  We illustrate a time and memory efficient application of Runge-Kutta
discontinuous Galerkin (RKDG) methods for the simulation of the ultrasounds
advection in moving fluids. In particular, this study addresses to the analysis
of transit-time ultrasonic meters which rely on the propagation of acoustic
waves to measure fluids flow rate. Accurate and efficient simulations of the
physics related to the transport of ultrasounds are therefore crucial for
studying and enhancing these devices. Starting from the description of the
linearized Euler equations (LEE) model and presenting the general theory of
explicit-time DG methods for hyperbolic systems, we then motivate the use of a
spectral basis and introduce a novel high-accuracy method for the imposition of
absorbing and resistive walls which analyses the incident wave direction across
the boundary surface. The proposed implementation is both accurate and
efficient, making it suitable for industrial applications of acoustic wave
propagation.
