Motivation

Whether rising fuel prices, their availability, declining charter rates or new requirements for exhaust emissions, all these challenges are now reflected in a modern ship design. The hull form optimization with the tools of CFD thereby plays an essential role in achieving the objectives of better fuel efficiency.

Method

For designing a hull optimized ship Neptun's portfolio contains the following practices:

  • The hull form optimization starts usually with lines modelling in NAPA – a leading tool not only for surface creation but also to control the whole ship design process.
  • Neptun is offering two types of CFD calculations subsequently to the hull form definition. Typically the first wave resistance analysis can be carried out with the potential flow solver called ν–SHALLO developed by HSVA. At the second step of optimization the resistance of the hull will be used. The ship`s hull will be imported into CAESES® by FRIENDSHIP SYSTEMS AG which is a simulation driven CAE design tool wherein the parameterization of the bulbous bow/hull takes place. While generating a certain amount of variations the wave resistance is calculated by ν–SHALLO for each bulb/hull option in order to find the best and therefore harmonious form with the rest of the hull.
  • For viscous flow simulation such as wake field distribution or trim analysis are of interest standard RANSE solvers in connection with the software tool OpenFOAM are used.
  • In case of a bulbous bow retrofit the ship`s hull will be also imported into CAESES® by FRIENDSHIP SYSTEMS AG for parameterization the bulbous bow to figure out a new bulb form which fits best to the existing hull and the new operational profile for a more efficient sailing under new market conditions.