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Project SEA-Stack

SEA-Stack

Open-source simulation for offshore energy systems — from hydrodynamics and structures to moorings and PTO/control, all in a single simulation framework.

Explore system-level design trade-offs in software before committing to costly hardware or tank testing.

LicenseMIT
DevelopersSimocean, NLR, UW-Madison
Funded byU.S. Department of Energy
Releasev1.0.0-beta

Start with fast BEM-based exploration, then progress to higher-fidelity CFD/SPH when needed — within a consistent workflow.

SEA-Stack in action

Short clips from SEA-Stack simulation runs — spanning floating multibody systems, nonlinear moorings, hydraulic PTO/control, and flexible structural response.

5SA

Five-segment attenuator in directional waves — coupled multibody dynamics with hydrodynamic interaction and tension-coloured nonlinear mooring response.

RM3

Reference Model 3 (RM3) two-body wave energy converter — irregular-wave response with hydraulic PTO coupling.

Trimaran FEA

Flexible trimaran hull model — structural deformation under wave loading with Chrono::FEA representation.

SEA-Stack for system design exploration

SEA-Stack is an open-source (MIT-licensed) simulation platform for offshore energy systems, designed for system-level design exploration that captures the coupled interactions between hydrodynamics, structures, moorings, and control.

System Modelling

  • Multibody dynamics (Project Chrono)
  • Coupled hydrodynamics (BEM-based)
  • Robust added mass handling
  • FEA-informed analysis
  • Single- and multi-body systems

Subsystems & Architecture

  • Mooring systems (MoorDyn)
  • PTO systems (hydraulic and mechanical)
  • Control systems (simulation → HiL ready)
  • Arrays and multi-device interactions

Workflows & Access

  • YAML-based workflows (run via executable)
  • C++ API for advanced users
  • Open-source (MIT licensed, no proprietary dependencies)
  • Time-domain simulation framework
  • BEM → CFD/SPH workflows (in development)

SEA-Stack is structured to support workflows spanning BEM-based time-domain simulation and higher-fidelity CFD/SPH comparison and validation. The higher-fidelity path is currently under active development.

Geometry
Hydrodynamics(e.g. BEM-based)

SEA-Stack

Time-domain coupled system model

Coupled subsystems

MooringsPTOControlArrays
Outputs: performance, structural loads, mooring loads, parametric trade-offs

Design decisions affect performance

Changes in geometry, mooring properties, or PTO settings influence device response in waves. The interactive conceptual demo below lets you explore these coupled trade-offs in real time.

Interactive conceptual illustration

Designing offshore energy systems means weighing geometry, mooring layout, PTO (power take-off — motion into electricity), and sea state against outcomes like energy capture, structural loading, and mooring loads. SEA-Stack is built for that kind of coupled exploration — adjust the controls to see how the trade-offs shift.

Energy capture

0.67

Structural load

0.50

Mooring load

0.50

Capabilities

A deeper look at the C++ simulation capabilities and architecture: solvers, couplings, and subsystem components used to assemble engineering workflows.

System simulation

  • Coupled offshore system modelling with multi-body dynamics
  • Articulated joints, FEA flexible bodies, and constraint handling via Project Chrono
  • Dense infinite-frequency added mass directly in the solver mass matrix

Hydrodynamics & waves

  • Linear potential-flow hydrodynamics with BEMIO HDF5 coefficients
  • Nonlinear hydrostatics from instantaneous submerged-volume mesh calculation
  • Regular, irregular, bimodal, and directional wave fields
  • Radiation via RIRF convolution or state-space approximation

Mooring, PTO & control

  • MoorDyn mooring coupling with 3D visualisation and tension colouring
  • Linear spring-damper and rectified hydraulic PTO models
  • Scalar control interface with extensible controller architecture

Workflows & interfaces

  • YAML-driven simulation configuration — no C++ required for standard cases
  • HDF5 results export with provenance metadata
  • Power-matrix campaign mode with sea-state sweeps and annual energy output
  • Modular C++ API and CMake package for downstream integration

Open source access

SEA-Stack is fully open-source under the MIT licence, with source code and pre-built packages for Windows and macOS distributed through the project repository.

Developed through Simocean with NLR and UW-Madison for transparent engineering workflows in offshore and marine energy research.

Public beta release details will be added here as packaging and repository access are finalized.