Numerical Absorbing Boundary Conditions Based on a Damped Wave Equation for Pseudospectral Time-Domain Acoustic Simulations

<table>(a) The <svg height="11.375" id="M209" style="vertical-align:-0.16379pt" version="1.1" viewbox="0 0 32.612499 11.375" width="32.612499" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<g transform="matrix(.017,-0,0,-.017,.062,11.112)"><path d="M493 503l-29 -4q-13 56 -28 80q-13 22 -35.5 29.5t-78.5 7.5h-76q-22 0 -27.5 -5t-5.5 -27v-238h103q66 0 82.5 12t25.5 62h29v-193h-29q-9 54 -25.5 67t-82.5 13h-103v-181q0 -64 15 -78.5t84 -19.5v-28h-272v28q61 5 74.5 19.5t13.5 78.5v399q0 64 -13 78t-72 19v28
h440q1 -40 10 -147z" id="x46"></path></g><g transform="matrix(.017,-0,0,-.017,8.732,11.112)"><path d="M257 449q92 0 154 -65t62 -158q0 -112 -67 -175t-150 -63q-98 0 -158.5 66.5t-60.5 154.5q0 59 21 106.5t54.5 75.5t71 43t73.5 15zM244 416q-48 0 -81 -47t-33 -128q0 -96 38 -158t99 -62q51 0 82 43.5t31 139.5q0 91 -36 151.5t-100 60.5z" id="x6F"></path></g><g transform="matrix(.017,-0,0,-.017,17.401,11.112)"><path d="M861 0h-263v28q61 5 73 22t12 97l-4 408h-4l-244 -548h-20l-224 534h-2l-15 -285q-5 -98 -3 -166q1 -34 19.5 -45t72.5 -17v-28h-233v28q45 5 62.5 17t22.5 43q11 65 19 183l14 208q3 36 3.5 55t-2.5 37.5t-6.5 25t-16.5 13t-25.5 8t-39.5 4.5v28h164l228 -501l232 501
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</svg> of the PML is depicted with the optimum profile equation (<a href="https://static.hindawi.com/articles/tswj/volume-2014/285945/figures/#EEq14">14</a>). (b) In this gray scale plot we show the reflection coefficient obtained in the PML simulation versus angle and frequency. (c) The <svg height="15.4" id="M210" style="vertical-align:-3.39066pt" version="1.1" viewbox="0 0 38.674999 15.4" width="38.674999" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<g transform="matrix(.017,-0,0,-.017,.062,11.112)"><path d="M372 352v-2q176 -27 176 -159q0 -99 -95 -151q-73 -40 -196 -40h-221v28q65 5 78.5 19t13.5 76v404q0 63 -12 77t-72 18v28h257q102 0 150 -34q26 -18 41 -48.5t15 -65.5q0 -111 -135 -150zM213 362h47q80 0 117.5 32t37.5 96q0 56 -33 92t-100 36q-41 0 -56 -10
q-13 -8 -13 -50v-196zM213 328v-203q0 -54 17 -72.5t66 -18.5q67 1 110.5 37t43.5 110q0 147 -192 147h-45z" id="x42"></path></g><g transform="matrix(.017,-0,0,-.017,10.058,11.112)"><path d="M956 650v-28q-52 -7 -69 -22.5t-39 -77.5q-60 -175 -165 -533h-31l-175 499h-2l-163 -499h-31l-164 535q-18 60 -36 76.5t-65 21.5v28h243v-28q-53 -7 -63 -18.5t3 -49.5l122 -412h2l162 499h29l175 -500h2q87 277 113 401q12 45 0.5 59t-68.5 21v28h220z" id="x57"></path></g>
<g transform="matrix(.012,-0,0,-.012,26.562,15.187)"><path d="M412 140l28 -9q0 -2 -35 -131h-373v23q112 112 161 170q59 70 92 127t33 115q0 63 -31 98t-86 35q-75 0 -137 -93l-22 20l57 81q55 59 135 59q69 0 118.5 -46.5t49.5 -122.5q0 -62 -29.5 -114t-102.5 -130l-141 -149h186q42 0 58.5 10.5t38.5 56.5z" id="x32"></path></g><g transform="matrix(.012,-0,0,-.012,32.274,15.187)"><path d="M241 635q53 0 94 -28.5t63.5 -76t33.5 -102.5t11 -116q0 -58 -11 -112.5t-34 -103.5t-63.5 -78.5t-94.5 -29.5t-95 28t-64.5 75t-34.5 102.5t-11 118.5q0 58 11.5 112.5t34.5 103t64.5 78t95.5 29.5zM238 602q-32 0 -55.5 -25t-35.5 -68t-17.5 -91t-5.5 -105
q0 -76 10 -138.5t37 -107.5t69 -45q32 0 55.5 25t35.5 68.5t17.5 91.5t5.5 105t-5.5 105.5t-18 92t-36 68t-56.5 24.5z" id="x30"></path></g>
</svg> is plotted again versus angle and frequency.</table>

The Scientific World Journal

fig6

Figure 6

Figure 6: Numerical Absorbing Boundary Conditions Based on a Damped Wave Equation for Pseudospectral Time-Domain Acoustic Simulations 