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.

XCHAP – RANS Solver

• RANS method – Fully coupled
• k-ω SST and Explicit Algebraic Stress Model (EASM)
• Structured, Multi-block overlapping grids
• Finite volume formulation
• Propeller modelled with integrated lifting line method or interface to external propeller software
• Computes viscous resistance, wake flow, propeller/hull interaction
• Double Model or Volume of Fluid RANS for Viscous Free Surface

Advanced Features

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 flow predictions for ships using this technique can be executed in an accurate and robust manner.

The default turbulence model is of an Explicit Algebraic Stress type (EASM), and has proven to be especially accurate for stern flow predictions.