Correction of Roe's Approximate Riemann Solver for Non-Ideal Gas Equation of State

2002 ◽  
Author(s):  
Jeong-Yeol Choi ◽  
Sejong Oh ◽  
In-Seuck Jeung
Keyword(s):  
Equation Of State ◽  
Ideal Gas ◽  
Riemann Solver ◽  
Approximate Riemann Solver

scholarly journals A Hybrid Real/Ideal Gas Mixture Computational Framework to Capture Wave Propagation in Liquid Rocket Combustion Chamber Conditions

Aerospace ◽  
2021 ◽  
Vol 8 (9) ◽  
pp. 250
Author(s):  
Simone D’Alessandro ◽  
Marco Pizzarelli ◽  
Francesco Nasuti
Keyword(s):  
Wave Propagation ◽  
Equation Of State ◽  
Ideal Gas ◽  
Rocket Engines ◽  
Riemann Solver ◽  
Computational Framework ◽  
Fluid Equation ◽  
Numerical Tools ◽  
Liquid Rocket ◽  
New Equation

The present work focuses on the development of new mathematical and numerical tools to deal with wave propagation problems in a realistic liquid rocket chamber environment. A simplified real fluid equation of state is here derived, starting from the literature. An approximate Riemann solver is then specifically derived for the selected conservation laws and primitive variables. Both the new equation of state and the new Riemann solver are embedded into an in-house one-dimensional CFD solver. The verification and validation of the new code against wave propagation problems are then performed, showing good behavior. Although such problems might be of interest for different applications, the present study is specifically oriented to the low order modeling of high-frequency combustion instability in liquid-propellant rocket engines.

Classical Kinetic Theory

2018 ◽  
Author(s):  
Klaus Morawetz
Keyword(s):  
Kinetic Equation ◽  
Equation Of State ◽  
Mean Field ◽  
Ideal Gas ◽  
Hydrodynamic Equations ◽  
Free Particles ◽  
Internal Mechanism ◽  
The Mean ◽  
Energy Gains ◽  
Non Locality

The classical non-ideal gas shows that the two original concepts of the pressure based of the motion and the forces have eventually developed into drift and dissipation contributions. Collisions of realistic particles are nonlocal and non-instant. A collision delay characterizes the effective duration of collisions, and three displacements, describe its effective non-locality. Consequently, the scattering integral of kinetic equation is nonlocal and non-instant. The non-instant and nonlocal corrections to the scattering integral directly result in the virial corrections to the equation of state. The interaction of particles via long-range potential tails is approximated by a mean field which acts as an external field. The effect of the mean field on free particles is covered by the momentum drift. The effect of the mean field on the colliding pairs causes the momentum and the energy gains which enter the scattering integral and lead to an internal mechanism of energy conversion. The entropy production is shown and the nonequilibrium hydrodynamic equations are derived. Two concepts of quasiparticle, the spectral and the variational one, are explored with the help of the virial of forces.

scholarly journals Approximate Riemann solver for hypervelocity flows

AIAA Journal ◽  
1992 ◽  
Vol 30 (10) ◽  
pp. 2558-2561 ◽  
Author(s):  
P. A. Jacobs
Keyword(s):  
Riemann Solver ◽  
Approximate Riemann Solver ◽  
Hypervelocity Flows

Thermoelasticity

1997 ◽  
Author(s):  
Burak Erman ◽  
James E. Mark
Keyword(s):  
Equation Of State ◽  
Elastic Deformation ◽  
Additional Assumption ◽  
Polymer Network ◽  
Ideal Gas ◽  
Absolute Temperature ◽  
Constant Volume ◽  
Conformational Energy ◽  
Network Chain ◽  
Constant Deformation

The important postulate that intermolecular interactions are independent of extent of deformation leads directly to the conclusion that such interactions cannot contribute to an energy of elastic deformation ΔEel at constant volume. In the earliest theories of rubberlike elasticity, it was additionally assumed that, intramolecular contributions to ΔEel were likewise nil. In this idealization that the total ΔEel is zero, the elastic retractive force exhibited by a deformed polymer network would be entirely entropic in origin. At the molecular level, this would correspond, of course, to assuming all configurations of a network chain to be of exactly the same conformational energy and thus the average configuration to be independent of temperature. Under these circumstances, the dependence of stress on temperature is strikingly simple, as shown, for example, by the equation . . . f* = υkT/V (〈r2〉i/〈r2〉0)(α – α-2) . . . . . . (9.1) . . . that characterizes a polymer network in elongation where, it should be recalled, 〈r2〉i3/2 is proportional to the volume of the network. This additional assumption that 〈r2〉0 is independent of temperature would lead to the prediction that the elastic stress determined at constant volume and elongation α is directly proportional to the absolute temperature. Such network chains would be akin to the particles of an ideal gas, which would obey the equation of state p = nRT(1/V) and thus exhibit a pressure at constant deformation (1/V) likewise directly proportional to the temperature.

A multiphase SPH model based on Roe’s approximate Riemann solver for hydraulic flows with complex interface

2020 ◽  
Vol 365 ◽  
pp. 112999 ◽  
Author(s):  
Zi-Fei Meng ◽  
Ping-Ping Wang ◽  
A-Man Zhang ◽  
Fu-Ren Ming ◽  
Peng-Nan Sun
Keyword(s):  
Riemann Solver ◽  
Approximate Riemann Solver ◽  
Model Based ◽  
Sph Model

The Suliciu approximate Riemann solver is not invariant domain preserving

2019 ◽  
Vol 16 (01) ◽  
pp. 59-72 ◽  
Author(s):  
Jean-Luc Guermond ◽  
Christian Klingenberg ◽  
Bojan Popov ◽  
Ignacio Tomas
Keyword(s):  
Finite Volume ◽  
Riemann Solver ◽  
Approximate Riemann Solver ◽  
Invariant Domain ◽  
First Order

We show that the first-order finite volume technique based on the Suliciu approximate Riemann solver, while being positive, violates the invariant domain properties of the [Formula: see text]-system.

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