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We consider the convected Helmholtz equation modeling linear acoustic propagation at a fixed frequency in a subsonic flow around a scattering object. The flow is supposed to be uniform in the exterior domain far from the object, and…

Numerical Analysis · Mathematics 2014-05-16 Fabien Casenave , Alexandre Ern , Guillaume Sylvand

We predict the development and propagation of the fluctuations in a perturbed ideally-expanded air jet. A non-propagating harmonic perturbation in the density, axial velocity, and pressure is introduced at the inflow with different…

Fluid Dynamics · Physics 2025-01-16 Osama A. Marzouk

It is a deceptively simple question to ask how acoustic disturbances propagate in a non--homogeneous flowing fluid. If the fluid is barotropic and inviscid, and the flow is irrotational (though it may have an arbitrary time dependence),…

General Relativity and Quantum Cosmology · Physics 2016-08-31 Matt Visser

Particulate materials include powders, emulsions, composites, and many others. This is why measuring these has become important for both industry and scientific applications. For industrial applications, the greatest need is to measure…

Statistical Mechanics · Physics 2024-07-10 Paulo S. Piva , Kevish K. Napal , Art L. Gower

This article deals with the approximation of a stochastic partial differential equation (SPDE) via amplitude equations. We consider an SPDE with a cubic nonlinearity perturbed by a general multiplicative noise that preserves the constant…

Dynamical Systems · Mathematics 2019-10-08 Hongbo Fu , Dirk Blömker

We established the propagation equation of acoustical wave in media with the solid/porous media cylindrical boundary and obtained the analytic solution. We suggested the boundary condition on solid-porous media cylindrical boundary. Based…

Materials Science · Physics 2015-11-11 Un-Son Ri , Un-Gyong An , Song-Jin Im

Here, variation of the dispersion characteristics of 3D linearised compressible Navier-Stokes equation with respect to bulk viscosity ratio $\kappa/\mu$, specific heat ratio $\gamma$ and Prandtl number $Pr$ is presented. The 3D compressible…

Fluid Dynamics · Physics 2023-10-02 Swagata Bhaumik , Sawant Omkar Deepak

Controlling systems governed by partial differential equations is an inherently hard problem. Specifically, control of wave dynamics is challenging due to additional physical constraints and intrinsic properties of wave phenomena such as…

Signal Processing · Electrical Eng. & Systems 2023-12-18 Tristan Shah , Feruza Amirkulova , Stas Tiomkin

We consider reaction-diffusion equations that are stochastically forced by a small multiplicative noise term. We show that spectrally stable travelling wave solutions to the deterministic system retain their orbital stability if the…

Analysis of PDEs · Mathematics 2020-03-09 C. H. S. Hamster , H. J. Hupkes

Score-based generative models (SGMs) learn a family of noise-conditional score functions corresponding to the data density perturbed with increasingly large amounts of noise. These perturbed data densities are linked together by the…

Machine Learning · Computer Science 2023-06-16 Chieh-Hsin Lai , Yuhta Takida , Naoki Murata , Toshimitsu Uesaka , Yuki Mitsufuji , Stefano Ermon

We study the coherent propagation and incoherent diffusion of in-plane elastic waves in a two dimensional continuum populated by many, randomly placed and oriented, edge dislocations. Because of the Peierls-Nabarro force the dislocations…

Materials Science · Physics 2020-12-02 Dmitry Churochkin , Fernando Lund

This paper uses asymptotic analysis within the generalized acoustic analogy formulation (Goldstein. J. Fluid Mech 488, pp. 315-333, 2003) to develop a noise prediction model for the peak sound of axisymmetric round jets at subsonic acoustic…

Fluid Dynamics · Physics 2019-07-15 Mohammed Z. Afsar , Adrian Sescu , Stewart. J. Leib

Acoustic wave propagation in a one-dimensional waveguide connected with Helmholtz resonators is studied numerically. Finite amplitude waves and viscous boundary layers are considered. The model consists of two coupled evolution equations: a…

Classical Physics · Physics 2015-06-16 Bruno Lombard , Jean-François Mercier

Stochastic partial differential equations (SPDEs) represent a very active research field with numerous recent developments and breakthrough results. There are several well-established approaches and methods used to construct solutions for…

Probability · Mathematics 2019-08-27 Christian Kuehn , Alexandra Neamtu

The study of sound propagation in a uniform duct having a mean flow has many applications, such as in the design of gas turbines, heating, ventilation and air conditioning ducts, automotive intake and exhaust systems, and in the modeling of…

Computational Engineering, Finance, and Science · Computer Science 2025-03-26 D. Veerababu , Prasanta K. Ghosh

The study points out that the traditional solutions to wave equation of dissipative wave and motion equation of block for a multi-degree-of-freedom mass spring damper system are the possible solutions, which are not necessarily objective…

Classical Physics · Physics 2022-01-21 Peng Shi

We present a novel approach for simulating acoustic (pressure) wave propagation across different media separated by a diffuse interface through the use of a weak compressibility formulation. Our method builds on our previous work on an…

Numerical Analysis · Mathematics 2025-11-11 Abbas Ballout , Oscar A. Marino , Gerasimos Ntoukas , Gonzalo Rubio , Esteban Ferrer

Noise pollution caused by inflow turbulence is a major problem in many applications, such as propellers and fans. Leading edge noise models, e.g., Amiet's model, are widely applied to predict the noise produced by these applications. This…

Fluid Dynamics · Physics 2021-08-05 F. L. dos Santos , L. Botero-Bolívar , C. H. Venner , L. D. de Santana

Webster's horn equation (1919) offers a one-dimensional approximation for low-frequency sound waves along a rigid tube with a variable cross-sectional area. It can be thought as a wave equation with a source term that takes into account the…

Fluid Dynamics · Physics 2013-11-19 Rogério Jorge

Trailing-edge (TE) noise is the main contributor to the acoustic signature of flows over airfoils. It originates from the interaction of turbulent structures in the airfoil boundary layer with the TE. This study experimentally identifies…