use of openfoam in modelling of wave-structure interactions
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Use of OpenFOAM in Modelling of wave-structure interactions
Lifen ChenSupervisors: Dr JunZang, Dr Andrew Hillis, Prof Andrew PlummerArchitecture and Civil Engineering departmentUniversity of Bath lc499@bath.ac.uk
Bath HPC symposium 4th, June, 2013Bath, UK
Background
Ocean waves: wind generated waves
Irregular waves
Intermediate and deep watersApproximations
Regular waves: sine/ cosine function
Background
Wave motion: Wave amplitude/elevation Water depth Wave length
Background
Background Computational Fluid Dynamic (CFD): OpenFOAM
Open Source C++ library
Suitable for use in wide ranges of problems
Parallel processing capability of OpenFOAMDefault
Domain decomposition
openMPI
Terminal commands decomposePar
mpirun --hostfile <machines> -np <nProcs> <foamExec> <otherArgs> -parallel > log &
reconstructPar
Cases
Computational domain:
30m × 2m × 1.01m (half domain)
8 cases: various wave parameters
Zang, J. and Taylor, P. H etal.(2010)
Steep wave and breaking wave impact on offshore wind turbine foundations—ringing revisited
25th IWWWFB, China
Computational Cost (Multi-cores)
Cells: 15712120Cores: 4 coresComputational time: 5 daysSize of output files: 90GB
Cases: ?Static mesh Dynamic mesh
Results
Has been applied in ocean engineering successfully.
Can predict wave loading on the fixed structure correctly.
In adaptions of the source code…
A series of trials: Boundary conditions mesh type and resolution wave parameters…..
Running in parallel (Aquila)OpenFOAM-2.1.0 vs. OpenFOAM-1.5
PC vs. Aquila
testing
1. Boundary conditions:
attempted: totoalPressure for output boundary PC: stable Aquila: dump after 7s
modified to: zeroGradient PC: stable Aquila: stable
2. Running the case PC: 4 cores Aquila: 4 processors
Running in parallel (Aquila)
t = 5s
t = 10s
t = 15s
t = 20s
t = 25s
Green line : PC results, red line: Aquila results
Future work Simulation interactions between waves and
floating bodies. dynamic mesh
Simulation interactions between waves and real WECs.
complex geometries and structures’ shape
Increase computational cost
Thank you!
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