scholarly journals Computation of non-isothermal and compressible low Mach number gas flows by fully explicit scheme using control method for speed of sound

2019 ◽  
Vol 6 (1) ◽  
pp. 11-20
Author(s):  
Daisuke Toriu ◽  
Satoru Ushijima
Keyword(s):  
Mach Number ◽  
Speed Of Sound ◽  
Control Method ◽  
Explicit Scheme ◽  
Gas Flows ◽  
Low Mach Number

scholarly journals An interface capturing method for liquid-gas flows at low-Mach number

2021 ◽  
Vol 216 ◽  
pp. 104789
Author(s):  
Federico Dalla Barba ◽  
Nicoló Scapin ◽  
Andreas D. Demou ◽  
Marco E. Rosti ◽  
Francesco Picano ◽  
...  
Keyword(s):  
Mach Number ◽  
Gas Flows ◽  
Low Mach Number ◽  
Interface Capturing

scholarly journals Semiconservative reduced speed of sound technique for low Mach number flows with large density variations

2019 ◽  
Vol 622 ◽  
pp. A157 ◽  
Author(s):  
H. Iijima ◽  
H. Hotta ◽  
S. Imada
Keyword(s):  
Mach Number ◽  
Speed Of Sound ◽  
Mass Density ◽  
Low Mach Number ◽  
Efficient Simulation ◽  
Large Density ◽  
Background Density ◽  
Density Perturbations ◽  
Volume Method ◽  
Numerical Domain

Context. The reduced speed of sound technique (RSST) has been used for efficient simulation of low Mach number flows in solar and stellar convection zones. The basic RSST equations are hyperbolic and are suitable for parallel computation by domain decomposition. The application of RSST is limited to cases in which density perturbations are much smaller than the background density. In addition, nonconservative variables are required to be evolved using this method, which is not suitable in cases where discontinuities such as shock waves coexist in a single numerical domain. Aims. In this study, we suggest a new semiconservative formulation of the RSST that can be applied to low Mach number flows with large density variations. Methods. We derive the wave speed of the original and newly suggested methods to clarify that these methods can reduce the speed of sound without affecting the entropy wave. The equations are implemented using the finite volume method. Several numerical tests are carried out to verify the suggested methods. Results. The analysis and numerical results show that the original RSST is not applicable when mass density variations are large. In contrast, the newly suggested methods are found to be efficient in such cases. We also suggest variants of the RSST that conserve momentum in the machine precision. The newly suggested variants are formulated as semiconservative equations, which reduce to the conservative form of the Euler equations when the speed of sound is not reduced. This property is advantageous when both high and low Mach number regions are included in the numerical domain. Conclusions. The newly suggested forms of RSST can be applied to a wider range of low Mach number flows.

scholarly journals A numerical method for the simulation of low Mach number liquid–gas flows

2010 ◽  
Vol 229 (23) ◽  
pp. 8844-8867 ◽  
Author(s):  
V. Daru ◽  
P. Le Quéré ◽  
M.-C. Duluc ◽  
O. Le Maître
Keyword(s):  
Mach Number ◽  
Numerical Method ◽  
Gas Flows ◽  
Low Mach Number

Flow Excited Resonance of a Confined Shallow Cavity in Low Mach Number Flow and Its Control

2002 ◽  
Author(s):  
S. Ziada ◽  
H. Ng ◽  
C. Blake
Keyword(s):  
Mach Number ◽  
Shear Layer ◽  
Control Method ◽  
Acoustic Resonance ◽  
Synthetic Jet ◽  
Low Mach Number ◽  
Acoustic Modes ◽  
Shallow Cavities ◽  
Number Flow ◽  
Low Mach Number Flow

Shallow cavities exposed to unbounded, low Mach number flow are generally weak aeroacoustic sources because their acoustic modes are heavily damped. This paper focuses on a cavity mounted on the wall of a duct to investigate the effect of “confinement”, i.e. solid boundaries close to the cavity, on the aeroacoustic response of shallow cavities in low Mach number flow (M < 0.3). It is found that the transverse acoustic modes of the duct-cavity combination are excited by the higher order modes of the cavity shear layer oscillations. The nature of the excitation mechanism as well as the effects of the cavity and duct dimensions are investigated by means of measurements of the amplitude and phase distributions of the acoustic pressure, complemented with flow visualization of the cavity shear layer oscillation. A method to predict the onset of resonance is also suggested. It is also shown that the acoustic resonance is effectively suppressed by a feedback control method, which generates a synthetic jet acting at the cavity upstream corner. The effect of the phase and gain of the controller transfer function is studied in some detail.

scholarly journals Low Mach number fluctuating hydrodynamics for electrolytes

2016 ◽  
Vol 1 (7) ◽  
Author(s):  
Jean-Philippe Péraud ◽  
Andy Nonaka ◽  
Anuj Chaudhri ◽  
John B. Bell ◽  
Aleksandar Donev ◽  
...  
Keyword(s):  
Mach Number ◽  
Fluctuating Hydrodynamics ◽  
Low Mach Number
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