Elastic Waves with SPH

1. Jun 17, 2013

CarlFaberge

Hello Everyone,

I'm trying to solve the following Problem:

(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:

which my solution reproduces quite accurately if i set kh (the ratio from particle spacing to smoothing length) to 1:

(snapshot taken at t=20)

However, as soon as I increase kh the solution quickly deteriorates:

(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:

reconstruction of the derivative of a sine function, top with kh = 2, bottom with kh=8. Code.

- assign densities according to
- 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