Peng Yang

Peng Yang

OpenWALAS on GitHub Email - pycssrc@qq.com

Welcome to OpenWALAS

My title

One new version is released on July 27th, 2023.

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What is it?

main-UI

Fig. 1 Main GUI

multi-model

Fig. 2 Two Vessels

OpenWALAS (Open Wave Load Analysis Software) is a suit of fluid-structural interaction software aiming to numerically calculate the motions, wave loads and hydroelastic responses (springing and whipping) of marine structures in waves, which is based on three-dimensional potential theory and modal superposition principle of elastic structures, as well as Morison’s equation. And the velocity and pressure are respectively solved by 3D boundary element method (BEM) in frequency domain and time domain, considering forward speed, multi-body and nonlinear factors (nonlinear hydrostatic restoring force, nonlinear incident wave exciting force and slamming pressure), as well as the function of eliminating irregular frequencies of floating structures and second-order forces (QTF, middle-field integral and far-field momentum) in frequency domain.

The project of OpenWALAS, maintained by Dr. Peng Yang on GitHub and built originally for Yang’s own research, intends to supply a suit of free (not opensource) software to scientists and engineers all over the world.

Everyone can freely use the software for scientific research and academic activities, but the software must be cited in the published papers or reports. If it is to be used for commercial purposes, it is recommended to purchase genuine software from developers.

OpenWALAS program suit contains the functions of automatic meshing of ship hulls, cut-off hull mesh, straight beam modal analysis, characteristic calculation of transverse section, as well as 3D model display and 2D curve drawing. The software suit contains the GUI program OpenWALAS and five non-GUI core programs: OpenWALAS_PRE, OpenWALAS_FSCM, OpenWALAS_TDGF, OpenWALAS _IORM and OpenWALAS _TIME_RESP. The modules of OpenWALAS_MOOR and OpenWALAS_BLADE are developing, and will be released as soon as possible. The module OpenWALAS_MOOR is to consider complex mooring systems, and the module OpenWALAS_BLADE is to assess aerodynamic performances and elastic vibrations of blades of floating offshore wind turbine.

frame-diagram

Fig. 3 Frame diagram of OpenWALAS

design-draft-FOWT

Fig. 4 Design draft of FOWT (Floating Offshore Wind Turbine) (Ma et al., 2019)

  • OpenWALAS_PRE program for pre-processing, is mainly used to calculate the mode of wetted floating structures from dry modal informtions, in which the structural FEM model is 3D FEM model or beam model.
  • 3D calculation and analysis function in time domain: OpenWALAS_TDGF (time domain green’s function method, called ‘TDGF’) and OpenWALAS_IORM（Inner and outer regions matching of Rankine source, called ‘IORM’) are the core program. The hydrodynamic coefficients are mainly calculated, including impulse response function of radiation forces, impulse response function of diffraction exciting forces, impulse response function of incident exciting forces, impulse response function of sectional wave loads, etc.
  • 3D calculation and analysis function in frequency domain: OpenWALAS_FSCM（forward speed correction method in frequency domain, called ‘FSCM’) is based on the forward speed correction assumption (i.e., low speed and high frequency) boundary element method and Morison’s equation in three-dimensional frequency domain, to assess the influence of forward speed. The hydrodynamic coefficients (such as incident wave exciting force, diffraction wave exciting force, added mass and added damping), motions and wave loads, hydroelastic modal responses, wetted-surface pressures, wave height distributions of surrounding fluid fields, and second-order forces are mainly calculated. It also has the function of eliminating irregular frequency by adding a rigid cover on the inner free surface using the extended integral equation. There are three methods (near-field pressure integral method, middle-field control-surface method and far-field momentum method) are proposed to calculate the second-order forces, including rigid modes and elastic modes.
  • OpenWALAS_TIME_RESP is a calculating program of elastic modal responses and wave loads in time domain, which includes the functions of nonlinear incident force, hydrostatic restoring force, slamming force, Morison’s equation, as well as indirect time-domain method.

How to use it

This web site supplies the executable programs and documentations of OpenWALAS and also provides examples of how you can use it.

- Two ways for running

  • First way: run OpenWALAS wit GUI to input parameters, calculate and post-process, as well as everything else.

  • Second way: command line

    • (a) 3D frequency-domain module: OpenWALAS_PRE -> OpenWALAS_FSCM.
    • (b) 3D indirect time-domain module: OpenWALAS_PRE -> OpenWALAS_FSCM -> OpenWALAS_TIME_RESP.
    • (c) 3D direct time-domain module: OpenWALAS_PRE -> OpenWALAS_TDGF or OpenWALAS_IORM -> OpenWALAS_ TIME_RESP.

- Installation

  • Designed for Linux, Windows and macOS operation system.
  • -Windows: double click ‘OpenWALAS’ directly to install the software.
  • -Linux: double click ‘OpenWALAS’ directly to install the software or compile from the source files.
  • -macOS: double click ‘OpenWALAS’ directly to install the software.
  • The other versions of the executive programs click here .

- Documentation

The documentations cover the basic information of installing and using them.

- Examples

Here’s some examples .

Licensing & Copyright

The author always respects the intellectual property rights and labor achievements, and supports the behavior of sharing software and related documents. Any organization and individual can freely share the program and related documentation within a limited scope, but the following principles should be followed.

  • (a) The projects encourage relevant researchers and authors to carry out joint-research, utilize this program, and further improve the program, so as to contribute to the technology development of global ship and ocean engineering;
  • (b) Copyrights of the software and documentation belongs to the original author;
  • (c) This program shall not be used for any commercial purpose without the permission of the original author, otherwise it will be deemed as infringement;
  • (d) The source and the original author must be cited, if the software and the contents of this document are reprinted. We sincerely hope that you will respect the intellectual copyright. Please quote this program or this website reasonably, correctly and truly in the public papers or reports using this program;
  • (e) For those who do not abide by this statement or illegally use this software and the contents of this document, the rights are reserved according to law.

作者一贯尊重知识产权和劳动成果，并支持分享软件和相关文档的行为，在有限范围内可自由分享本程序和相关文档，但需遵循以下原则：

  • 1、鼓励相关科研人员与作者开展联合研究，发挥本程序作用，并进一步完善程序，为全球船舶与海洋工程技术发展做贡献;
  • 2、程序和文档的版权归原作者所有；
  • 3、未经原作者允许不得将本程序用于任何商业目的，否则将视为侵权；
  • 4、转载或者引用本程序和本文内容请注明来源及原作者。真切希望大家尊重知识版权，在使用到本程序的公开论文或报告中请合理、正确、真实引用本程序或本网站。
  • 5、对于不遵守此声明或者其他违法使用本程序和本文内容者，本人依法保留追究权等。

Release History

  • OpenWALAS-1.0 was originally released in January 2022.

References

Peng Yang

Peng Yang

OpenWALAS on GitHub Email - pycssrc@qq.com