1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Elastic Waves with SPH

  1. Jun 17, 2013 #1
    Hello Everyone,

    I'm trying to solve the following Problem:
    cf0z9rt6arnye9dn0.gif
    (taken from "SPH simulation for seismic behavior of earth structures" - Y.Ono et. al)

    To this end, I wrote a small matlab skript, to be found here. The paper presents results at t=10s and t=20s:
    cf0zdmx4adt9ou8ng.gif

    which my solution reproduces quite accurately if i set kh (the ratio from particle spacing to smoothing length) to 1:
    cf0zgcm29jkbp2czw.gif
    (snapshot taken at t=20)

    However, as soon as I increase kh the solution quickly deteriorates:
    cf0zi4i2ojzjt7618.gif
    (kh=2, snapshot taken at t=5).

    Currently, I think that this is due to the boundary deficiency of SPH. That is, increasing h will lead to larger deficient boundary regions like so:
    cf0zn5q0qf96qqlvw.gif
    cf0zngcvzzyu6dglo.gif
    reconstruction of the derivative of a sine function, top with kh = 2, bottom with kh=8. Code.

    I already tried to:
    - assign densities according to 7b622d669cbc463c46aee50d6a54de51.png
    - adapt h according to h_p = h_init*(rho_init/rho_p), using the densities computed with the formula above
    - introduce CSPM corrections (even though the paper clearly states that the problem should be solvable employing "vanilla" sph only).

    I would be very grateful for any input.

    PS: I hope this is the right subforum

    EDIT: In case anybody was wondering about the kernel
     
    Last edited: Jun 17, 2013
  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?