http://www.k-wave.org/forum/topic/acoustic-intensity Support for the k-Wave MATLAB toolbox en-US Wed, 13 May 2026 00:14:24 +0000 http://bbpress.org/?v=1.0.2 q http://www.k-wave.org/forum/search.php http://www.k-wave.org/forum/topic/acoustic-intensity#post-4450 Wed, 09 Apr 2014 20:53:01 +0000 qiangbo 4450@http://www.k-wave.org/forum/ <p>Thanks. It is a great explanation! </p> http://www.k-wave.org/forum/topic/acoustic-intensity#post-4448 Wed, 09 Apr 2014 17:04:44 +0000 Bradley Treeby 4448@http://www.k-wave.org/forum/ <p>Hi qiangbo,</p> <p>Acoustic intensity characterises the flow of acoustic energy in a particular direction in units of W/m^2. The instantaneous acoustic intensity is defined as the product of the acoustic pressure and particle velocity, i.e., I = p * u. As the particle velocity is a vector, so too is the intensity. </p> <p>As an example, consider a plane wave passing through an imaginary surface. The energy that passes through the surface will depend on its orientation relative to the plane wave. Thus, intensity must be a vector quantity.</p> <p>In the special case of a plane wave, the acoustic pressure and particle velocity in the direction of the wave are related by p = c0 * rho0 * u, where c0 and rho0 are the sound speed and mass density of the fluid. Substituting this into I = p * u gives your expression. This is the component of the intensity in the direction of the plane wave.</p> <p>In k-Wave, the intensity is calculated using the more general expression I = p * u. Note that in the current version (v1.0), there are a few issues related to calculating intensity close to the Nyquist limit of 2 grid points per wavelength (see <a href="http://www.k-wave.org/forum/topic/defining-incident-acoustic-plane-wave-intensity">this discussion</a>). This has been improved for the next release.</p> <p>Hope that helps,</p> <p>Brad. </p> http://www.k-wave.org/forum/topic/acoustic-intensity#post-4410 Thu, 03 Apr 2014 20:50:16 +0000 qiangbo 4410@http://www.k-wave.org/forum/ <p>I am wondering what is the definition k-wave used to calculate acoustic intensity. Some papers define acoustic intensity as I = p^2/(rho*c), which is a scalar. But the acoustic intensity from k-wave is a vector. Thanks! </p>