New Wave Theory by Tromans (1991)

Dear Sir,

Is SACS able to generate wave profile according to "New Wave Theory" proposed by Tromans (1991) ??

Refer to paper below

Tromans P.S., Anatürk A. R., Hagameijer P. 1991. A new model for kinematics of large ocean waves –
Application as a design wave. Proc. First Int. Offshore and Polar Engng. Conf., pp 64 – 71, Edinburgh, UK

If it is not possible. Could you please list down this request for next version of SACS?

Regards,

Kasiphon

  • Kasiphon,

    You are correct in that the random wave approach is currently limited to linear (Airy wave) components from a Fourier series. We are currently developing a nonlinear random wave approach that will be available in a future release of SACS.

    If you want to model nonlinear waves in SACS right now, you will be limited to the deterministic nonlinear waves available in the seastate module.

    Regards,

    Geoff

    Answer Verified By: Kasiphon Kurojjanawong 

  • Hi Geoff

    As you mentioned about 'random wave generation' in wave response module.

    I have one question about this. 

    As my understand about this, SACS use Fourier series to break down wave spectrum to to a number of 'linear' regular wave (airy).

    How to let SACS consider about the nonlinear part like the attached picture below?

    What i found from this module is..... the maximum crest elevation of random wave profile generated by SACS is quite lower than 'nonlinear regular wave i.e. stoke 5th'..probably about 10-15%........This lead to a question from many party when i start using this option.

    Could you please recommend to way to solve this problem in SACS?

    Regards,

    Kasiphon

  • Kasiphon,

    The supported wave theories in SACS are listed in section 4.3 of the Seastate Manual and the New Wave theory is not listed in the list of included theories. I have included the list of supported wave theories below:

    1. ‘AIRY’ Airy (or linear) wave theory
    2. ‘AIRC’ Classic Airy theory (no crest or trough)
    3. ‘STOK’ Stokes’ Fifth Order Theory
    4. ‘STRE’ Stream Function theory including current effects
    5. ‘STRN’ Stream Function Theory excluding current effects
    6. ‘CNOI’ Cnoidal Theory
    7. ‘SOLI’ Solitary Wave Theory

    I will add the Tromans New Wave theory to the list of requested features for SACS, but I can't promise that it will be implemented in the next version as there are many features requested for SACS. In the meantime, you may try running a random wave analysis using the wave response module.

    Regards,


    Geoff