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Current goals
- CFD
- T
- wing T
ank Experiments
- Identification of important design features
- Validation of OpenFOAM for predicting resistance
Predictions of added resistance in waves Using OpenFOAM Bjrn Windn - - PowerPoint PPT Presentation
Predictions of added resistance in waves Using OpenFOAM Bjrn Windn - - PowerPoint PPT Presentation
Predictions of added resistance in waves Using OpenFOAM Bjrn Windn Fluid Structure Interactions Research Group University of Southampton 1 Current goals CFD T owing T ank Experiments Identification of important design
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Building a model step by step
- Fixed Wigley hull in small
amplitude waves
- Correlation of amplitude
and phase
- Error monitoring when
complexity is added
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Progress
- Wave propagation studies
- Created a modified version of interFoam
- Coupling of snappyHexMesh and refineMesh for
free surface refinement
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Wave propagation
- Aprox 25-30 cells per wave height and length is sufficient
in small amplitude waves (λ/H ~ 65)
- Sufficient means that the waves retain 95% of their
energy at a distance 3*λ from the inlet.
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Modified interFoam (interWaveFoam)
- Included “wave” modification in given regions specified
by a waveDict
- Crude modification of velocity to conform to a specified
target veloity
- U =U 0−U target∗Cx , y , zU target
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Meshing
- High λ/H with equal requirements for cell density for λ
and H means high AR to save cells.
- High AR does not work well with sHM
- Standard sHM cannot split cells in specific directions
- nly
- refineMesh can split cells in any specified direction
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Meshing issues
- Wave propagation
- Hull/fluid interaction
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Meshing issues
- Issues with using snappyHexMesh together with refineMesh
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Solution?
- Modify sHM to deal with single-direction cell splitting
and thereby retain the continuous quality check.
- Refine in different regions with different tools.
- If the boundary layer mesh thickness is well specified,
refineMesh can be set to ignore cells at a certain distance from the surface.
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What's going on here?
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What's going on here?
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