Viscous flow around two interacting ships

The primary task of this work package (WP1) is to calculate the flow field around two bodies very close to each other. In real life, this is a ship-to-ship operation. The CFD calculations will be done with software capable of modelling turbulence (DNS, LES, U/RANS) in order to take important viscous effects into account.

The main goals are :

to capture the viscous flow field between two ship hulls at very close distance

to calculate the flow field close to two ships moored in a varying current

find flow quantities (velocity, pressure) that can be visualised and compared to experimental results from PIV measurements in WP2

 

The detailed viscous flow calculations done in WP1 and experiments done in WP2 are motivated by parallel ongoing CFD activities and the need for understanding and get insight into the complex flow patterns. It will also make it possible to investigate situations never met in real life (accidents, hazards,..). The findings in WP1 and WP2 may result in more physical correct models used in real-time simulators (WP3) for actual ship operations.

 

 

Figure 1: Two ships in loading condition

 

Figure 2: Backward facing step and ship-ship operation (flipped 180 deg)

 

We will use different existing CFD software, and they will all be capable of simulating viscous (turbulent) flow. The High Performance Computing resources at NTNU (Notur) will be used.

Basic flow studies may include configurations with cross flow on two ships in loading condition, based on experience with backward/forward facing step simulations, Figs.1 and 2.

Figure 3. Normal ship-ship operation

 

 

In normal operation, the separation distance and length of the two ships are shown in figure 3. The viscous fluid flow in between the ships, both in vertical (depth) and longitudinal (along the ship hull) direction will be studied.