  A form of the conservation equations for fluid dynamics is presented, deduced
using slightly less restrictive hypothesis than those necessary to obtain the
Westervelt equation. This formulation accounts for full wave diffraction,
nonlinearity, and thermoviscous dissipative effects. A two-dimensional finite
volume method using the Roe linearization was implemented to obtain numerically
the solution of the proposed equations. In order to validate the code, two
different tests have been performed: one against a special Taylor shock-like
analytic solution, the other against published results on a High Intensity
Focused Ultrasound (HIFU) system, both with satisfactory results. The code,
available under an open source license, is written for parallel execution on a
Graphics Processing Unit (GPU), thus improving performance by a factor of over
60 when compared to the standard serial execution finite volume code CLAWPACK
4.6.1, which has been used as reference for the implementation logic as well.
