The problem of wave height in wave making

JiamingLiuJiamingLiu
edited May 2022 in DualSPHysics v5.0

Dear all,

Recently, I have been using Piston+AWAS to simulate wave propagation. However, the wave height I calculated will be higher than the expected range as a whole. Here are the details of my wave condition and "_Def" file.

Water depth: 4m. Wave height: 0.05m. Wave period:1.2s. Wavelength:1.94m.

(After downloading the attachment, you need to remove ". txt" from the file name.)

And the following is the wave height measurement results of the several probs in the "elevation" file.

image.png

As shown in the figure above, although the overall wave height meets the requirements, there is a displacement about one Dp higher than the expected wave height range. I don't know how to explain this phenomenon and eliminate this influence. Can anyone answer it?

Best regards!

Comments

  • JiamingLiuJiamingLiu
    image.png


  • Asalih3dAsalih3d
    1. Convergence study based on dp, does this change results?
    2. Make domain bigger, move the piston further to the left, does this change results?
    3. Have you used a wave gauge to check the initial water height? Please do not forget that, when generating a set of particles, then some times particle layers can be added/removed add the top when using fillbox, drawbox etc. This means the initial water level can be higher/lower than expected. This would explain one dp higher in your case. If you want to check if this is the case without doing a lot of work, make the resolution much finer and see if the discrepancy shrinks

    Kind regards

  • JiamingLiuJiamingLiu
    https://forums.dual.sphysics.org/discussion/comment/5247#Comment_5247

    Thank you for your reply!

    I haven't simulated at other resolutions yet, because I guess any particle resolution simulation should ensure the symmetry of wave surface change. At first, I thought it was caused by simulating the second-order regular wave, but even if I adjusted it to the first-order wave (the wave function is a simple trigonometric function), this still exists.

    In addition, I don't understand why I set the water depth to 0.4m, but under still water conditions, the wave gauges in measuretool will be higher or lower than 0.4m. Is it caused by the interface between particles at the particle edge rather than the particle center?

    image.png


    What causes the "Please do not forget that, when generating a set of particles, then some times particle layers can be added/removed add the top when using fillbox, drawbox etc." you say?


    Best regards!

  • Asalih3dAsalih3d


    https://forums.dual.sphysics.org/discussion/comment/5250#Comment_5250

    To answer the last part of your post, you measure more / less than 0.4 m, because your particles are actually not placed where you think. They are a bit above or below depending on resolution - this is just how the GenCase algorithm works.

    So you have to make sure that your particle layer ends at around 0.4 - dp/2 to get really close to 0.4

    Kind regards

  • JiamingLiuJiamingLiu

    Thank you for your reply!

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