• MOSES simulation for RAO

    Go Ogawa
    Go Ogawa
    Good morning, I was hoping someone could provide me some information to improve my understanding on how MOSES works. I am currently using MOSES to find the forces on a cargo and comparing this with a manual hand calculation. My questions are: 1…
    • 7 days ago
    • MAXSURF | MOSES | SACS | OpenWindPower
    • MAXSURF | MOSES | SACS | OpenWindPower Forum
  • moses motions statistics along different reference system

    doug graham
    doug graham
    I'm trying to post-process a frequency-domain analysis. In particular, in the attached example, the command fp_std *BT12 produces the RAOs on point *BT12 of the body "barge" along the body axes. Clearly also the motions statistics for the enviroment…
    • Answered
    • 2 months ago
    • MAXSURF | MOSES | SACS | OpenWindPower
    • MAXSURF | MOSES | SACS | OpenWindPower Forum
  • Negative Weight and WPA no RAO Calculation at MOSES

    muhammad fahmi
    muhammad fahmi
    Hello! I am a new user. I try to get RAO from my model, but there was no RAO graph on the result. I got negative weight and WPA on the result, but I confuse how can I get the negative for both of them. here is the result of the calculation. the red…
    • over 3 years ago
    • MAXSURF | MOSES | SACS | OpenWindPower
    • MAXSURF | MOSES | SACS | OpenWindPower Forum
  • PDF

    A BRIEF NOTE ON INERTIA & DAMPING COEFFICIENTS in MOSES

    Bit-na Seo
    Bit-na Seo
    This document explains how the added inertia coefficients and linearized damping coefficients are calculated and reported in MOSES. Often asked questions are also discussed at the end of the document.
    • DampingNotes_v.1.pdf
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    • over 4 years ago
    • MAXSURF | MOSES | SACS | OpenWindPower
    • MAXSURF I MOSES I SACS I OpenWindPower Files
  • RE: Dynamic Analysis in SACS

    Geoff McDonald
    Geoff McDonald
    Camille, You can use RAO's in conjunction with a wave height and period to generate a resulting inertial load on the structure which can then be solved to check the member stresses. However, SACS does not perform a dynamic analysis for this response…
    • over 6 years ago
    • MAXSURF | MOSES | SACS | OpenWindPower
    • MAXSURF | MOSES | SACS | OpenWindPower Forum
  • Remove all viscous damping terms

    Jason Forcier
    Jason Forcier
    Q: How can I remove all viscous damping terms in the damping matrix when computing RAOs? REV 5.03 A: Do not include any Morrison elements, #PLATE or #AREA commands. Also, the Tanaka damping must be turned off using the A_TANAKA BNAME NONE command, and…
    • over 7 years ago
    • MAXSURF | MOSES | SACS | OpenWindPower
    • MAXSURF | MOSES | SACS | OpenWindPower - Wiki
  • Calculate the RAOS before a time domain analysis

    Jason Forcier
    Jason Forcier
    Q: Do I need to calculate the RAOS before a time domain analysis if I want to include radiation and (or) Coriolis forces? REV 7.05 A: The drift force has three components. 1. mean drift which is always present (we will call this static drift) 2…
    • over 7 years ago
    • MAXSURF | MOSES | SACS | OpenWindPower
    • MAXSURF | MOSES | SACS | OpenWindPower - Wiki
  • unmatched RAO output

    reza amarosa
    reza amarosa
    Dear colleague, Below is attaced RAO graph on heave motion. When periods goes up, automatically the frequency is getting smaller. It sign that barge heave amplitude is closed relatively to wave high. But, on below graph the maxima value is not 1…
    • over 7 years ago
    • MAXSURF | MOSES | SACS | OpenWindPower
    • MAXSURF | MOSES | SACS | OpenWindPower Forum
  • Forces computed with g_pressure

    Jason Forcier
    Jason Forcier
    Q: Is it necessary to generate RAO after the 'g_pressure' command if I am doing a mooring in time domain? REV 7.01 A: It depends on what parts of the drift force you want included. You need to compute the RAOs before you perform a time domain analysis…
    • over 7 years ago
    • MAXSURF | MOSES | SACS | OpenWindPower
    • MAXSURF | MOSES | SACS | OpenWindPower - Wiki
  • Change the TANAKA factor and produce RAOs for different values in the same output file

    Jason Forcier
    Jason Forcier
    Q: Before REV 7.02 I could change the TANAKA factor and produce RAOs for different values in the same output file. How do I do this now? REV 7.02 A: The following should produce what you want: hydrodynamics g_pressure -heading 90 end $ freq_resp…
    • over 7 years ago
    • MAXSURF | MOSES | SACS | OpenWindPower
    • MAXSURF | MOSES | SACS | OpenWindPower - Wiki
  • RAOs for a multi body analysis

    Jason Forcier
    Jason Forcier
    Q: If I use the command FR_POINT &BODY(CG DECK) will I get the RAOs of the motion of the DECK cg in its current position? REV 5.05 A: Maybe. The FR_POINT does yield the RAOs of a point about its mean position. These RAOs are represented in the body…
    • over 7 years ago
    • MAXSURF | MOSES | SACS | OpenWindPower
    • MAXSURF | MOSES | SACS | OpenWindPower - Wiki
  • Solutions of the RAOs differ depending on number of headings

    Jason Forcier
    Jason Forcier
    Q: We have found that the solutions of the RAOs differ depending on the number of headings which were run for the G_PRESSURE command. Shouldn't they be the same? REV 5.10 A: MOSES uses the solution for the previous heading as an initial estimate for…
    • over 7 years ago
    • MAXSURF | MOSES | SACS | OpenWindPower
    • MAXSURF | MOSES | SACS | OpenWindPower - Wiki
  • Periods for statistics of Roll motion

    Jason Forcier
    Jason Forcier
    Q: If one does not specify the periods around the peak of the Roll RAO curve, will MOSES statistics of Roll motion results be inaccurate? REV 6.02 A: In general, your statement is correct, and it is always good practice to provide a reasonable refinement…
    • over 7 years ago
    • MAXSURF | MOSES | SACS | OpenWindPower
    • MAXSURF | MOSES | SACS | OpenWindPower - Wiki
  • Hydrodynamic interaction when calculating hydrodynamic coefficients and RAOs

    Georgina Maldonado-Aguirre
    Georgina Maldonado-Aguirre
    Q: Does MOSES consider hydrodynamic interaction among multiple bodies when calculating the hydrodynamic coefficients and RAOs? REV 7.00 A: The precise answer is, not in general. There are two alternatives, however. First, a body can interact with an…
    • over 1 year ago
    • MAXSURF | MOSES | SACS | OpenWindPower
    • MAXSURF | MOSES | SACS | OpenWindPower - Wiki
  • ERROR: RAO Computation Did Not Converge

    Jason Forcier
    Jason Forcier
    Q: Why do I get ERROR: RAO Computation Did Not Converge when I am trying to compute RAOs? REV 7.06 A: This error is because of one of the following: Way too big of damping, Way too big of stiffness, or No mass is defined.
    • over 7 years ago
    • MAXSURF | MOSES | SACS | OpenWindPower
    • MAXSURF | MOSES | SACS | OpenWindPower - Wiki
  • Vessel Speed Computation in Moses

    Yuni Ari Wibowo
    Yuni Ari Wibowo
    Hi, Currently I'm computing tanker speed in MOSES by inputing the option of "-speed" after command RAO, I do it in various models of speed (0, 5, 10, 15 & 20 knots). But when I check the RAO of each model, the speed of vessel doesn't give any significat…
    • over 7 years ago
    • MAXSURF | MOSES | SACS | OpenWindPower
    • MAXSURF | MOSES | SACS | OpenWindPower Forum
  • Inclusion of Vessel Speed in RAO computation

    Richard Smith
    Richard Smith
    I am currently computing the forces on cargo with a vessel in transit. The vessel speed is 12 knots and is a relatively simple barge shape (with some interesting bow features). Using the '-speed' option appears to not have the desired effect of shifting…
    • over 7 years ago
    • MAXSURF | MOSES | SACS | OpenWindPower
    • MAXSURF | MOSES | SACS | OpenWindPower Forum