{ "metadata": { "name": "", "signature": "sha256:97e555d042bfefd57c2df46c9164b543d1b3777851e08a95cefdb104e8f7d6e2" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "code", "collapsed": false, "input": [ "from SimPEG import *\n", "import scipy\n", "%pylab inline" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Populating the interactive namespace from numpy and matplotlib\n" ] } ], "prompt_number": 2 }, { "cell_type": "code", "collapsed": false, "input": [ "cs = 0.5\n", "hx = np.ones(500)*cs\n", "hy = np.ones(500)*cs\n", "mesh = Mesh.TensorMesh([hx, hy], 'CC')" ], "language": "python", "metadata": {}, "outputs": [], "prompt_number": 3 }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Acoustic Wave equation in time domain (1st order form)" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "$ \\rho\\frac{\\partial p}{\\partial t} = \\nabla \\cdot \\vec{u}+\\frac{\\partial s}{\\partial t}\\delta(\\vec{r}-\\vec{r}_s)$\n", "\n", "$ \\mu^{-1}\\frac{\\partial \\vec{u}}{\\partial t} = \\nabla p$" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Add damping term" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "$ \\rho[\\frac{\\partial p}{\\partial t} + \\sigma p] = \\nabla \\cdot \\vec{u}+\\frac{\\partial s}{\\partial t}\\delta(\\vec{r}-\\vec{r}_s)$\n", "\n", "$ \\mu^{-1}[\\frac{\\partial \\vec{u}}{\\partial t}+\\sigma \\vec{u}] = \\nabla p$" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Discretized form" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "$ \\mathbf{diag}(\\rho)\\frac{\\mathbf{p}^{n+1}-\\mathbf{p}^{n}}{\\triangle t} + \\mathbf{diag}(\\rho\\sigma)\\mathbf{p}^n = \\mathbf{Div} \\mathbf{u}^{n}+\\mathbf{M}^{cc -1}\\frac{\\mathbf{s}^{n+1}-\\mathbf{s}^{n}}{\\triangle t}$ \n", "\n", "\n", "$ \\mathbf{diag}(\\mathbf{Av}^{f}_{cc}\\mu^{-1})\\frac{\\mathbf{u}^{n+1}-\\mathbf{u}^{n}}{\\triangle t} + \\mathbf{diag}(\\mathbf{Av}^{f}_{cc}\\mu^{-1}\\sigma)\\mathbf{u}^{n+1}= \\mathbf{Grad} \\mathbf{p}^{n+1}$" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "