DFBI and Solution History Integration in Simcenter STAR-CCM+: Unlocking post processing options for Marine Simulations

After years of development, Simcenter STAR-CCM+ 2502 introduces a game-changing feature that Naval Architects and CFD specialists have been requesting for years: full integration of Dynamic Fluid-Body Interaction (DFBI) with Solution Histories (.simh files). This leap forward transforms how we visualize and analyze transient simulations involving moving bodies.

The Pain

Historically, creating powerful animations from transient results that included DFBI bodies was severely limited. DFBI bodies couldn’t be included as inputs to Solution Histories files. We were forced to rely on bulky workarounds involving hardcopies or complex workflows to adjust viewpoints. This was extremely inflexible and often required re-running entire simulations just to get the desired post-processing results.

What has changed in Version 2502

The latest release brings comprehensive DFBI support to Solution Histories, opening up entirely new possibilities for marine simulation workflows:

Core Capabilities

• Time-dependent expressions and DFBI reports as annotations: Create dynamic annotations that update with your simulation timeline
• Animated DFBI displayers: Directly animate DFBI elements from simh files without additional processing
• Managed time histories: Track coordinate systems and DFBI body motions over time with full representation support
• Multi-body DFBI support: Handle complex scenarios involving multiple interacting bodies

Motion-Following Animations

One of the most exciting new capabilities is the ability to create motion-following animations effortlessly. By connecting a scene’s view to a recorded DFBI coordinate system, you can generate “first-person view” animations that follow the motion of the DFBI body. This provides an entirely new perspective on physical phenomena, particularly valuable for understanding vessel dynamics, wake interactions, and body responses in complex sea states.

Preparation is Key

To demonstrate the power of this integration, consider a complex test case: a fast boat pulling a tube (tuber). This scenario involves:

• Multiple overset regions with two 6-DOF DFBI bodies connected via a catenary
• Moving outer domain with wave forcing
• Self-propulsion simulation using virtual disks
• Volume of Fluid (VOF) method with Adaptive Mesh Refinement (AMR)
• Maneuvering workflow with Simulation Operations controlling the boat’s surfaces based on vessel orientation

Previously, this type of simulation required PNG data dumps to create animations after completion. With the new simh + DFBI integration, all post-processing can be handled elegantly from a single workflow.

While the new capabilities are powerful, there’s one critical lesson I learned: preparation before running is essential. Here’s what you should do:

1. Create follow motions for your DFBI bodies: Right-click on each body and create appropriate motions. Set up typical motion decompositions such as X translation, XY translation, and planar motion before running
2. Configure your SIMH file: Include all necessary functions, bodies, boundaries, and iso-surfaces. DFBI couplings, motions, and coordinate systems will be automatically captured
   
3. Set up managed coordinate systems: Create different coordinate systems for various perspectives which will make post-processing seamless later. The connection to the motion is done by selecting the coordinate system in Managed Coordinate Systems and in the Scenes > View > Coordinate System.
   
   
4. Enable lossy compression: Use 2-digit precision (or your preferred level) to significantly reduce file sizes without sacrificing meaningful data
5. Prepare custom annotations: Define annotations for key parameters like vessel power, speed, and control surface deflections using reports and field functions

Creating these Follow Motions and coordinate systems upfront is easy and takes minimal time. Skipping this step makes decomposing DFBI motion during post-processing impossible.

Advanced Visualization Techniques

The integration enables sophisticated visualization approaches that were previously impractical:

• Path tracking: Overlay DFBI bodies onto plot annotations showing their trajectories using DFBI Report vs DFBI Report plots with simh representations
  
• Advanced rendering with CAD overlays: Use CAD representations overlayed on DFBI bodies with managed transforms for photorealistic animations
  
• Force and moment visualization: Animate all forces acting on bodies using DFBI displayers set to simh representations, with transforms following the body motion
  
• Custom annotations: Leverage the new Solution Time Report in field functions and expressions to create dynamic annotations that update with simulation time

Technical Tips and Tricks

Working with Reports and Field Functions

• Set representations to “Solution View Rep” in your reports to enable time-dependent functionality
  
• Use the new Solution Time Report (which can take simh representations) anywhere you previously used $Time
  
• Reference reports in field functions using the ${{FunctionNameReport}} syntax
• DFBI and Enclosed Angle reports can now take representations, enabling their use in annotations and plots

Debugging Your Setup

If something seems off or you’re confused about what’s being recorded, here’s a quick debugging trick: rescan the simh file, load any state, and check under the simh representation node. You’ll find a complete summary of all recorded objects at that state.

Conclusion

The integration of DFBI with Solution Histories in Simcenter STAR-CCM+ 2502 represents a major leap forward for marine simulation workflows. Working with vessel dynamics, maneuvering simulations, or any scenario involving moving bodies, subjected to fluid forces, this update transforms possibilities. You can now create and adjust all desired visualizations and generate compelling animations even with Screenplay tool.