time.MethodologyThe physics is handled with the Volume of Fluid (VOF) multiphase model, which tracks the sharp air–water interface as it deforms over the spillway, with the standard k-ε model closing the turbulence. Because the whole point is to watch the water move, accelerate, and form its surface profile over the crest, the case is solved as transient. Water enters the computational domain at a mass flow rate of 0.05 kg/s and flows over the spillway against the air phase. The geometry is built in ANSYS Design Modeler and meshed in ANSYS Meshing with a structured mesh of 12,846 elements — structured here because the spillway's smooth, well-defined geometry suits a clean, aligned grid along the flow path.AnalysisContours of pressure, velocity, and phase volume fraction are extracted across the domain, revealing the water surface profile over the crest, the acceleration of the flow down the spillway face, and the pressure distribution along the structure — exactly the quantities a hydraulic engineer uses to assess discharge capacity and surface pressures. The project includes the geometry and mesh file plus a comprehensive training movie walking through the full setup, solution, and extraction of all results. By the end of this project, you'll be able to set up a transient VOF air–water free-surface case, define mass-flow inflow over a curved spillway, apply standard k-ε turbulence, and read the free-surface profile and pressure field from volume-fraction and pressure contours.

Stepped Spillway (Stair Spillway) — ANSYS Fluent CFD SimulationDescriptionWelcome to the Stepped Spillway (Stair Spillway) CFD Simulation module. This project introduces civil and hydraulic engineers to stepped spillways and their analysis using ANSYS Fluent. A stepped spillway replaces the smooth face of a conventional spillway with a series of steps, and this stepped profile dramatically increases energy dissipation, reduces the risk of cavitation, and improves water aeration — advantages that have made it a favored choice in modern dam design. As the capstone of the Hydraulic & Civil: Beginner CFD Training Package, it brings together the two threads developed across the package — hydraulic structures and complex multiphase flow — combining a stepped structure with the strong aeration and energy dissipation that make it the most demanding case in the set.MethodologyThe workflow begins with creating a basic geometry representing a stepped spillway and applying an appropriate meshing strategy for accurate flow analysis. The water properties are defined in ANSYS Fluent, and the boundary conditions are set to represent the stepped spillway scenario — inlet flow rates and outlet pressure conditions, together with wall and free-surface boundary conditions for the stepped surface and the water–air interface. The solver parameters, including time-stepping and convergence criteria, are configured to suit a stepped spillway hydraulic simulation, and the solution is monitored for stability and convergence throughout. The setup is designed to capture the flow tumbling down the steps and the strong air–water interaction that drives the aeration and energy dissipation characteristic of these structures.AnalysisPost-processing focuses on the flow patterns and energy dissipation along the steps. Velocity fields and streamlines are visualized to understand how the water moves over the stepped profile, while the energy-dissipation characteristics are analyzed to assess how efficiently the structure reduces the flow energy from step to step. Air-entrainment patterns are identified to reveal how the stepped spillway promotes aeration as the water descends. By the end of this project, you'll be able to set up and run a basic stepped spillway simulation in ANSYS Fluent, capture stepped-flow patterns and energy dissipation, interpret the aeration behavior, and apply those insights to stepped spillway design and performance evaluation for modern dam engineering and flood control.