http://www.k-wave.org/forum/topic/about-sound-speed-in-lossy-media Support for the k-Wave MATLAB toolbox en-US Tue, 12 May 2026 23:40:27 +0000 http://bbpress.org/?v=1.0.2 q http://www.k-wave.org/forum/search.php http://www.k-wave.org/forum/topic/about-sound-speed-in-lossy-media#post-293 Wed, 08 Feb 2012 04:00:42 +0000 Bradley Treeby 293@http://www.k-wave.org/forum/ <p>Hi Chao,</p> <p>c_0 in the equation of state you give is the isentropic sound speed (sometimes called the thermodynamic sound speed). It's defined by c_0^2 = (dP / dRho), where P and Rho are the total pressure and density and the differential is evaluated at constant entropy. In a lossy medium, it's not this but the phase speed that depends on frequency. Given a dispersion relation defined with a complex wavenumber k, the phase speed is usually defined as c_p = w / k_real. In k-Wave, this dependence is modelled by the dispersion term.</p> <p>I hope that helps. I think there's some information about c_0 and c_p for Stokes' equation in the chapter on absorption in Kinsler and Frey.</p> <p>Brad. </p> http://www.k-wave.org/forum/topic/about-sound-speed-in-lossy-media#post-292 Wed, 08 Feb 2012 02:08:28 +0000 huangchao 292@http://www.k-wave.org/forum/ <p>Hi, Dr. Cox and Dr. Treeby,</p> <p>I am confused about what's the meaning of c_0 in the equation of state in lossy media, which is:</p> <p>p(r,t) = c_0(r)^2 * rho(r,t) + absp_term + disp_term</p> <p>In lossy media, the sound speed depends on the frequency. In this case, what's the frequency does c_0 correspond to?</p> <p>Thank you very much!</p> <p>Best,<br /> Chao </p>