3,511 Hits in 9.7 sec

Calculation of low Mach number acoustics: a comparison of MPV, EIF and linearized Euler equations

Sabine Roller, Thomas Schwartzkopff, Roland Fortenbach, Michael Dumbser, Claus-Dieter Munz
2005 Mathematical Modelling and Numerical Analysis  
The calculation of sound generation and propagation in low Mach number flows requires serious reflections on the characteristics of the underlying equations.  ...  In the latter approach, the non-linear Euler equations are used in a domain as small as possible to cover the sound generation, and the locally linearized Euler equations approximated with a high-order  ...  Since the Mach number occurs as parameter in the equations, the flow variables density, velocity and pressure depend on the Mach number as well.  ... 
doi:10.1051/m2an:2005016 fatcat:wrcpnzm4n5gwnhhghgv4tbb6ry

Multiple spatial scales in engineering and atmospheric low Mach number flows

Rupert Klein
2005 Mathematical Modelling and Numerical Analysis  
In an almost obvious way specializations of this theory to a single spatial scale reproduce automatically the zero Mach number variable density flow equations for the small scales, and the linear acoustic  ...  flow equations through systematic (low Mach number) asymptotics.  ...  The author would like to thank Ann Almgren, Nicola Botta, Julian Hunt, Omar Knio, Andrew Majda, Eileen Mikusky, Claus-Dieter Munz, Antony Owinoh, Vladimir Petukhov, and Stefan Vater, for a wealth of challenging  ... 
doi:10.1051/m2an:2005022 fatcat:dc3qn3qhl5bbbdwx5eem75jrny

The one-dimensional acoustic field in a duct with arbitrary mean axial temperature gradient and mean flow

Jingxuan Li, Aimee S. Morgans
2017 Journal of Sound and Vibration  
The analytical solution reproduces the acoustic field very accurately across a wide range of flow conditions which span both low and moderate-to-high subsonic Mach numbers.  ...  wave number when there is no mean flow and α is the normalised mean density gradient.  ...  solution for linear mean temperature profiles and low Mach number mean flow and Cummings' 366 approximate solution also derived using an adapted WKB approximation.  ... 
doi:10.1016/j.jsv.2017.03.047 fatcat:luq7y4kwabar3ntqa63k25d5qe

Multiple-scale thermo-acoustic stability analysis of a coaxial jet combustor

L. Magri, Y.-C. See, O. Tammisola, M. Ihme, M.P. Juniper
2017 Proceedings of the Combustion Institute  
In this paper, asymptotic multiple-scale methods are used to formulate a mathematically consistent set of thermo-acoustic equations in the low-Mach number limit for linear stability analysis.  ...  The resulting sets of nonlinear equations for hydrodynamics and acoustics are two-way coupled. The coupling strength depends on which multiple scales are used.  ...  Hydrodynamic phenomena: the low-Mach number equations Hydrodynamic phenomena are governed by the continuity, momentum, energy and mixture-fraction low-Mach number equations for constant pressure flames  ... 
doi:10.1016/j.proci.2016.06.009 fatcat:ji44d5lfufe3zptahstouhd6tq

Prediction of Acoustic Response of Tube-rows with Bias-flow Using Linearized Navier-Stokes Equations in Frequency Domain

Wei Na, Susann Boij, Aswathy Surendran, Dong Yang, Aimee Morgans
2019 Proceedings of the ICA congress  
In this paper, heat exchanger with the structure of tube rows with bias flow and possible acoustic interaction at the tube row is studied for the acoustic reflection and transmission.  ...  In the current study, the acoustic response is predicted numerically with the cold flow only and compared to the experimental data, as a preparation for the next study with the hot flow.  ...  ACKNOWLEDGEMENTS This research was financially supported by the Marcus Wallenberg Laboratory for Sound and Vibration Research (MWL) at KTH, Sweden.  ... 
doi:10.18154/rwth-conv-239944 fatcat:fllpbu2buvhcvhc3ykhhmcxolq

Infrasound generation by turbulent convection [article]

M. Akhalkatsi, G. Gogoberidze, P. J. Morrison
2004 arXiv   pre-print
Low frequency acoustic wave generation is studied taking into account the effect of stratification, inhomogeneity of background velocity profile and temperature fluctuations.  ...  It is shown that for the typical parameters of convective storms the dipole radiation related to temperature inhomogeneities is at least of the same order as radiation of Lighthill's quadrupole source.  ...  Acknowledgments Authors are grateful to Ming Xue for valuable help.  ... 
arXiv:astro-ph/0409367v1 fatcat:zwawu3stebdyrpbi3ye7il65u4

An Analysis Of Acoustic Function And Navier-Stokes Equations In Aerodynamic

Hnin Hnin Kyi, Khaing Khaing Aye
2008 Zenodo  
Acoustic velocity relates with velocity and Mach number. Mach number relates again acoustic stability or instability condition.  ...  Mach number plays an important role in growth or decay in energy system. Acoustic is a function of temperature and temperature is directly proportional to pressure.  ...  Zaw Min Aung (Rector (MTU)) for his valuable contributions to this project and abiding interest in acoustic stability research is most gratefully acknowledged.  ... 
doi:10.5281/zenodo.1082768 fatcat:xilgw2dh2jex7g3j5voyz5ytrm

Nonreflecting boundary conditions based on nonlinear multidimensional characteristics

Qianlong Liu, Oleg V. Vasilyev
2010 International Journal for Numerical Methods in Fluids  
However, for the nonlinear multidimensional flows, it generates strong spurious wave reflections of pressure, density, velocity, and temperature from the artificial boundaries, especially for the outflow  ...  Nonlinear characteristic boundary conditions based on nonlinear multidimensional characteristics are proposed for 2-and 3-D compressible Navier-Stokes equations with/without scalar transport equations.  ...  ACKNOWLEDGEMENTS Partial support for this work was provided by the National Aeronautics and Space Administration (NASA) under grant No.  ... 
doi:10.1002/fld.2011 fatcat:sgcdjhhjg5hohhwuwdiujnllzi

Low Mach Number Modeling of Type Ia Supernovae. I. Hydrodynamics

A. S. Almgren, J. B. Bell, C. A. Rendleman, M. Zingale
2006 Astrophysical Journal  
For low Mach number flows with potentially finite amplitude variations in density and temperature, the low Mach number model overcomes the limitations of each of the more traditional models and can serve  ...  Our equation set is derived from the fully compressible equations using low Mach number asymptotics, but without any restriction on the size of perturbations in density or temperature.  ...  We show that the low Mach number algorithm works well for very low Mach number flows, with validation presented to Mach numbers $0.2.  ... 
doi:10.1086/498426 fatcat:pybmrvt7afawnlh2itavombh2q

Fully-coupled pressure-based finite-volume framework for the simulation of fluid flows at all speeds in complex geometries

Cheng-Nian Xiao, Fabian Denner, Berend G.M. van Wachem
2017 Journal of Computational Physics  
an energy equation discretized in conservative form that ensures an accurate prediction of temperature and Mach number across strong shocks.  ...  Starting from an existing pressure-based and fully-coupled formulation for the solution of incompressible flow equations, the additional implementation of pressure-density-energy coupling as well as shock-capturing  ...  Acknowledgements The authors are grateful for the financial support provided by Shell Corporation and by the Engineering and Physical Sciences Research Council (EPSRC) through grant No. EP/M021556/1.  ... 
doi:10.1016/ fatcat:6tboq5dnwvcbnpmdv5eknxunm4

A Low Mach Number Model for Moist Atmospheric Flows

Max Duarte, Ann S. Almgren, John B. Bell
2015 Journal of the Atmospheric Sciences  
We numerically assess the validity of the low Mach number approximation for moist atmospheric flows by contrasting the low Mach number solution to reference solutions computed with a fully compressible  ...  We introduce a low Mach number model for moist atmospheric flows that accurately incorporates reversible moist processes in flows whose features of interest occur on advective rather than acoustic time  ...  Department of Energy, Office of Science, Office of Advanced Scientific Computing Research, Applied Mathematics program under contract number DE-AC02005CH11231.  ... 
doi:10.1175/jas-d-14-0248.1 fatcat:i7iej52vdrdwfpbsce3cbezkdu

High order numerical simulation of aeolian tones

Bernhard Müller
2008 Computers & Fluids  
High order finite difference methods have been constructed to be strictly stable for linear hyperbolic and parabolic problems.  ...  The difference operators have been extended from the Euler to the Navier-Stokes equations for computational aeroacoustics.  ...  Acknowledgements The Navier-Stokes code has been parallelized by my colleague Jarmo Rantakokko using OpenMP for a parallel computer with shared memory. A Sun Fire 15k  ... 
doi:10.1016/j.compfluid.2007.02.008 fatcat:pv5p4olwxraxvbf53svg77gjca

Page 688 of Mathematical Reviews Vol. 30, Issue 4 [page]

1965 Mathematical Reviews  
In the case of the sphere for high Mach number flows at low Reynolds number, the drag coefficient C) compares favour- ably with experimentally [cf.  ...  The problem of low-density, high-speed flow in the transition region is studied with the help of first- and second-order boundary-layer equations based on deriva- tions by Van Dyke [Hypersonic flow research  ... 

A unified algorithm for interfacial flows with incompressible and compressible fluids [article]

Fabian Denner, Berend van Wachem
2022 arXiv   pre-print
The majority of available numerical algorithms for interfacial two-phase flows either treat both fluid phases as incompressible (constant density) or treat both phases as compressible (variable density  ...  We propose a numerical algorithm that can simulate interfacial flows in all Mach number regimes, ranging from M=0 to M > 1, including interfacial flows in which compressible and incompressible fluids interact  ...  Acknowledgements This research was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation), grant numbers 420239128 and 447633787.  ... 
arXiv:2201.07447v1 fatcat:ndodlc7rxzcaba3ckg3vyayasq

A semi-analytical solution for acoustic wave propogation in varying area ducts with mean flow

Saikumar Reddy Yeddula, Aimee Morgans
2019 Proceedings of the ICA congress  
When the limiting frequency criteria are satisfied, the semi-analytical solution agrees well with the 2LEE results at even flow Mach-numbers around 0.5.  ...  A second order differential equation (ODE) for acoustic pressure is derived from the linearised Euler equations in the frequency domain, by neglecting the communication between acoustic and entropy disturbances  ...  ACKNOWLEDGEMENTS The authors would like to acknowledge the European Research Council (ERC) Consolidator Grant AFIRMA-TIVE (2018-2023) for supporting the current research.  ... 
doi:10.18154/rwth-conv-239453 fatcat:dvxkpca3x5cb5bj3xaii5psy5e
« Previous Showing results 1 — 15 out of 3,511 results