Acoustic waves

This test case is similar to the Euler one: Single-phase acoustic waves. However, a bubble is added in the middle of the domain. To recall, this is a plain pressure field where a source term is used to generate one-way acoustic waves. This work constitutes an adaptation of the work of Maeda & Colonius for single-phase flows [MC17] to a multiphase system of equations. The waves here have a sinusoidal shape. 4 pulses are sent at a frequency of 300 kHz and have a pressure amplitude of 10 kPa. This case is a 2D Cartesian test case. The domain is only composed of water. The source term is located at 10.e-3 m in x and y directions and pulses are directed toward the x direction. This test is referenced in ./libTests/referenceTestCases/PUEq/2D/acousticWave/planeSinusoidalPulse/. The corresponding uncommented line in ECOGEN.xml is:

<testCase>./libTests/referenceTestCases/PUEq/2D/acousticWave/planeSinusoidalPulse/</testCase>

The initial characteristics of the run are:

Characteristic	Value
Dimension	40.e-3 m x 20.e-3 m
Initial mesh size	200 x 100
AMR max level	0
Boundary conditions	non-reflecting
Final solution time	25.e-6 s
Solution printing frequency	5.e-7 s
Precision	2nd order (MC)

Results are shown in Fig. 92 where one can observe the one-way pulses from a point source, therefore spreading cylindrically (2D here) but with a main direction (x direction). The pulses are reflected from the interactions with the bubble (in black).

Fig. 92 One-way sinusoidal acoustic waves in water interacting with a bubble. Visualization using Paraview software.