# Advances in Vibroacoustics and Aeroacoustics of Aerospace and Automotive Systems
## 2 The Present Issue  
We are deeply honored to be the guest editors of this thematic issue, which includes original articles and reviews of interest for the scientific community working on these subjects, as well as for industrial R&D departments. We are particularly grateful to the several leaders in these areas who decided to honor us with their valuable contributions. We want to thank them and their collaborators for the effort they have done for publishing their works in this issue of _Applied Sciences_. We are equally thankful to many colleagues who have helped us evaluating and reviewing these manuscripts with substantial improvements. In particular, we appreciate the editor-in-chief of _Applied Sciences_ for inviting us to edit this topic issue and the staff of the editorial office who supported the entire process. The purpose of this special issue is to highlight the latest advances in vibroacoustics and aeroacoustics applied to aerospace and automotive industries. In proposing this wide topic, we wanted to give scientists and engineers the opportunity to publish their studies of current interest, both in the theoretical and experimental fields of vibration, sound generation, and radiation; and passive and active noise control approaches, which can be of interest for assessing vibroacoustics characteristics of aerospace and automotive vehicles. In particular, we have tried to include articles focusing on the introduction of new approaches and methodologies in the vibroacoustics and aeroacoustics fields. This issue provides access to several articles encompassing the aforementioned themes. In the first article [16], an innovative integrated design verification process is described, based on the bridging between a new semiempirical jet noise model and a hybrid finite-element method/statistical energy analysis (FEM/SEA) approach, for calculating the acceleration produced at the payload and equipment level within the structure of Vega-C Launcher, vibrating under the external acoustic forcing field. The result is a verification method allowing for accurate prediction of the vibroacoustics in the launcher interior, using limited computational resources and without resorting to computational fluid dynamics (CFD) data. Another paper of this issue [17], estimated the internal aerodynamic noise due to valve flow in a simple constriction-expansion pipe (a pressure relief device), by combining the large eddy simulation technique with a wavenumber-frequency analysis, which made it possible to decompose the fluctuating pressure into the incompressible hydrodynamic pressure and compressible acoustic pressure. The results showed that the acoustic pressure fluctuations in a pipe could be separatedfrom the incompressible ones. This made it possible to obtain accurate information about the acoustic power, which could be used to assess the likelihood of a piping system failure due to acoustic-induced vibration, along with information about the acoustic power spectrum of each acoustic mode, which could be used to facilitate the systematic mitigation of the potential acoustic-induced vibration in piping systems. In [18], flow-induced vibrations and the sound radiation of flexible plate structures of different thickness mounted in a rigid plate were experimentally investigated. Therefore, flow properties and turbulent boundary layer parameters were determined through measurements with a hot-wire anemometer in an aeroacoustic wind tunnel. Furthermore, the excitation of the vibrating plate was examined by laser scanning vibrometry. In [19], fully-resolved rotor-fuselage interactional aerodynamics was used as the forcing term in a model based on the Euler-Bernoulli equation, aiming to simulate helicopter tail-boom vibration. The model was based on linear beam analysis and captured the effect of the blade-passing as well as the effect of the changing force direction on the boom. Results for the tail-boom vibration served to demonstrate the strong effect of aerodynamics on tail-boom aeroelastic behavior.