Use of OpenFOAM in Modelling of wavestructure interactions Lifen Chen Supervisors: Dr JunZang, Dr Andrew Hillis, Prof Andrew Plummer Architecture and Civil Engineering department University of Bath [email protected] Bath HPC symposium 4th, June, 2013 Bath, UK Background Ocean waves: wind generated waves Irregular waves Intermediate and deep waters Approximations 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 OpenFOAM Default 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: 15712120 Cores: 4 cores Computational time: 5 days Size 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!