Assessment of riemann solvers for unsteady one-dimensional inviscid flows of perfect gases

Gottlieb, J. J.; Groth, C. P. T.

doi:10.1016/0021-9991(88)90059-9

Cited by 282 publications

(129 citation statements)

References 18 publications

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“…The equations above can be solved on arbitrary cell types in Cobalt 60 (e.g, hexahedrals, prisms, tetrahdrons). The spatial operator uses the exact Reimann solver of Gottlieb and Groth (1988), least squares gradient calculations using QR factorization to provide second order accuracy in space, and TVD flux limiters to limit extremes at cell faces. A point implicit method using analytic first-order inviscid and viscous Jacobians is used for advancement of the discretized system.…”

Section: Summary Of the Fractional Step Methodsmentioning

confidence: 99%

A New Approach to Prediction of Aircraft Spin

Squires¹

2002

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathenng and maintaining the data needed and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302 Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY)12-12-2002 REPORT TYPE Final Technical Report TITLE AND SUBTITLEA New Approach for Prediction of Aircraft Spin AUTHOR(S)Squires, Kyle D. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)Mechanical Unsteady Reynolds-averaged Navier-Stokes and Detached-Eddy Simulation are used to predict the flow around a forebody cross-section modeled by a rounded-corner square. The inlet velocity is inclined at 10 degrees to the main flow, the configuration modeling the massively separated flow around the forebody of a jet fighter rotating at high angle of attack. Simulations are performed at sub-and super-critical Reynolds numbers, corresponding to either laminar or turbulent boundary layer separation from the forebody. DES predictions show that following flow detachment, a chaotic and three-dimensional wake rapidly develops. The temporal evolution of the streamwise and lateral (side) forces acting on the body exhibit strong modulation due to the spanwise variation of the flow. Grid refinement deepens the structure of the resolved range of turbulent scales, predictions using unstructured meshes are also demonstrated to be equally accurate as those on structured grids. For the super-critical flow, the pressure distribution is close to the measured values, both the streamwise and side forces are in adequate agreement with measurements, and the effect of numerical parameters are well-understood. For the sub-critical flow, DES side-force predictions do not follow the experimental measurements far enough to achieve reversal. Possible causes for the discrepancy are discussed. SUBJECT TERMS

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Section: Summary Of the Fractional Step Methodsmentioning

confidence: 99%

A New Approach to Prediction of Aircraft Spin

Squires¹

2002

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“…(19)) are used in place of the physical fluxes (convective and diffusive) to properly deal with the non-uniqueness of these vectors on the elements interfaces. The inviscid part of the flux is computed via "exact" Riemann solver [13] while the diffusive part as the average of the fluxes computed from neighboring elements.…”

Section: Discontinuous Galerkin Discretizationmentioning

confidence: 99%

“…The adopted DG solver is based on the "exact" Riemann solver [13] and on the BR2 scheme [1] for the computation of the interface convective and diffusive flux vector, respectively. It is well-known that the discretization of multicomponent flow fields has to cope with numerical oscillations that are not encountered with single component flows.…”

Section: Introductionmentioning

confidence: 99%

Discontinuous Galerkin Computation of Gaseous Mixture Coaxial Jets

Franchina¹,

Savini²,

Bassi³

2016

Proceedings of the VII European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016)

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Abstract. A novel approach based upon Discontinuous Galerkin (DG) discretization, applied to the divergence form of the multicomponent Navier-Stokes equations, is here presented and used to compute non reactive turbulent axisymmetric gaseous jets. The original key feature is the use of L 2 -projection form of the (perfect gas) equation of state. This choice mitigates problems typically encountered by the front-capturing schemes in computing multicomponent flow fields, i.e. spurious oscillations across material and contact surfaces where the mixture composition is changing. The solver makes also use of a shock-capturing technique based on artificial dissipation selectively added into the equations and tuned in connection with the magnitude of inviscid residuals of the equations and on suitable coefficients accounting for the variation of the unknown variables within and across grid elements. A simple limiting procedure is introduced in order to avoid the occurrence of unphysical gas properties due to negative and/or greater that one mass fractions values within the domain. The DG code based on the proposed novel technique for multicomponent flow computation is here employed to study the mixing mode and the preferential diffusion mechanism of a mixture jet of helium and carbon dioxide in a surrounding flow of air, both in laminar and turbulent flow regimes. Mass diffusion is modelled by means of Fick's first law and use is made of constant Prandtl and Schmidt numbers in Wilcox's (2008) k − ω model. Third-order accurate results are presented, discussed and compared with the available experimental data. They confirm the possible existence in coaxial jets of different periodic flow structures, greatly affecting mixing rates, and different species diffusive mass fluxes. The relative importance of both phenomena depends on the flow regime and its characteristics. The tests carried out give at the same time indications about the accuracy of the proposed method and its effectiveness in computing complex unsteady flow fields.

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“…The Navier-Stokes equations are discretized on arbitrary grid topologies using a cell-centered finite-volume method. Second-order accuracy in space is achieved using the exact Riemann solver of Gottlieb and Groth [56] and least-squares gradient calculations using QR factorization. To accelerate the solution of the discretized system, a point-implicit method using analytic first-order inviscid and viscous Jacobians is used.…”

Section: Formulationmentioning

confidence: 99%

Transonic Aerodynamic Load Modeling of X-31 Aircraft Pitching Motions

Ghoreyshi¹,

Cummings²,

Ronch³

et al. 2013

AIAA Journal

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The generation of reduced-order models for computing the unsteady and nonlinear aerodynamic loads on an aircraft from pitching motions in the transonic speed range is described. The models considered are based on Duhamel's superposition integral using indicial (step) response functions, Volterra theory using nonlinear kernels, radial basis functions, and a surrogate-based recurrence framework, both using time-history simulations of a training maneuver(s). Results are reported for the X-31 configuration with a sharp leading-edge cranked delta wing geometry, including canard/wing vortex interactions. The validity of the various models studied was assessed by comparison of the model outputs with time-accurate computational-fluid-dynamics simulations of new maneuvers. Overall, the reduced-order models were found to produce accurate results, although a nonlinear model based on indicial functions yielded the best accuracy among all models. This model, along with a time-dependent surrogate approach, helped to produce accurate predictions for a wide range of motions in the transonic speed range. = regression coefficients ε = kriging random process μ = air viscosity; kriging mean value ρ = density, kg∕m 3 σ 2 = covariance τ ij = viscous stress tensor components, Pa Φ i X = radial basis functions ω = circular frequency, rad∕s

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Assessment of riemann solvers for unsteady one-dimensional inviscid flows of perfect gases

Cited by 282 publications

References 18 publications

A New Approach to Prediction of Aircraft Spin

A New Approach to Prediction of Aircraft Spin

Discontinuous Galerkin Computation of Gaseous Mixture Coaxial Jets

Transonic Aerodynamic Load Modeling of X-31 Aircraft Pitching Motions

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