Cavitation is a phenomenon affected considerably by the underlying pressure waves that occur on similar timeand length scales as the bubble dynamics. Thus appropriate representation of wave dynamics within numericalframeworks is of paramount importance for the prediction of the phase change process in the nozzle as well as thesubsequent spray formation. In this paper we focus on investigating the sensitivity of the wave dynamics within acompressible Large Eddy Simulation framework with regards to downstream geometry and boundary representation.Diesel was used as working fluid and was injected at various pressures through a micro-channel. Results interms of vapour fraction, velocity and pressure are compared with the experimental data of Winklhofer [30, 31]. Thedownstream domain length and reflectivity properties are shown to exert a significant effect on in-nozzle processes.