Viscous flow solver for ship resistance and propeller hull interaction.
Advanced viscous flow solver
Detailed predictions of the wake are required for design of propellers and for looking at the interaction with appendages. This calls for an advanced viscous flow method. SHIPFLOW uses an unconventional technique, which combines a very stable numerical scheme with other advanced features, such as a turbulence model especially developed for ship stern flow and a novel gridding technique. The viscous flow RANS solver, XCHAP, can be used for computing the double model solution or the viscous free surface. Depending on the type of ship, speed and what effects are studied the user can choose which modules to use. To enhance the stability of the solution the differential equations are discretized considering the magnitude and direction of the flow of information and non-physical fluctuations in the solution are suppressed. Full scale computations using this technique can be made without problems. The default turbulence model is of the algebraic stress type (EASM), and has proven to be especially accurate for stern flow predictions.
XCHAP
- RANS method
- Fully coupled
- k-w SST and explicit algebraic stress model (EASM)
- Multi-block overlapping grids.
- Finite volume formulation
- Propeller by internal lifting line or interface to external propeller programme iteratively linked.
- Computes viscous resistance, wake flow, propeller/hull interaction.
- Double Model or Volume of Fluid RANS method for simulation of Viscous Free Surface.
- MPI is implemented to speed up computations on multi core machines and clusters of machines.
XGRID
- Creates the grid used viscous free surface and double model computations
- Uses offsets as input
- Automatic offset generation from STL or IGES format
- Various hull configuration types: monohull, catamaran, trimaran, twinskeg...
Reporting
- Automatically generated report on html format created after each SHIPFLOW run.
- Report contains customizable standard images and tables.
- Format similar to and easily comparable to tank test report.