http://www.k-wave.org/forum/topic/source-term Support for the k-Wave MATLAB toolbox en-US Wed, 13 May 2026 00:47:19 +0000 http://bbpress.org/?v=1.0.2 q http://www.k-wave.org/forum/search.php http://www.k-wave.org/forum/topic/source-term#post-1173 Tue, 15 Jan 2013 10:51:44 +0000 bencox 1173@http://www.k-wave.org/forum/ <p>Hi Chao,</p> <p>kspaceFirstOrder_scaleSourceTerms takes into account the fact that you are inputting the source over a finite region, a voxel, and a finite time, dt.</p> <p>To check your simulation is set up to give you the same units out that you put in, turn off the absorption and propagate a plane wave which won't spread geometrically. You may want to turn off the PML at the edges perpendicular to the wave so it is truly modelled as 1D.</p> <p>Kind regards,</p> <p>Ben </p> http://www.k-wave.org/forum/topic/source-term#post-1172 Sun, 13 Jan 2013 03:14:27 +0000 huangchao 1172@http://www.k-wave.org/forum/ <p>Hi Dr. Cox,</p> <p>Actually, I am trying to use the kspaceFirstOrder3D function to simulate the wave propagation governed by the wave equation (∇^2 - 1/c(r)^2∂^2/∂t^2)p(r,t) = -s(r,t) subjecting to p(r,0)=0, ∂p/∂t|t=0 = 0, where the source term s(r,t) is given and it's obviously not in the unit of pressure, although I called it pressure source in the original post.</p> <p>After studying the k-Wave user manual, I found that the above s(r,t) is corresponding to ∂S_M/∂t in Eq. (2.9) provided there is no velocity soureces. Also, in k-Wave, the source.p is scaled to be unit of S_M so that it can be added in the equation of mass conservation.</p> <p>So to simulate the above inhomogeneous wave equation in my case, I need to integrate s(r,t) first and set the integral values to source.p, then comment the line kspaceFirstOrder_scaleSourceTerms, after that the simulation results from kspaceFirstOrder3D should be consistent to the above wave equation. Is this right?</p> <p>Thanks,<br /> Chao </p> http://www.k-wave.org/forum/topic/source-term#post-1171 Sat, 12 Jan 2013 21:16:31 +0000 bencox 1171@http://www.k-wave.org/forum/ <p>Hi Chao,</p> <p>Probably quickest if you have a look in the k-Wave manual (under documentation). I think Section 2.3 (and surrounding sections) answers your question. If not, please post again.</p> <p>Happy New Year too!</p> <p>Ben </p> http://www.k-wave.org/forum/topic/source-term#post-1170 Fri, 11 Jan 2013 20:49:09 +0000 huangchao 1170@http://www.k-wave.org/forum/ <p>Hi Dr. Cox and Dr. Treeby,</p> <p>I am trying to use the kspaceFirstOrder3D function to simulate wave propagation in media with varying sound speed and with a time varying pressure source term s(r,t) and zero initial conditions. So I wonder using kspaceFirstOrder3D is equivalent to solve which of the following 2nd order wave equations:</p> <p>1. (∂^2/∂t^2 - c(r)^2∇^2)p(r,t) = s(r,t) subjects to p(r,0)=0, ∂p/∂t|t=0 = 0;</p> <p>2. (∇^2 - 1/c(r)^2∂^2/∂t^2)p(r,t) = -s(r,t) subjects to p(r,0)=0, ∂p/∂t|t=0 = 0;</p> <p>Also, are the following settings for the input structure source correct for my case?<br /> source.p0=0;<br /> source.p=s;<br /> source.p_mask=s_mask;<br /> source.p_mode='additive';</p> <p>Thanks a lot for your time and Happy New Year!</p> <p>Best,<br /> Chao </p>