Low Mach Number Magnetic Compression Waves in a Collision-Free Plasma

1961 ◽  
Vol 4 (9) ◽  
pp. 1105 ◽  
Author(s):  
P. L. Auer ◽  
H. Hurwitz ◽  
R. W. Kilb
Keyword(s):  
Mach Number ◽  
Low Mach Number ◽  
Compression Waves ◽  
Magnetic Compression ◽  
Free Plasma

Rankine–Hugoniot relations for shocks with demagnetized ions

2008 ◽  
Vol 74 (2) ◽  
pp. 207-214 ◽  
Author(s):  
M. GEDALIN ◽  
M. BALIKHIN
Keyword(s):  
Mach Number ◽  
Equation Of State ◽  
Compression Ratio ◽  
Collisionless Shock ◽  
Pressure Balance ◽  
Ion Motion ◽  
Low Mach Number ◽  
Balance Condition ◽  
Magnetic Compression ◽  
Approximate Expressions

AbstractThe width of a quasi-perpendicular collisionless shock front is smaller than the convective ion gyroradius so that ions become demagnetized in the ramp. An approach is proposed for derivation of approximate expressions for the magnetic compression ratio and cross-shock potential from the analysis of the ion motion across the ramp and pressure balance condition, without making assumptions about the ion equation of state. The cross-shock potential and magnetic compression ratio are found as functions of the Mach number for low-Mach-number perpendicular shocks.

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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