Asymptotic based preconditioning technique for low Mach number flows

2003 ◽  
Vol 83 (1) ◽  
pp. 3-25 ◽  
Author(s):  
A. Meister
Keyword(s):  
Mach Number ◽  
Low Mach Number ◽  
Preconditioning Technique

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

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 Turbulent fluxes of entropy and internal energy in temperature stratified flows

2015 ◽  
Vol 81 (5) ◽  
Author(s):  
I. Rogachevskii ◽  
N. Kleeorin
Keyword(s):  
Mach Number ◽  
Internal Energy ◽  
Turbulent Flux ◽  
Stratified Flows ◽  
Fluid Temperature ◽  
Stratified Turbulence ◽  
Convective Flux ◽  
Low Mach Number ◽  
Linear Approach ◽  
The Mean

We derive equations for the mean entropy and the mean internal energy in low-Mach-number temperature stratified turbulence (i.e. for turbulent convection or stably stratified turbulence), and show that turbulent flux of entropy is given by$\boldsymbol{F}_{s}=\overline{{\it\rho}}\,\overline{\boldsymbol{u}s}$, where$\overline{{\it\rho}}$is the mean fluid density,$s$is fluctuation of entropy and overbars denote averaging over an ensemble of turbulent velocity fields,$\boldsymbol{u}$. We demonstrate that the turbulent flux of entropy is different from the turbulent convective flux,$\boldsymbol{F}_{c}=\overline{T}\,\overline{{\it\rho}}\,\overline{\boldsymbol{u}s}$, of the fluid internal energy, where$\overline{T}$is the mean fluid temperature. This turbulent convective flux is well-known in the astrophysical and geophysical literature, and it cannot be used as a turbulent flux in the equation for the mean entropy. This result is exact for low-Mach-number temperature stratified turbulence and is independent of the model used. We also derive equations for the velocity–entropy correlation,$\overline{\boldsymbol{u}s}$, in the limits of small and large Péclet numbers, using the quasi-linear approach and the spectral${\it\tau}$approximation, respectively. This study is important in view of different applications to astrophysical and geophysical temperature stratified turbulence.

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