arXiv subjects

Alessandro Aiello

Publications and source records attributed to Alessandro Aiello.

4 recordsLinked to original sources

arXiv2026

Pressure-equilibrium-preserving and fully conservative discretization of compressible flow equations for real and thermally perfect gases

Numerical simulations of compressible real-fluid flows are notoriously plagued by spurious pressure oscillations arising in regions of abrupt flow variations. As a possible remedy, several numerical formulations enforce the pressure equilibrium condition for the compressible Euler equations, typically at the cost of spoiling the correct conservation of total energy or by overspecifying the thermodynamical variables. This study proposes for the first time a numerical discretization procedure which is able to discretely preserve the full conservation of the linear invariants (mass, momentum and total energy) and to exactly enforce the pressure equilibrium condition. The method also preserves the conservation of kinetic energy by convection, and is based on the specification of nonlinear numerical fluxes for mass and internal energy which depend on the details of the equation of state. Both thermally perfect and real gases with an arbitrary equation of state are considered, and a simplified approximate pressure equilibrium preserving formulation with excellent performances is also proposed. The effectiveness of the novel formulations is assessed through a series of numerical simulations in supercritical and transcritical conditions with some of the most popular cubic equations of state.

physics.flu-dyn↗

arXiv2026

Impact of Structure-Preserving Discretizations on Compressible Wall-Bounded Turbulence of Thermally Perfect Gases

Direct numerical simulations of compressible turbulent channel flow at supersonic and hypersonic Mach numbers are performed using a thermally perfect gas model for CO$_2$. The objective is to assess the role of structure-preserving discretizations of the convective terms in high-enthalpy regimes, with particular emphasis on entropy conservation, kinetic-energy preservation, and consistency with the thermodynamic closure. The comparative analysis of various formulations examines their impact on robustness, thermodynamic fluctuations, and turbulence statistics across a range of Mach numbers. Differences among formulations are found to originate primarily in the treatment of thermodynamic variables and progressively influence the dynamical fields as compressibility effects intensify. In particular, the coupling between entropy consistency and pressure discretization is shown to affect Reynolds stresses and mean flow properties in high-speed regimes. Overall, the results indicate that consistency between the numerical formulation and the thermodynamic model contributes significantly to the reliable simulation of high-enthalpy compressible turbulence. The study systematically assesses entropy-conservative discretizations for thermally perfect gases in wall-bounded flows and examines their impact on thermodynamic-dynamic coupling at high Mach numbers.

physics.flu-dyn↗

arXiv2025

Entropy conservative discretization of compressible Euler equations with an arbitrary equation of state

This study proposes a novel spatial discretization procedure for the compressible Euler equations which guarantees entropy conservation at a discrete level when an arbitrary equation of state is assumed. The proposed method, based on a locally-conservative discretization, guarantees also the spatial conservation of mass, momentum, and total energy and is kinetic energy-preserving. In order to achieve the entropy-conservation property for an arbitrary non-ideal gas, a general strategy is adopted based on the manipulation of discrete balance equations through the imposition of global entropy conservation and the use of a summation by parts rule. The procedure, which is extended to an arbitrary order of accuracy, conducts to a general form of the internal-energy numerical flux which results in a nonlinear function of thermodynamic and dynamic variables and still admits the mass flux as a residual degree of freedom. The effectiveness of the novel entropy-conservative formulation is demonstrated through numerical tests making use of some of the most popular cubic equations of state.

physics.flu-dyn↗

arXiv2025

Formulation of entropy-conservative discretizations for compressible flows of thermally perfect gases

This study proposes a novel spatial discretization procedure for the compressible Euler equations that guarantees entropy conservation at a discrete level for thermally perfect gases. The procedure is based on a locally conservative formulation, and extends the entropy-conserving schemes to the more realistic case of thermally perfect gases, while still guaranteeing preservation of both linear invariants and kinetic energy. The proposed methodology, which can also be extended to multicomponent gases and to an Asymptotically Entropy-Conservative formulation, shows advantages in terms of accuracy and robustness when compared to existing similar approaches.

physics.flu-dyn↗