DescriptionThis project simulates a floating vessel's motion on water using the dynamic mesh method in ANSYS Fluent. The vessel is positioned at the center of a three-part computational domain, designed so its center of gravity sits along the vertical axis for simulation convenience. The geometry is built in 3D in Design Modeler, and meshed in ANSYS Meshing with an unstructured grid near the vessel and a structured grid elsewhere, totaling 902,808 elements.MethodologyBecause the vessel's motion requires the mesh to deform continuously around it, the Dynamic Mesh model is used, combining smoothing, which adjusts mesh boundaries without changing node count or connectivity, with remeshing, which reconstructs cells that become too distorted when boundary displacement is large relative to local cell size. The domain is divided into a small moving zone around the vessel, a surrounding deforming zone, and a larger stationary outer zone, with the vessel and its moving zone treated as a rigid body via the Six Degrees of Freedom (6-DOF) model. Since the vessel is physically constrained to only vertical translation and rotation about its central axis, a UDF restricts the 6-DOF motion down to these two degrees of freedom, with the vessel's center of gravity and rotation axis specified explicitly in the rigid body setup. The water and air phases are captured with the VOF multiphase model, air above and water below, both entering horizontally at 1.44 m/s and exiting at atmospheric pressure, with an Open Channel boundary condition at the outlet defining the water level. Given the fundamentally time-dependent nature of dynamic mesh motion, the simulation runs transient, covering 7 seconds at a 0.01 second time step.AnalysisThe results include 2D pressure contours on the vessel and 2D velocity and volume fraction contours in the surrounding air-water region, taken at the final second of the simulation, along with time-history plots of the vessel's vertical displacement and rotation angle over the full 7 seconds. These plots show the oscillation amplitude in both displacement and rotation decreasing over time, with the vessel's motion becoming effectively damped by the seventh second. At that point, the vessel settles near a vertical position of z = 0.021 and a rotation angle of Y_theta = -1.338, indicating it reaches a stable floating equilibrium consistent with the physical damping expected in this kind of fluid-structure interaction.

Submarine Movement in Water by Dynamic Mesh (1-DOF), ANSYS FluentDescriptionThis simulation models the motion of a submarine in water using the Dynamic Mesh method in ANSYS Fluent, with a computational domain containing both air and water phases at a defined water level, with the submarine positioned within this domain.The submarine geometry was designed first, followed by a computational domain incorporating two-phase (air-water) flow around it. Both were modeled in 3D using Design Modeler. The domain includes distinct inlet and outlet sections, with symmetry conditions applied to the four surrounding faces.Meshing was carried out in ANSYS Meshing using an unstructured mesh totaling 316,846 elements.MethodologySince the submarine moves within the computational domain, affecting the surrounding grid elements, the mesh requires continuous, time-dependent updates based on the displacement occurring at adjacent mesh boundaries. This is achieved through the dynamic mesh model, applying smoothing and remeshing methods, with the submarine's wall defined as a Rigid Body.The submarine is constrained to a single degree of freedom (1-DOF), permitted to rotate only about its central axis (x-axis), with no translational or additional rotational motion. This rotational behavior is defined through a UDF, with rotational velocity varying between +1.5 rad/s and -1.5 rad/s over the 0–3 second simulation window.The rigid body settings also require specifying the spatial coordinates of the submarine's center of gravity and its axis of rotation.Since the domain contains two phases, the VOF multiphase model is applied, with air occupying the upper region and water the lower region. To represent the submarine operating in open sea conditions, wave behavior is introduced via the open channel wave boundary condition — incoming water enters at an average velocity of 10 m/s along the horizontal (x-axis), with the wave trough set at -10.16 m and its crest at 0 m. Inlet airflow enters at atmospheric pressure (zero relative pressure), with air discharged at atmospheric pressure as well.Given the dynamic mesh foundation of this model, the simulation is run as a transient (time-dependent) case, spanning 3 seconds with a time step of 0.01 seconds — necessarily unsteady due to the dynamic mesh method employed.ConclusionThe results include 2D contours of velocity and volume fraction for both water and air phases, along with 2D pathlines around the submarine — captured on a plane perpendicular to the submarine's horizontal axis (parallel to the Y-Z plane) at multiple points throughout the simulation.Consistent with the defined UDF, the submarine exhibits reciprocating rotational motion about its central axis, alternating between clockwise and counterclockwise rotation over the course of the simulation.

Submarine Design Optimization using Adjoint Solver (RBF Method), ANSYS FluentDescriptionWhen a structure moves at a given speed through a continuous fluid, its body experiences forces from that fluid — as with a submarine moving through water, where hydrodynamic forces act on its surface. One of the most significant of these is drag force, acting horizontally against the submarine's direction of travel and creating resistance to its motion.Minimizing drag is a key consideration in submarine design and construction, with the magnitude of drag force depending directly on the geometric shape and dimensions of the hull. This project applies an optimization process to the submarine's geometry to reduce drag using CFD analysis.Several optimization methods exist for shape design, and ANSYS Fluent provides an adjoint solver tool specifically for geometric optimization — capable of iteratively adjusting target geometry dimensions through a structured solution process until an optimal shape is achieved.This simulation applies adjoint-solver-based optimization to reduce drag force across three stages: first, a baseline simulation is run on a standard submarine geometry to establish initial drag; second, the adjoint solution identifies which regions of the submarine's geometry are most sensitive to drag force; and third, optimization is performed to reduce the target drag value by a defined percentage.The 3D geometry — a simple submerged submarine — was modeled in Design Modeler and meshed in ANSYS Meshing using an unstructured grid of 258,938 cells.MethodologyThe submarine's configuration is optimized based on drag force reduction. An initial simulation establishes the baseline drag by modeling water flow around the submarine. The Design tab handles the optimization process itself.Drag force is first defined as the target quantity, followed by selecting discretization methods for the adjoint solver in the Method section. Running the adjoint solution then yields a shape sensitivity distribution, identifying which regions of the geometry most strongly influence drag.The final optimization step uses the Design tool with the polynomial morphing method, again selecting drag force as the objective. A target percentage decrease is specified, and a bounded region around the model is defined to constrain geometric changes to that space. The optimization itself runs through the gradient-based optimizer.ResultThe baseline drag force measured 11.485855 N; following adjoint-solver optimization, this dropped to 6.4377518 N — a 44% reduction, confirming the optimization was successfully applied.This reduction stemmed from geometric changes to the hull dimensions, examined using the iso-clip tool to compare pre- and post-optimization geometry. In cross-section, dimensions shifted from 0.5066175×0.5063399 to 0.4386431×0.453043; in the side profile, from 4.353052×0.6 to 4.09195906×0.5952543.Since drag force correlates directly with cross-sectional area, the reduced cross-section directly explains the drag decrease. Total drag force is the sum of pressure drag and frictional drag: pressure drag arises from the pressure differential across the submarine's two sides — smaller cross-sections reduce this differential — while frictional drag depends on side surface area, meaning reduced surface area lowers frictional resistance as well.

Horizontal Axis Tidal Turbine, Paper Numerical Validation, ANSYS Fluent CFD Simulation TrainingDescriptionThis project simulates a Horizontal Axis Tidal Turbine using ANSYS Fluent, with results compared and validated against the published article "Performance of horizontal axis tidal current turbine by blade configuration."Water flows at a velocity of 1 m/s and passes over the turbine; as the flow collides with the turbine blades, it generates torque, producing rotational motion in the blades, which in turn induces a rotational flow pattern in the surrounding water.The 3D model uses S814-type airfoil sections for the turbine blades. Since the airfoil cross-section scales up or down along the blade length (based on airfoil chord length), each individual airfoil section — 16 in total — was imported as a set of coordinate points and drawn in SOLIDWORKS at a specific angle and distance from the central axis. These sections were then imported into Design Modeler for integrated blade construction.Design Modeler was used to model a three-bladed turbine. A dedicated cylindrical region was created around the blades to capture the circulating water flow, surrounded by a rectangular domain representing free-stream water flow. Blade geometry — including chord size for each airfoil section and its angle of inclination relative to the central axis — followed Table 3 of the referenced paper.Meshing was performed in ANSYS Meshing using an unstructured grid, with boundary layer mesh applied to the blade surfaces to improve accuracy, totaling 4,270,222 elements.MethodologyThe Moving Reference Frame (MRF) technique was used to simulate blade rotation, with the cylindrical region defined in frame motion mode at a rotational speed of 191 rpm about the turbine's central horizontal axis.ConclusionTurbine power (P) was calculated based on the torque applied to each blade (T), from which the pressure coefficient (Cp) was derived. These results were compared and validated against the corresponding values in Table 2 of the referenced article, which provides input and reference values used to compute the final torque and pressure coefficient figures.The power and pressure coefficient formulas follow the article's methodology, with the present CFD results compared directly against the paper's reported values in the accompanying results table.

FSI Method for Water Turbine CFD Simulation in ANSYS FluentIntroductionThis study investigates the water flow around a vertical water turbine using an unsteady, transient CFD simulation in ANSYS Fluent. The turbine blades are assumed to be affected by the passing fluid flow, such that the fluid impedes forces on the turbine body, causing deformation and resizing of the blade structure. Since the problem involves the simultaneous solution of both fluid and solid domains, a Fluid-Structure Interaction (FSI) approach is employed, coupling the fluid flow solution with a Transient Structural analysis through system coupling. The simulation is solved using a pressure-based, transient solver, with gravitational effects neglected.Geometry and MeshThe three-dimensional model was designed in Design Modeler, consisting of a large cubic fluid domain with the water turbine positioned inside as the solid domain. The domain was discretized using an unstructured mesh generated in ANSYS Meshing, resulting in a total element count of 523,202.MethodologyTurbulent flow behavior was resolved using the standard k-epsilon viscous model with standard wall functions applied for near-wall treatment. The dynamic mesh approach, incorporating smoothing and remeshing methods, was coupled with a system coupling dynamic mesh zone to capture the two-way interaction between the fluid flow and the deforming turbine structure. At the inlet, a velocity-inlet boundary condition was applied with a velocity magnitude of 1.5 m/s, while a pressure-outlet condition with 0 Pa gauge pressure was set at the outlet. The turbine blades and fixed surfaces were defined as stationary walls. The SIMPLE algorithm was used for pressure-velocity coupling, with second-order upwind discretization applied to pressure and momentum, and first-order upwind discretization applied to turbulent kinetic energy and turbulent dissipation rate. The simulation was initialized using the standard initialization method with an x-velocity of 1.5 m/s.Results and ConclusionThe coupled FSI solution captures the dynamic interaction between the water flow and the turbine blade structure, allowing the deformation behavior of the blades under fluid loading to be evaluated alongside the surrounding flow field characteristics, providing insight into the structural response of the turbine under realistic unsteady hydrodynamic conditions.

Sloshing Tank, ANSYS Fluent CFD Simulation TrainingDescriptionExperimental and numerical studies consistently demonstrate the importance of fluid sloshing within a tank on the maneuverability of floating vessels such as ships and boats. Several key laboratory studies inform this area of research, including measurements of sloshing dynamics within a tank, experimental-statistical analysis of sloshing wave impact loads on shell tank models, verification of numerical sloshing results against experimental data from scaled reservoir sections at different filling heights, investigation of long-term sloshing pressures accounting for impact-induced vibration, and experimental studies of pressure distribution from liquid sloshing in rectangular tanks.The computational domain represents a tank containing LNG fuel and air, incorporating several rows of internal joints and walls designed to restrict fluid movement. This reduces friction between fluid layers, since the inertia of fluid moving within the tank can otherwise affect the stability of the fuel carrier vehicle.The 2D tank geometry was modeled in Design Modeler, measuring 1 m in length and 0.7 m in width. Six rows of internal dividers, each 0.35 m high and 0.04 m thick, separate the fluid layers, with the geometry segmented to support a structured mesh. Since ANSYS Fluent relies on the finite volume method, mesh quality is critical; a structured mesh was accordingly generated for the tank using ANSYS Meshing.MethodologyThe simulation was set up using a pressure-based solver with absolute velocity formulation, run as a transient case with a 0.005 s time step. Gravity was enabled at -9.81 m/s² in the Y-direction, while the energy equation was disabled.Tank motion was defined through a UDF applying an oscillating zone velocity along the X-direction following a sinusoidal function, with the rotation axis fixed along Z. All walls were assigned a no-slip condition, and the reference pressure point was set at X = 0.00 m, Y = 0.25 m.The VOF multiphase model was used, with air as the primary phase and water as the secondary phase, applying implicit formulation, sharp interface modeling, and implicit body force, alongside an enabled level-set method for improved interface tracking; open channel flow was disabled. A surface tension coefficient of 0.0725 N/m was defined for the air-water interaction.Solution methods included SIMPLE for pressure-velocity coupling, PRESTO! for pressure interpolation, and QUICK schemes for both momentum and level-set discretization, with a compressive scheme applied to VOF implementation. The domain was initialized uniformly at zero, followed by a patch applied over the region X: -10 m to +10 m, Y: 0 to 0.25 m, setting static pressure as ρ_w·g·(1 − y/H_w) and a water volume fraction of 1.0. Static pressure was monitored throughout the simulation at a point located at Y = 0.0525 m.ConclusionThe simulation captures the oscillatory sloshing behavior of fluid within the tank as it responds to the applied motion, tracking the resulting pressure fluctuations at the monitored point over time. These results characterize how internal baffles and fluid inertia influence sloshing loads — information directly relevant to assessing structural and stability impacts on the fuel carrier vessel under realistic operating motion.

Oscillatory Wave and its Effect on Fin Motion, ANSYS Fluent CFD TrainingDescriptionThis project simulates the rotational motion of a fin within a two-phase flow field, driven by an oscillatory wave generated through ANSYS Fluent.The 2D geometry was designed in Design Modeler, divided into three main regions: structured, unstructured, and stationary. Meshing was carried out in ANSYS Meshing, totaling 120,049 elements. An unstructured mesh was applied specifically in the region surrounding the fin, since this area undergoes deformation through the dynamic mesh process and requires high flexibility to accommodate remeshing, while the remaining regions retain a structured mesh.The model is inherently unsteady, since it simulates the fin's rotational motion under a time-dependent oscillating fluid wave. Gravitational effects were included at 9.81 m/s² along the y-axis, given their influence on the torque acting on the fin.MethodologyThe two-phase flow was modeled using the VOF model, with air as the primary phase and water as the secondary phase, with no interaction or mass transfer between them. The motion of a rigid wall and its attached boundaries generates an oscillatory wave within the domain, which applies compressive force and shear stress to the fin mounted on the domain floor — causing the fin to rotate about its vertical axis as a rigid body.Since the problem requires boundary displacement, a dynamic mesh technique was used to capture the fluid flow, with a UDF defining the reciprocating motion of the scaffold wall responsible for generating the waveform. The simulation ran for 100 seconds with a time step of 0.001 s.Dynamic mesh smoothing was applied using a spring constant of 0.7, 500 iterations, and a convergence tolerance of 0.001, combined with the remeshing method using local cell sizing; spring-based smoothing alone was not used. The fin is constrained to a single degree of freedom (1-DOF), rotating about the z-axis around its pivot point, exhibiting reciprocating motion driven by wave impact. The moment of inertia applied to the fin was set to 0.1147 kg·m², equivalent to that of a rotating rod about its endpoint (I = 1/3·mL²).ConclusionThe results include 2D contours of pressure, velocity, and the volume fraction of air and water, along with pathlines captured at t = 2s. By enabling the write motion history option within the 6-DOF definition settings, the fin's x-y position and angular orientation were recorded over time as a dataset, producing a graph of the fin's angular displacement across the full 22.5-second simulation window.

Sub-Oceanic Volcanic Activity — ANSYS Fluent CFD SimulationDescriptionThis project simulates sub-oceanic volcanic activity using ANSYS Fluent and the Volume of Fluid (VOF) multiphase model — a complex and critical environmental scenario. Sub-oceanic volcanic eruptions play a crucial role in shaping the planet's oceans and climate, and their accurate simulation supports oceanographic research, ocean engineering, tsunami forecasting, and weather and climate science. The simulation captures the interaction between water, lava, and vapor on the sea floor, combining wave modeling with the extreme thermal effects of an eruption. As the capstone of the Open Channel Flow: Beginner CFD Training Package, it is the most complex and specialized case in the set, bringing together free-surface waves, multiphase interaction, and mass transfer in a single environmental problem.MethodologyThe underwater topography is designed in ANSYS Design Modeler and meshed in ANSYS Meshing with an unstructured grid optimized for a challenging multiphase scenario. The VOF multiphase model is configured to capture the interaction between water, lava, and vapor. The Open Channel Flow model is enabled together with the Open Channel Wave boundary submodel for realistic wave simulation, and Fifth-Order Stokes Wave Theory is implemented for accurate surface-wave patterns. Mass transfer is modeled using the Lee model to represent evaporation and condensation — capturing the vapor generation caused by the extreme eruption temperatures and its effect on the ocean hydrodynamics.AnalysisPost-processing focuses on the interaction between the eruption and the sea surface: the disruption of the wave patterns due to the volcanic activity, and the hydrodynamic effects of vapor generation on the ocean surface dynamics. From these results you can interpret the complex multiphase behavior, validate the model against known oceanic and volcanic phenomena, and connect the findings to real-world applications such as tsunami prediction, ocean engineering, and climate research. By the end of this project, you'll be able to set up a VOF simulation coupling water, lava, and vapor, apply the open-channel wave submodel with Fifth-Order Stokes wave theory, implement evaporation and condensation with the Lee mass-transfer model, and interpret the wave–eruption interaction that governs this environmental scenario.

DescriptionThis project simulates pollution transport in a meandering river using ANSYS Fluent, investigated through CFD analysis. Water pollution is the contamination of water bodies — usually the result of human activity — in a way that harms their legitimate uses. Such pollution prevents a body of water from delivering the ecosystem services it would otherwise provide, and it is broadly classified as either surface water pollution or groundwater pollution.The model was built in 3D using Design Modeler. The river's width at the inlet is 14.035 m, and the pollutant enters through two circular profiles, each 3 m in diameter. Meshing was performed in ANSYS Meshing, producing 762,433 elements. Because of the time-dependent nature of the problem, a transient solver was used.MethodologyThis study employs the VOF (Volume of Fluid) multiphase model to solve the two-phase flow field. To represent the free surface of the river, the open channel option within the multiphase module was enabled, allowing the air–water interface and the gravity-driven surface flow to be captured accurately.Pollutant enters the river through two circular inlet profiles near its start and then diffuses into the water. Because the pollutant is less dense than water, it accumulates at the river's surface, and the flow carries it downstream, spreading the contamination along the channel.The Realizable k-epsilon viscous model with scalable wall functions was used to resolve the turbulent flow. Pressure-velocity coupling was handled with the SIMPLE scheme. A second-order upwind scheme was applied to the momentum equations, while a first-order upwind scheme was used for the turbulent kinetic energy and turbulent dissipation rate. Water enters the domain at 35 m/s, and the pollutant enters at 5 m/s.ConclusionOnce the solution was complete, contours of velocity, pressure, pollutant volume fraction, water volume fraction, eddy viscosity, and streamlines were extracted and presented across different time steps.As the results show, the pollutant enters the river through the two circular inlet profiles and gradually diffuses across the water surface over time. Driven by the river's flow, the pollution spreads along the free surface and ultimately leads to widespread contamination of the channel.

Pollution Spread in a Stagnant River, ANSYS Fluent TrainingDescriptionThis project simulates the entry and spread of a pollutant into a stagnant river using ANSYS Fluent.The core of this case is open-channel flow — flow in a channel or river whose upper surface is open to the atmosphere and free to deform, rather than being fully enclosed by walls. In open-channel problems the position and shape of the free surface is part of the solution, and gravity governs how the water and anything riding on it settle and move. A river receiving a discharge is a natural example: the pollutant enters at the surface and spreads across it, so tracking that free surface is essential, which is exactly what the open-channel (free-surface VOF) approach is built for.The application itself is an environmental one. Water pollution from industrial waste is a serious concern: chemical by-products discharged into rivers endanger aquatic life and can enter the human food chain through it, causing disease. Simulating how a pollutant disperses once it reaches a river helps predict how far and how fast contamination travels.The 3-D geometry was built in Design Modeler, with a river inlet width of 11.05 m. The domain was meshed in ANSYS Meshing with 161,562 elements, and because the spreading process evolves in time, a transient solver is used.Simulation MethodologyThe two phases — water and pollutant — are handled with the VOF multiphase model. The pollutant enters through a non-uniform profile partway along the river and diffuses into the water. Because its density is lower than that of water, it floats and spreads along the free surface. Turbulence is solved with the realizable k-ε model using scalable wall functions, pressure-velocity coupling is SIMPLE, and momentum and the volume fraction use second-order upwind discretization. The river water itself is initially stagnant, and the pollutant enters at 8 m/s.Results & ConclusionAfter solving, contours of velocity, pressure, and pollutant volume fraction were obtained. The results show the pollutant progressively diffusing into the river water over time, with the pressure near the pollutant inlet higher than elsewhere. The cross-sectional pressure contour also shows pressure increasing with depth, as expected for a body of water under gravity.