Modélisation et simulation des écoulements et transferts thermiques dans les fluides proches du point critique liquide-gaz.
Modélisation thermodynamique des fluides complexes.
Axes de recherche :
________________
Effets thermiques dans les systèmes en rotation (voir les détails sur la page dédiée)
Thermodynamique des mélanges (voir les détails sur la page dédiée)
Publications scientifiques au M2P2
2020
Isabelle Raspo, Evelyne Neau. An empirical correlation for the relative permittivity of liquids in a wide temperature range: application to the modeling of electrolyte systems with a GE/EoS approach.. Fluid Phase Equilibria, Elsevier, 2020, 506, pp.112371. ⟨10.1016/j.fluid.2019.112371⟩. ⟨hal-02325903⟩ Plus de détails...
Relative permittivity, also known as static dielectric constant, is a key property of solvents in electrolyte solutions. It strongly influences the solubility of solutes and, therefore, it can be used as a predictive tool in chemical engineering processes. Relative permittivity also plays an essential role in the modeling of phase equilibria of electrolyte systems, since it is involved in the Debye-Hückel model and in the Mean Spherical Approximation, commonly used to represent long-range interactions between ions. In this paper, we propose a new temperature-dependent correlation for the relative permittivity of liquid water, methanol and ethanol, valid in a wide temperature range, including very high temperatures. Comparison with other literature equations evidenced that the main interest of the proposed correlation is to allow satisfactory predictions of the relative permittivity, not only in the range of validity of other literature models, but also in the high temperature domain, including supercritical temperatures for water. The new correlation is then used with the NRTL-PRA EoS to predict vapor pressure of water with several salts, including single electrolytes and two-salts mixtures; it must be noted that the modeling presented in this work is relevant for any GE/EoS model, since in this case (binary interactions between water and ions being equal to zero), the excess Gibbs energy reduces to the Long-Range term derived from the Pitzer-Debye-Hückel model. A temperature-dependent correction of the solvent relative permittivity is proposed to account for its dependence on ion mole fraction in this Long-Range term. Results thus obtained show that this correction leads to an accurate prediction both: for vapor pressures of aqueous electrolyte solutions in a very wide temperature domain and for the modeling of vapor-liquid equilibria of methanol-water and ethanol-water mixtures with several salts.
Isabelle Raspo, Evelyne Neau. An empirical correlation for the relative permittivity of liquids in a wide temperature range: application to the modeling of electrolyte systems with a GE/EoS approach.. Fluid Phase Equilibria, Elsevier, 2020, 506, pp.112371. ⟨10.1016/j.fluid.2019.112371⟩. ⟨hal-02325903⟩
Isabelle Raspo, Evelyne Neau. An empirical correlation for the relative permittivity of liquids in a wide temperature range: application to the modeling of electrolyte systems with a GE/EoS approach.. Fluid Phase Equilibria, Elsevier, In press. ⟨hal-02325903⟩ Plus de détails...
Relative permittivity, also known as static dielectric constant, is a key property of solvents in electrolyte solutions. It strongly influences the solubility of solutes and, therefore, it can be used as a predictive tool in chemical engineering processes. Relative permittivity also plays an essential role in the modeling of phase equilibria of electrolyte systems, since it is involved in the Debye-Hückel model and in the Mean Spherical Approximation, commonly used to represent long-range interactions between ions. In this paper, we propose a new temperature-dependent correlation for the relative permittivity of liquid water, methanol and ethanol, valid in a wide temperature range, including very high temperatures. Comparison with other literature equations evidenced that the main interest of the proposed correlation is to allow satisfactory predictions of the relative permittivity, not only in the range of validity of other literature models, but also in the high temperature domain, including supercritical temperatures for water. The new correlation is then used with the NRTL-PRA EoS to predict vapor pressure of water with several salts, including single electrolytes and two-salts mixtures; it must be noted that the modeling presented in this work is relevant for any GE/EoS model, since in this case (binary interactions between water and ions being equal to zero), the excess Gibbs energy reduces to the Long-Range term derived from the Pitzer-Debye-Hückel model. A temperature-dependent correction of the solvent relative permittivity is proposed to account for its dependence on ion mole fraction in this Long-Range term. Results thus obtained show that this correction leads to an accurate prediction both: for vapor pressures of aqueous electrolyte solutions in a very wide temperature domain and for the modeling of vapor-liquid equilibria of methanol-water and ethanol-water mixtures with several salts.
Isabelle Raspo, Evelyne Neau. An empirical correlation for the relative permittivity of liquids in a wide temperature range: application to the modeling of electrolyte systems with a GE/EoS approach.. Fluid Phase Equilibria, Elsevier, In press. ⟨hal-02325903⟩
Stéphane Abide, Stéphane Viazzo, Isabelle Raspo, Anthony Randriamampianina. Higher-order compact scheme for high-performance computing of stratified rotating flows. Computers and Fluids, Elsevier, 2018, 174, pp.300-310. ⟨10.1016/j.compfluid.2018.07.016⟩. ⟨hal-02111489⟩ Plus de détails...
To take advantage of modern generation computing hardware, a scalable numerical method, based on higher-order compact scheme, is described to solve rotating stratified flows in cylindrical annular domains. An original approach combining 2d-pencil decomposition and reduced Parallel Diagonal Dominant is proposed to improve the parallelization performance during the computation of Poisson/Helmholtz solvers and time explicit terms. The developed technique is validated with respect to analytical solutions, using the method of manufactured solutions, and available data for two specific configurations. The purpose is to demonstrate its ability to correctly capture the flow characteristics in strato-rotational instability and in baroclinic instability with associated small-scale features. Moreover, this code is found to drastically reduce the huge execution times often preventing detailed numerical investigations of these complex phenomena. Strong scaling test is carried out to assess the performance for up to 1024 cores using grid up to 128 × 568 × 568 in radial, axial and azimuthal directions.
Stéphane Abide, Stéphane Viazzo, Isabelle Raspo, Anthony Randriamampianina. Higher-order compact scheme for high-performance computing of stratified rotating flows. Computers and Fluids, Elsevier, 2018, 174, pp.300-310. ⟨10.1016/j.compfluid.2018.07.016⟩. ⟨hal-02111489⟩
Stéphane Abide, Stéphane Viazzo, Isabelle Raspo, Anthony Randriamampianina. Higher-order compact scheme for high-performance computing of stratified rotating flows. Computers and Fluids, Elsevier, 2018, 174, pp.300-310. ⟨10.1016/j.compfluid.2018.07.016⟩. ⟨hal-01896997⟩ Plus de détails...
Evelyne Neau, Isabelle Raspo, Joan Escandell. The NRTL-PRA group contribution EoS for the simultaneous prediction of LLE, VLE and hE of hydrocarbon mixtures with associating compounds. Fluid Phase Equilibria, Elsevier, 2016, 427, pp.126-142. ⟨10.1016/j.fluid.2016.06.035⟩. ⟨hal-01369874⟩ Plus de détails...
The goal of this study is to propose a modification of the NRTL-PR EoS for the prediction of phase equilibria and excess enthalpies in mixtures containing methanol with hydrocarbons; indeed, with these systems, the original equation is confronted to many difficulties arising from the simultaneous prediction of liquid-liquid equilibria together with vapor-liquid and enthalpy data. For this purpose, an additional term is included in the EoS excess Gibbs energy, , of the Peng-Robinson equation to account for the self-association of methanol. The resulting NRTL-PRA EoS is successfully used for the prediction of both liquid-liquid and vapor-liquid equilibria, as well as excess enthalpies, in mixtures of methanol with hydrocarbons, light gases and associating compounds. Results are comparable to those obtained with other predictive EoS (VTPR and SAFT), but with the main advantage to predict all thermodynamic properties with a simple cubic equation.
Evelyne Neau, Isabelle Raspo, Joan Escandell. The NRTL-PRA group contribution EoS for the simultaneous prediction of LLE, VLE and hE of hydrocarbon mixtures with associating compounds. Fluid Phase Equilibria, Elsevier, 2016, 427, pp.126-142. ⟨10.1016/j.fluid.2016.06.035⟩. ⟨hal-01369874⟩
Manel Wannassi, Isabelle Raspo. Numerical study of non-isothermal adsorption of Naphthalene in supercritical CO2: behavior near critical point. Journal of Supercritical Fluids, Elsevier, 2016, 117, pp.203-218. ⟨10.1016/j.supflu.2016.06.020⟩. ⟨hal-01369830⟩ Plus de détails...
In this study, adsorption in a model binary mixture is investigated near the critical point in a side-heated cavity. The diverging behavior of the equilibrium constant and the Piston effect are taken into account and their influence on the adsorption process is pointed to. The modeling is based on numerical integration of the differential equations, considering the Navier-Stokes equations coupled with the energy and mass diffusion balances. By means of this model, the temperature, density and adsorbed concentration profiles are drawn at different times. Some fundamental concepts about the system’s response to the heating are illustrated. The results reveal that the adsorption process is influenced by the combined effect of several parameters, such as the gravity and the proximity to the critical point. In particular, the adsorbed amount exhibits a reversed dependency on the wall heating very close to the critical point, which confirms the complexity of such a process in binary systems near critical conditions.
Manel Wannassi, Isabelle Raspo. Numerical study of non-isothermal adsorption of Naphthalene in supercritical CO2: behavior near critical point. Journal of Supercritical Fluids, Elsevier, 2016, 117, pp.203-218. ⟨10.1016/j.supflu.2016.06.020⟩. ⟨hal-01369830⟩
Joan Escandell, Isabelle Raspo, Evelyne Neau. Prediction of Solid Polycyclic Aromatic Hydrocarbons Solubility in Water with the NRTL-PR Model. Fluid Phase Equilibria, Elsevier, 2014, 362 (25), pp.87-95. ⟨10.1016/j.fluid.2013.09.009⟩. ⟨hal-00872639⟩ Plus de détails...
The accurate prediction of high pressure phase equilibria is crucial for the development and the design of chemical engineering processes. Among them the modeling of complex systems, such as petroleum fluids with water, has become more and more important with the exploitation of reservoirs in extreme conditions. The aim of this work is to explore the capability of the NRTL-PR model to predict the solubility of solid polycyclic aromatic hydrocarbons in water. For this purpose, we first validate our methodology for fluid phase equilibria predictions of aromatic hydrocarbons and gas (CO2, C2H6) mixtures. Finally, we consider the prediction of the solid solubility of PAH in water, by fitting group parameters either only on SLE data or on both LLE and SLE data of aromatic hydrocarbon-water binary systems.
Joan Escandell, Isabelle Raspo, Evelyne Neau. Prediction of Solid Polycyclic Aromatic Hydrocarbons Solubility in Water with the NRTL-PR Model. Fluid Phase Equilibria, Elsevier, 2014, 362 (25), pp.87-95. ⟨10.1016/j.fluid.2013.09.009⟩. ⟨hal-00872639⟩
Djilali Ameur, Isabelle Raspo. Numerical Simulation of the Poiseuille-Rayleigh-Bénard Instability for a Supercritical Fluid in a Mini-channel. Computational Thermal Sciences, 2013, 5 (2), pp.107-118. ⟨10.1615/ComputThermalScien.2013006169⟩. ⟨hal-00834707⟩ Plus de détails...
The Poiseuille-Rayleigh-Bénard problem, involving the onset of thermoconvective structures in channels heated from below, was the subject of many theoretical, numerical and experimental studies for incompressible flows or perfect gas. However, to the authors' knowledge, this problem was never studied for supercritical fluids. The objective of this paper is to study the influence of the specific properties of such fluids on thermoconvective instability phenomena compared with those observed in the perfect gas case. The effect of the distance to the critical point is also investigated. The numerical approach used is based on the Navier-Stokes equations in the framework of the low Mach number approximation.
Djilali Ameur, Isabelle Raspo. Numerical Simulation of the Poiseuille-Rayleigh-Bénard Instability for a Supercritical Fluid in a Mini-channel. Computational Thermal Sciences, 2013, 5 (2), pp.107-118. ⟨10.1615/ComputThermalScien.2013006169⟩. ⟨hal-00834707⟩
Evelyne Neau, Joan Escandell, Isabelle Raspo. A generalized reference state at constant volume for the prediction of phase equilibria from low pressure model parameters: application to size-asymmetric systems and to the Wong-Sandler mixing rule. Chemical Engineering Science, Elsevier, 2011, 66 (18), pp.4148-4156. ⟨10.1016/j.ces.2011.05.043⟩. ⟨hal-01023163⟩ Plus de détails...
This paper describes an EoS/GE approach based on cubic equations of state making reference to low pressure GE models derived from the lattice fluid theory of Guggenheim. The proposed method does not present the theoretical problems encountered with the literature reference states (infinite pressure of Huron-Vidal, zero pressure of Michelsen and constant packing fraction of Péneloux), namely the description of the alpha function with combinatorial terms derived from both the excess Gibbs energy model and the EoS. The main advantage of the proposed method is to successfully account for the size-asymmetry of mixture components and to improve the results obtained with the Wong-Sandler mixing rule. Comparisons are performed with the MHV1, LCVM and the original Wong-Sandler approach at infinite pressure.
Evelyne Neau, Joan Escandell, Isabelle Raspo. A generalized reference state at constant volume for the prediction of phase equilibria from low pressure model parameters: application to size-asymmetric systems and to the Wong-Sandler mixing rule. Chemical Engineering Science, Elsevier, 2011, 66 (18), pp.4148-4156. ⟨10.1016/j.ces.2011.05.043⟩. ⟨hal-01023163⟩
Most of the models proposed in literature for binary diffusion coefficients of solids in supercritical fluids are restricted to infinite dilution; this can be explained by the fact that most of experimental data are performed in the dilute range. However some industrial processes, such as supercritical fluid separation, operate at finite concentration for complex mixtures. In this case, the concentration dependence of diffusion coefficients must be considered, especially near the upper critical endpoint (UCEP) where a strong decrease of diffusion coefficients was experimentally observed. In order to represent this slowing down, a modified version of the Darken equation was proposed in literature for naphthalene in supercritical carbon dioxide. In this paper, the conditions of application of such a modelling are investigated. In particular, we focus on the order of magnitude of the solubility of the solid and on the vicinity of the critical endpoint. Various equations proposed in literature for the modelling of the infinite dilution diffusion coefficients of the solutes are also compared. Ten binary mixtures of solids with supercritical carbon dioxide were considered for this purpose.
Isabelle Raspo, Christophe Nicolas, Evelyne Neau, Sofiane Meradji. Diffusion coefficients of solids in supercritical carbon dioxide: Modelling of near critical behaviour. Fluid Phase Equilibria, Elsevier, 2008, 263 (2), pp.214-222. ⟨10.1016/j.fluid.2007.09.025⟩. ⟨hal-01139192⟩
Isabelle Raspo, Sofiane Meradji, Bernard Zappoli. Heterogeneous reaction induced by the piston effect in supercritical binary mixtures. Chemical Engineering Science, Elsevier, 2007, 62 (16), pp.4182-4192. ⟨10.1016/j.ces.2007.04.027⟩. ⟨hal-01139223⟩ Plus de détails...
It is now well established that the large compressibility of supercritical fluids is responsible for the strong enhancement of the thermo-acoustic heating, leading to the speeding up of the heat transport thanks to the piston effect instead of the expected slowing down. We show in this paper, through numerical simulations, that the hydrodynamics behavior of supercritical fluids also couples with the critical behavior of the solubility of solids to cause the release of a heterogeneous reaction at solid surfaces in dilute binary supercritical mixtures.
Isabelle Raspo, Sofiane Meradji, Bernard Zappoli. Heterogeneous reaction induced by the piston effect in supercritical binary mixtures. Chemical Engineering Science, Elsevier, 2007, 62 (16), pp.4182-4192. ⟨10.1016/j.ces.2007.04.027⟩. ⟨hal-01139223⟩
Gilbert Accary, Isabelle Raspo. A 3D finite volume method for the prediction of a supercritical fluid buoyant flow in a differentially heated cavity. Computers and Fluids, Elsevier, 2006, 35 (10), pp.1316-1331. ⟨10.1016/j.compfluid.2005.05.004⟩. ⟨hal-00834137⟩ Plus de détails...
This paper describes a three-dimensional finite volume method for the prediction of supercritical fluid buoyant flows in heated enclosures. The space and the time accuracies of the method are checked on an exact analytical solution, and the solver is validated for several benchmark tests for natural convection inside a differentially heated cavity both in the Boussinesq and in the low Mach number approximations. Then, the influence of the linearization of the van der Waals equation of state on the global convergence is discussed. Comparisons, based on the Rayleigh number, between the supercritical fluid and the perfect gas flows in a side heated cavity, show many similarities in the thermal equilibria and considerable differences in the transient behaviours.
Gilbert Accary, Isabelle Raspo. A 3D finite volume method for the prediction of a supercritical fluid buoyant flow in a differentially heated cavity. Computers and Fluids, Elsevier, 2006, 35 (10), pp.1316-1331. ⟨10.1016/j.compfluid.2005.05.004⟩. ⟨hal-00834137⟩
Gilbert Accary, Isabelle Raspo, Patrick Bontoux, Bernard Zappoli. Reverse transition to hydrodynamic stability through the Schwarzschild line in a supercritical fluid layer. Physical Review E : Statistical, Nonlinear, and Soft Matter Physics, American Physical Society, 2005, 72 (3), pp.035301. ⟨10.1103/PhysRevE.72.035301⟩. ⟨hal-00833850⟩ Plus de détails...
We consider a fluid close to its gas-liquid critical point in a bottom-heated cavity. Due to strong density stratification, both the Schwarzschild and the Rayleigh stability criteria are relevant at the same space scale. Taking advantage of the competition between these two limits of the convection-onset criterion, we numerically exhibit striking non-Boussinesq effects: the reverse transition to stability through the Schwarzschild line of a heat diffusing layer subjected to convection, and the convection onset inside a few-millimeters-thick layer according to the Schwarzschild criterion.
Gilbert Accary, Isabelle Raspo, Patrick Bontoux, Bernard Zappoli. Reverse transition to hydrodynamic stability through the Schwarzschild line in a supercritical fluid layer. Physical Review E : Statistical, Nonlinear, and Soft Matter Physics, American Physical Society, 2005, 72 (3), pp.035301. ⟨10.1103/PhysRevE.72.035301⟩. ⟨hal-00833850⟩
Journal: Physical Review E : Statistical, Nonlinear, and Soft Matter Physics
Christophe Nicolas, Evelyne Neau, Sofiane Meradji, Isabelle Raspo. The Sanchez-Lacombe lattice fluid model for the modeling of solids in supercritical fluids. Fluid Phase Equilibria, Elsevier, 2005, 232 (1-2), pp.219-229. ⟨10.1016/j.fluid.2005.03.015⟩. ⟨hal-00846093⟩ Plus de détails...
The Sanchez-Lacombe equation of state is known to describe the thermodynamic properties of molecular fluids of arbitrary size, especially polymer-solvent phase behavior. However, it is rarely used for modeling solid-supercritical fluid equilibria. In this work, it is shown that a proper estimation of the EoS characteristic parameters together with a thermodynamically consistent expression of fugacity coefficients allows a satisfactory correlation of the solubility of solids in the supercritical phase. Binary mixtures containing carbon dioxide, ethane, ethylene and xenon were considered for this purpose. In a first step, the consistency of experimental data was checked using variance analysis. Then, different mixing rules were considered and results compared with those obtained with the Peng-Robinson equation. Finally, the lower and upper boundaries of the solid-liquid-vapor regions (LCEP and UCEP) were also determined and compared with experimental values.
Christophe Nicolas, Evelyne Neau, Sofiane Meradji, Isabelle Raspo. The Sanchez-Lacombe lattice fluid model for the modeling of solids in supercritical fluids. Fluid Phase Equilibria, Elsevier, 2005, 232 (1-2), pp.219-229. ⟨10.1016/j.fluid.2005.03.015⟩. ⟨hal-00846093⟩
Gilbert Accary, Isabelle Raspo, Patrick Bontoux, Bernard Zappoli. Rayleigh-Bénard and Schwarzschild instability in a supercritical fluid. Advances in Space Research, Elsevier, 2005, 36 (1), pp.11-16. ⟨10.1016/j.asr.2005.02.082⟩. ⟨hal-00836317⟩ Plus de détails...
Due to the density stratification, the convection onset criterion in a supercritical fluid layer heated from below includes a stabilizing effect known as the Schwarzschild criterion, which requires an adaptation of the classical low Mach number approximation. We numerically solve the mathematical model describing the motion of a supercritical fluid in the classical Rayleigh-Bénard configuration and we bring to the fore two main events: (i) the reverse transition of an unstable layer to stability without any external intervention; (ii) the convection onset according to the Schwarzschild criterion. In addition, the 3D extension of the study is briefly described.
Gilbert Accary, Isabelle Raspo, Patrick Bontoux, Bernard Zappoli. Rayleigh-Bénard and Schwarzschild instability in a supercritical fluid. Advances in Space Research, Elsevier, 2005, 36 (1), pp.11-16. ⟨10.1016/j.asr.2005.02.082⟩. ⟨hal-00836317⟩
Gilbert Accary, Isabelle Raspo, Patrick Bontoux, Bernard Zappoli. An adaptation of the low Mach number approximation for supercritical fluid buoyant flows. Comptes Rendus Mécanique, Elsevier Masson, 2005, 333 (5), pp.397-404. ⟨10.1016/j.crme.2005.03.004⟩. ⟨hal-00836294⟩ Plus de détails...
This Note describes an acoustic filtering of the equations governing the supercritical fluid buoyant flow driven by a weak heating. The resulting low Mach number approximation takes into account the compressibility of the fluid with respect to the hydrostatic pressure. Using the direct numerical simulation of a supercritical fluid flow in the Rayleigh-Bénard configuration, we show that the density stratification may be taken into account without further numerical effort and is fundamental for the prediction of the convective instability threshold induced by a weak heating.
Gilbert Accary, Isabelle Raspo, Patrick Bontoux, Bernard Zappoli. An adaptation of the low Mach number approximation for supercritical fluid buoyant flows. Comptes Rendus Mécanique, Elsevier Masson, 2005, 333 (5), pp.397-404. ⟨10.1016/j.crme.2005.03.004⟩. ⟨hal-00836294⟩
Gilbert Accary, Isabelle Raspo, Patrick Bontoux, Bernard Zappoli. Stability of a supercritical fluid diffusing layer with mixed boundary conditions. Physics of Fluids, American Institute of Physics, 2005, 17 (10), pp.104105. ⟨10.1063/1.2011469⟩. ⟨hal-00833819⟩ Plus de détails...
We consider a fluid close to its gas-liquid critical point in the Rayleigh-Bénard configuration. Owing to thermoacoustic effects, the bottom heating induces thermal boundary layers along both the lower and the upper horizontal plates. The hydrodynamic stability of these diffusing layers, whose bounding conditions are interchanged, is studied numerically in a two-dimensional (2D) approximation. As far as the convection onset criterion and the critical wave number are concerned, some discrepancies are found between the simulations and the predictions obtained by means of linear analysis. The extension of the study to three-dimensional configurations confirms the validity of the 2D approximation for the analysis of the hydrodynamic stability and shows its inadequacy when the layers become convection dominated.
Gilbert Accary, Isabelle Raspo, Patrick Bontoux, Bernard Zappoli. Stability of a supercritical fluid diffusing layer with mixed boundary conditions. Physics of Fluids, American Institute of Physics, 2005, 17 (10), pp.104105. ⟨10.1063/1.2011469⟩. ⟨hal-00833819⟩
Gilbert Accary, Isabelle Raspo, Patrick Bontoux, Bernard Zappoli. Three-dimensional Rayleigh-Bénard instability in a supercritical fluid. Comptes Rendus Mécanique, Elsevier Masson, 2004, 332 (3), pp.209-216. ⟨10.1016/j.crme.2004.01.009⟩. ⟨hal-00833947⟩ Plus de détails...
This paper describes the unsteady convective flow of a supercritical fluid in the Rayleigh-Bénard configuration. Two-dimensional earlier studies reported fast temperature equilibrium due to the piston effect and the development of a convective instability when the local Rayleigh number exceeds a critical value. In the present work, a high order 3D finite volume method has been developed and optimized, and to our knowledge, we show for the first time a three-dimensional convective instability in a supercritical fluid. Inspecting the time-evolution of temperature field patterns, we exhibit corner effects and a three-dimensional behavior of the flow.
Gilbert Accary, Isabelle Raspo, Patrick Bontoux, Bernard Zappoli. Three-dimensional Rayleigh-Bénard instability in a supercritical fluid. Comptes Rendus Mécanique, Elsevier Masson, 2004, 332 (3), pp.209-216. ⟨10.1016/j.crme.2004.01.009⟩. ⟨hal-00833947⟩
Isabelle Raspo, Bernard Zappoli, Patrick Bontoux. Unsteady two-dimensional convection in a bottom heated supercritical fluid. Comptes Rendus Mécanique, Elsevier Masson, 2004, 332 (5-6), pp.353-360. ⟨10.1016/j.crme.2004.02.003⟩. ⟨hal-00838378⟩ Plus de détails...
We consider a closed Rayleigh-Bénard cell containing a fluid near its gas-liquid critical point (CP). Due to the divergence of several physical properties near the CP, large Rayleigh numbers can be obtained even for small temperature differences. In the convective regime, the heat flow which is obtained on long time scales exhibits some characteristics of that observed in turbulent convection in normally compressible fluids: it is composed of plumes in thermal boundary layers, jets on lateral walls and a large-scale flow. Our results show that, as it is the case in turbulent convection, this large-scale flow can suddenly change its orientation.
Isabelle Raspo, Bernard Zappoli, Patrick Bontoux. Unsteady two-dimensional convection in a bottom heated supercritical fluid. Comptes Rendus Mécanique, Elsevier Masson, 2004, 332 (5-6), pp.353-360. ⟨10.1016/j.crme.2004.02.003⟩. ⟨hal-00838378⟩
Isabelle Raspo, E. Crespo del Arco. Instability in a rotating channel-cavity system with an axial through-flow. International Journal of Heat and Fluid Flow, Elsevier, 2003, 24 (1), pp.41-53. ⟨10.1016/S0142-727X(02)00193-5⟩. ⟨hal-00846032⟩ Plus de détails...
This paper is devoted to the numerical study of time-dependent flows that develop in a Taylor-Couette-like configuration (the outer cylinder exhibiting a side cavity) with a superposed axial through-flow, which is relevant to turbomachinery applications. Depending on the differential rotation rate between the inner cylinder and the cavity walls, the base flow can be either convectively or absolutely unstable, and then wave packets consisting of several small toroidal vortices appear near the inner cylinder and travel downstream. The influence of the different control parameters and of the inlet condition on the occurence of the patterns is analyzed. The flow simulations were obtained by using a spectral approximation coupled with a domain decomposition method for the solution of the axisymmetric time-dependent Navier-Stokes equations in the vorticity-streamfunction formulation.
Isabelle Raspo, E. Crespo del Arco. Instability in a rotating channel-cavity system with an axial through-flow. International Journal of Heat and Fluid Flow, Elsevier, 2003, 24 (1), pp.41-53. ⟨10.1016/S0142-727X(02)00193-5⟩. ⟨hal-00846032⟩
Journal: International Journal of Heat and Fluid Flow
Isabelle Raspo. A direct spectral domain decomposition method for the computation of rotating flows in a T-shape geometry. Computers and Fluids, Elsevier, 2003, 32 (3), pp.431-456. ⟨10.1016/S0045-7930(01)00091-3⟩. ⟨hal-00846076⟩ Plus de détails...
This paper presents a direct domain decomposition method, coupled with a Chebyshev collocation approximation, for solving the incompressible Navier-Stokes equations in the vorticity-streamfunction formulation. The method is based on the influence matrix technique used to treat the lack of vorticity boundary conditions on no-slip walls as well as to enforce the continuity conditions at the interfaces between adjacent subdomains. The multi-domain approach is proposed in order to extend the use of spectral approximations to non-rectangular geometries and singular solutions. It is applied to the computation of a four domain configuration, corresponding to a forced throughflow in a rotating channel-cavity system which is important in air cooling devices and cannot be modeled by single-domain spectral approximations.
Isabelle Raspo. A direct spectral domain decomposition method for the computation of rotating flows in a T-shape geometry. Computers and Fluids, Elsevier, 2003, 32 (3), pp.431-456. ⟨10.1016/S0045-7930(01)00091-3⟩. ⟨hal-00846076⟩
Isabelle Raspo, Sandrine Hugues, Eric Serre, Anthony Randriamampianina, Patrick Bontoux. Spectral projection methods for the simulation of complex three-dimensional rotating flows. Computers and Fluids, Elsevier, 2002, 31 (4-7), pp.745-767. ⟨hal-01023173⟩ Plus de détails...
Isabelle Raspo, Sandrine Hugues, Eric Serre, Anthony Randriamampianina, Patrick Bontoux. Spectral projection methods for the simulation of complex three-dimensional rotating flows. Computers and Fluids, Elsevier, 2002, 31 (4-7), pp.745-767. ⟨hal-01023173⟩
Isabelle Raspo, Sandrine Hugues, Eric Serre, Anthony Randriamampianina, Patrick Bontoux. A spectral projection method for the simulation of complex three-dimensional rotating flows. Computers and Fluids, Elsevier, 2002, 31 (4-7), pp.745-767. ⟨10.1016/S0045-7930(01)00070-6⟩. ⟨hal-00833836⟩ Plus de détails...
In this paper, we present an efficient projection method to solve the three-dimensional time-dependent incompressible Navier-Stokes equations in primitive variables formulation using spectral approximations. This method is based on a modification of the algorithm proposed by Goda [J. Comp. Phys. 30 (1979) 76]. It brings an improvement by introducing a preliminary step for the pressure in order to allow a temporal evolution of the normal pressure gradient at the boundaries. Its efficiency is brought to the fore by comparison with the Goda's algorithm. The modified projection method is then applied to the simulation of complex three-dimensional flows in rotating cavities, involving either a throughflow or a differential rotation.
Isabelle Raspo, Sandrine Hugues, Eric Serre, Anthony Randriamampianina, Patrick Bontoux. A spectral projection method for the simulation of complex three-dimensional rotating flows. Computers and Fluids, Elsevier, 2002, 31 (4-7), pp.745-767. ⟨10.1016/S0045-7930(01)00070-6⟩. ⟨hal-00833836⟩
Eric Serre, Isabelle Raspo, Patrick Bontoux. High order accurate spectral approximation for Navier-Stokes problems. Nonlinear Analysis: Theory, Methods and Applications, Elsevier, 2001, 47 (6), pp.4257-4268. ⟨hal-01023116⟩ Plus de détails...
Eric Serre, Isabelle Raspo, Patrick Bontoux. High order accurate spectral approximation for Navier-Stokes problems. Nonlinear Analysis: Theory, Methods and Applications, Elsevier, 2001, 47 (6), pp.4257-4268. ⟨hal-01023116⟩
Journal: Nonlinear Analysis: Theory, Methods and Applications
Eric Serre, Isabelle Raspo, Patrick Bontoux, Roger Peyret. Spectral solutions of the Navier-Stokes equations for rotating flow,. Journal of Applied Mathematics and Mechanics / Zeitschrift für Angewandte Mathematik und Mechanik, Wiley-VCH Verlag, 2001, 81 (1), pp.533-536. ⟨hal-01023113⟩ Plus de détails...
Eric Serre, Isabelle Raspo, Patrick Bontoux, Roger Peyret. Spectral solutions of the Navier-Stokes equations for rotating flow,. Journal of Applied Mathematics and Mechanics / Zeitschrift für Angewandte Mathematik und Mechanik, Wiley-VCH Verlag, 2001, 81 (1), pp.533-536. ⟨hal-01023113⟩
Journal: Journal of Applied Mathematics and Mechanics / Zeitschrift für Angewandte Mathematik und Mechanik
Eric Serre, Isabelle Raspo, Patrick Bontoux. High-order accurate spectral approximations for Navier-Stokes problems. Nonlinear Analysis: Theory, Methods and Applications, Elsevier, 2001, 47 (6), pp.4257-4268. ⟨10.1016/S0362-546X(01)00541-7⟩. ⟨hal-00835795⟩ Plus de détails...