Shipflow

"Improved digital tools for the hydrodynamic design of energy efficient ships – validation, demonstration and introduction to the maritime industry"

 FLOWTECH has just successfully finished a project executed with support from the Swedish Energy Agency (Energimyndigheten). The results of the work include the following:

  • Verification and Validation of CFD simulations of delivered power at full-scale were carried out for ships for which high-quality sea-trial data was collected. Special attention was paid to the effect of roughness on the hull and propeller to improve the accuracy of the simulations. The comparison error for the delivered power was about 1% which shows that the simulations at full scale can very accurately predict power demands of new ships as well as ships in service.

 

  • The study performed within this project showed that the numerical optimization of ship hulls at full-scale could yield higher gains in power savings. The presented optimization process included the propeller-hull interactions, and a clear advantage of self-propulsion-based optimization was observed.

 

  • An efficient and accurate numerical procedure to estimate the decrease of ship speed in wind and waves was developed. It was used to calculate the weather factor of the attained energy efficiency design index for new ships, EEDI, for a tanker. The predictions were compared to the model test results and a database of similar ships. The comparison error was 1% for the resistance and the predicted weather factor was in line with the database values.

 

  • Materials with examples and analyses of the project results illustrating the new possibilities for developing energy-efficient hull shapes were prepared. Several papers for scientific journals were written and the resulst will be presented in the upcoming conferences and workshop on numerical ship hydrodynamics. The results will also be shared with the shipyards and design offices through the company network.

 

A new paper published in Ocean Engineering Journal:

Michal Orych, Sofia Werner, Lars Larsson, 2021. Validation of full-scale delivered power CFD simulations. Volume 238, 15 October 2021, 109654

https://www.sciencedirect.com/science/article/pii/S0029801821010301

 

Abstract:

Verification and Validation of CFD simulations of delivered power at full-scale are carried out for a single screw cargo vessel. Numerical simulations are performed with a steady-state RANS method coupled with a body force propeller model based on a lifting line theory. There are no significant differences in the uncertainty levels between model and full-scale computations. The finest grid exhibits the numerical uncertainty of 1.40% at full-scale. Computed results are compared with sea trial data for three sister ships. Special attention is paid to the effect of roughness on the hull and propeller. The comparison error for the delivered power is about 1% which is significantly lower than the experimental uncertainty.

Keywords:

Delivered power; Full-scale; Hull roughness; Self-propulsion; Uncertainty; Validation; Verification; CFD

 

SHIPFLOW 7.0

The main feature of the new major release is the MOTIONS 7 module for seakeeping and dynamics of floating vessels and structures.

MOTIONS 7 highlights:

  • most advanced fully nonlinear, unsteady potential flow commercial code on the market
  • multiple, arbitrary floating bodies
  • regular, irregular and short crested waves
  • mooring lines, fenders, spring attachments (e.g. to carriage)
  • external force model interface ( Flettner rotors, wing sails, fins )
  • applications: ships, ship to ship interactions, semi-submersibles, floating platforms,  floating wind mills

 

 
 
 
 

SHIPFLOW 6.6.00

SHIPFLOW 6.6 includes developments and refinements in the following areas:

- Full scale power prediction

- Roughness effects

- Parametric appendages

- Inbuilt Wageningen B-Series propeller geometry 

- Twin-skeg gridding

- Free sinkage and trim calculations with VOF solver

- Appendages and selfpropulsion with VOF solver

SHIPFLOW 6.5.00

SHIPFLOW 6.5 intorduces a new evaluation method for the wave resistance computed by XPAN. The new predictions give more reliable results for a wide range of ships including container vessels, tankers and bulk carriers. This improvement as well as other small changes and bug fixes makes it a highly recommended update for the users.

 Resistance

Publications

FLOWTECH's staff actively works with research and applications of Computational Fluid Dynamics to ship hydrodynamics, propulsion, optimization. The results are often published in papers, articles and books, see: Complete list of publications .

 

 

 SHIPFLOW 6.4.00

SHIPFLOW version 6.4.00 is now available for downloaded from our home page, www.flowtech.se. Here are the major news:

  • Extended Result Reporting
  • Customizable automatic postprocessing
  • Added support for surface roughness effects
  • New appendages
  • New licensing system

 

Training GOTHENBURG 10-12 october 2017

Come and learn how to best use the SHIPFLOW Software!

 

Ship in short crested waves

Figure. Ship in short crested waves

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Seminar

Nanjing Tianfu Software Co. Ltd organize together with FLOWTECH a two days seminar in Dalian China. The seminar will cover hull optimization and ship motions in waves using the CAESES and SHIPFLOW software. For more information see Link

Date: 8 - 9 May 2017

Location: Dalian China

Contact: NJTF for further information and registration

 

Parametric roll

The video shows the motion of the DTC container ship experience parametric roll. The prediction was produced with the release 6.3 of SHIPFLOW MOTIONS.

In this simulation the wave encounter frequency is approximately twice the natural roll frequency and the wavelength of the encountering wave is approximately equal to the ship length. The ship was given an initial roll of one degree in order to trigger the roll. No viscous damping was added in this case.

 

Added resistance in regular head sea wavesSHIPFLOW 6.2

The major news are:

  • Improved accuracy of ship motion and added resistance in waves
  • Improved MOTIONS robustness
  • Added user defined damping coefficients e.g. roll damping
  • Multiple improvements to overlapping grid algorithm
Read more ...