Matteo Parsani | NASA Langley Research CEnter (original) (raw)
Papers by Matteo Parsani
A Rotated Characteristic Decomposition Technique for High-Order Reconstructions in Multi-dimensions
Journal of Scientific Computing
Compressibility effects on homogeneous isotropic turbulence using Schur decomposition of the velocity gradient tensor
AIAA Scitech 2021 Forum
Fluids
The decomposition of the local motion of a fluid into straining, shearing, and rigid-body rotatio... more The decomposition of the local motion of a fluid into straining, shearing, and rigid-body rotation is examined in this work for a compressible isotropic turbulence by means of direct numerical simulations. The triple decomposition is closely associated with a basic reference frame (BRF), in which the extraction of the biasing effect of shear is maximized. In this study, a new computational and inexpensive procedure is proposed to identify the BRF for a three-dimensional flow field. In addition, the influence of compressibility effects on some statistical properties of the turbulent structures is addressed. The direct numerical simulations are carried out with a Reynolds number that is based on the Taylor micro-scale of Reλ=100 for various turbulent Mach numbers that range from Mat=0.12 to Mat=0.89. The DNS database is generated with an improved seventh-order accurate weighted essentially non-oscillatory scheme to discretize the non-linear advective terms, and an eighth-order accurat...
Skewness effects on the turbulence structure in a high-speed compressible and multi-component inert mixing layers
AIAA AVIATION 2021 FORUM
Scientific Reports
In this study, the generation of airfoil trailing edge broadband noise that arises from the inter... more In this study, the generation of airfoil trailing edge broadband noise that arises from the interaction of turbulent boundary layer with the airfoil trailing edge is investigated. The primary objectives of this work are: (i) to apply a wall-modelled large-eddy simulation (WMLES) approach to predict the flow of air passing a controlled-diffusion blade, and (ii) to study the blade broadband noise that is generated from the interaction of a turbulent boundary layer with a lifting surface trailing edge. This study is carried out for two values of the Mach number, {{\rm Ma}}_{\infty } = 0.3$$Ma∞=0.3 and 0.5, two values of the chord Reynolds number, {{\rm Re}}=8.30 \times 10^5$$Re=8.30×105 and 2.29 \times 10^6$$2.29×106, and two angles of attack, AoA =4^\circ$$=4∘ and 5^\circ$$5∘. To examine the influence of the grid resolution on aerodynamic and aeroacoustic quantities, we compare our results with experimental data available in the literature. We also compare our results with t...
Fluids
In this study, a new set of direct numerical simulations is generated and used to examine the inf... more In this study, a new set of direct numerical simulations is generated and used to examine the influence of mixture composition heterogeneities on the propagation of a premixed iso-octane/air spherical turbulent flame, with a representative chemical description. The dynamic effects of both turbulence and combustion heterogeneities are considered, and their competition is assessed. The results of the turbulent homogeneous case are compared with those of heterogeneous cases which are characterized by multiple stratification length scales and segregation rates in the regime of a wrinkled flame. The comparison reveals that stratification does not alter turbulent flame behaviors such as the preferential alignment of the convex flame front with the direction of the compression. However, we find that the overall flame front propagation is slower in the presence of heterogeneities because of the differential on speed propagation. Furthermore, analysis of different displacement speed componen...
SN Partial Differential Equations and Applications
In this paper, we extend the entropy conservative/stable algorithms presented by Del Rey Fernánde... more In this paper, we extend the entropy conservative/stable algorithms presented by Del Rey Fernández et al. (2019) for the compressible Euler and Navier-Stokes equations on nonconforming p-refined/coarsened curvilinear grids to h/ p refinement/coarsening. The main difficulty in developing nonconforming algorithms is the construction of appropriate coupling procedures across nonconforming interfaces. Here, we utilize a computationally simple and efficient approach based upon using decoupled interpolation operators. The resulting scheme is entropy conservative/stable and element-wise conservative. Numerical simulations of the isentropic vortex and viscous shock propagation confirm the entropy conservation/stability and accuracy properties of the method (achieving ∼ p + 1 convergence), which are comparable to those of the original conforming scheme (Carpenter et al. in
International Journal for Numerical Methods in Fluids
Time integration of Fourier pseudo-spectral DNS is usually performed using the classical fourthor... more Time integration of Fourier pseudo-spectral DNS is usually performed using the classical fourthorder accurate Runge-Kutta method, or other methods of second or third order, with a fixed step size. We investigate the use of higher-order Runge-Kutta pairs and automatic step size control based on local error estimation. We find that the fifth-order accurate Runge-Kutta pair of Bogacki & Shampine gives much greater accuracy at a significantly reduced computational cost. Specifically, we demonstrate speedups of 2x-10x for the same accuracy. Numerical tests (including the Taylor-Green vortex, Rayleigh-Taylor instability, and homogeneous isotropic turbulence) confirm the reliability and efficiency of the method. We also show that adaptive time stepping provides a significant computational advantage for some problems (like the development of a Rayleigh-Taylor instability) without compromising accuracy.
A rezoning-free CESE Scheme for solving the Compressible Euler Equations on Moving Unstructured Meshes
Journal of Computational Physics
Journal of Computational Physics
We present a novel technique for the imposition of non-linear entropy conservative and entropy st... more We present a novel technique for the imposition of non-linear entropy conservative and entropy stable solid wall boundary conditions for the compressible Navier-Stokes equations in the presence of an adiabatic wall, or a wall with a prescribed heat entropy flow. The procedure relies on the formalism and mimetic properties of diagonal-norm, summation-by-parts and simultaneousapproximation-term operators, and is a generalization of previous works on discontinuous interface coupling [1] and solid wall boundary conditions [2]. Using the method of lines, a semi-discrete entropy estimate for the entire domain is obtained when the proposed numerical imposition of boundary conditions are coupled with an entropyconservative or entropy-stable discrete interior operator. The resulting estimate mimics the global entropy estimate obtained at the continuous level. The boundary data at the wall are weakly imposed using a penalty flux approach and a simultaneous-approximation-term technique for both the conservative variables and the gradient of the entropy variables. Discontinuous spectral collocation operators (mass lumped nodal discontinuous Galerkin operators), on high-order unstructured grids, are used for the purpose of demonstrating the robustness and efficacy of the new procedure for weakly enforcing boundary conditions. Numerical simulations confirm the non-linear stability of the proposed technique, with applications to three-dimensional subsonic and supersonic flows. The procedure described is compatible with any diagonal-norm summation-by-parts spatial operator, including finite element, finite difference, finite volume, discontinuous Galerkin, and flux reconstruction schemes.
Positivity-preserving CE/SE schemes for solving the compressible Euler and Navier–Stokes equations on hybrid unstructured meshes
Computer Physics Communications
SIAM Journal on Scientific Computing
Staggered grid, entropy stable discontinuous spectral collocation operators of any order are deve... more Staggered grid, entropy stable discontinuous spectral collocation operators of any order are developed for the compressible Euler and Navier-Stokes equations on unstructured hexahedral elements. This generalization of previous entropy stable spectral collocation work [M. H.
Optimized low-order explicit Runge-Kutta schemes for high- order spectral difference method
Design of optimal explicit linearly stable strong stability preserving Runge-Kutta schemes for the s
Entropy stable spectral collocation element methods for the Navier-Stokes equations
Efficiency of High Order Spectral Element Methods on Petascale Architectures
Lecture Notes in Computer Science, 2016
Towards robust, high order and entropy stable algorithms for the solution of the compressible Navier-Stokes equations on unstructured grids
In practical computation with Runge--Kutta methods, the stage equations are not satisfied exactly... more In practical computation with Runge--Kutta methods, the stage equations are not satisfied exactly, due to roundoff errors, algebraic solver errors, and so forth. We show by example that propagation of such errors within a single step can have catastrophic effects for otherwise practical and well-known methods. We perform a general analysis of internal error propagation, emphasizing that it depends significantly on how the method is implemented. We show that for a fixed method, essentially any set of internal stability polynomials can be obtained by modifying the implementation details. We provide bounds on the internal error amplification constants for some classes of methods with many stages, including strong stability preserving methods and extrapolation methods. These results are used to prove error bounds in the presence of roundoff or other internal errors.
54th AIAA Aerospace Sciences Meeting, 2016
Entropy stable (SS) discontinuous spectral collocation formulations of any order are developed fo... more Entropy stable (SS) discontinuous spectral collocation formulations of any order are developed for the compressible Navier-Stokes equations on hexahedral elements. Recent progress on two complementary efforts is presented. The first effort is a generalization of previous SS spectral collocation work to extend the applicable set of points from tensor product, Legendre-Gauss-Lobatto (LGL) to tensor product Legendre-Gauss (LG) points. The LG and LGL point formulations are compared on a series of test problems. Although being more costly to implement, it is shown that the LG operators are significantly more accurate on comparable grids. Both the LGL and LG operators are of comparable efficiency and robustness, as is demonstrated using test problems for which conventional FEM techniques suffer instability. The second effort generalizes previous SS work to include the possibility of p-refinement at non-conforming interfaces. A generalization of existing entropy stability machinery is developed to accommodate the nuances of fully multi-dimensional summation-by-parts (SBP) operators. The entropy stability of the compressible Euler equations on non-conforming interfaces is demonstrated using the newly developed LG operators and multi-dimensional interface interpolation operators.
A Rotated Characteristic Decomposition Technique for High-Order Reconstructions in Multi-dimensions
Journal of Scientific Computing
Compressibility effects on homogeneous isotropic turbulence using Schur decomposition of the velocity gradient tensor
AIAA Scitech 2021 Forum
Fluids
The decomposition of the local motion of a fluid into straining, shearing, and rigid-body rotatio... more The decomposition of the local motion of a fluid into straining, shearing, and rigid-body rotation is examined in this work for a compressible isotropic turbulence by means of direct numerical simulations. The triple decomposition is closely associated with a basic reference frame (BRF), in which the extraction of the biasing effect of shear is maximized. In this study, a new computational and inexpensive procedure is proposed to identify the BRF for a three-dimensional flow field. In addition, the influence of compressibility effects on some statistical properties of the turbulent structures is addressed. The direct numerical simulations are carried out with a Reynolds number that is based on the Taylor micro-scale of Reλ=100 for various turbulent Mach numbers that range from Mat=0.12 to Mat=0.89. The DNS database is generated with an improved seventh-order accurate weighted essentially non-oscillatory scheme to discretize the non-linear advective terms, and an eighth-order accurat...
Skewness effects on the turbulence structure in a high-speed compressible and multi-component inert mixing layers
AIAA AVIATION 2021 FORUM
Scientific Reports
In this study, the generation of airfoil trailing edge broadband noise that arises from the inter... more In this study, the generation of airfoil trailing edge broadband noise that arises from the interaction of turbulent boundary layer with the airfoil trailing edge is investigated. The primary objectives of this work are: (i) to apply a wall-modelled large-eddy simulation (WMLES) approach to predict the flow of air passing a controlled-diffusion blade, and (ii) to study the blade broadband noise that is generated from the interaction of a turbulent boundary layer with a lifting surface trailing edge. This study is carried out for two values of the Mach number, {{\rm Ma}}_{\infty } = 0.3$$Ma∞=0.3 and 0.5, two values of the chord Reynolds number, {{\rm Re}}=8.30 \times 10^5$$Re=8.30×105 and 2.29 \times 10^6$$2.29×106, and two angles of attack, AoA =4^\circ$$=4∘ and 5^\circ$$5∘. To examine the influence of the grid resolution on aerodynamic and aeroacoustic quantities, we compare our results with experimental data available in the literature. We also compare our results with t...
Fluids
In this study, a new set of direct numerical simulations is generated and used to examine the inf... more In this study, a new set of direct numerical simulations is generated and used to examine the influence of mixture composition heterogeneities on the propagation of a premixed iso-octane/air spherical turbulent flame, with a representative chemical description. The dynamic effects of both turbulence and combustion heterogeneities are considered, and their competition is assessed. The results of the turbulent homogeneous case are compared with those of heterogeneous cases which are characterized by multiple stratification length scales and segregation rates in the regime of a wrinkled flame. The comparison reveals that stratification does not alter turbulent flame behaviors such as the preferential alignment of the convex flame front with the direction of the compression. However, we find that the overall flame front propagation is slower in the presence of heterogeneities because of the differential on speed propagation. Furthermore, analysis of different displacement speed componen...
SN Partial Differential Equations and Applications
In this paper, we extend the entropy conservative/stable algorithms presented by Del Rey Fernánde... more In this paper, we extend the entropy conservative/stable algorithms presented by Del Rey Fernández et al. (2019) for the compressible Euler and Navier-Stokes equations on nonconforming p-refined/coarsened curvilinear grids to h/ p refinement/coarsening. The main difficulty in developing nonconforming algorithms is the construction of appropriate coupling procedures across nonconforming interfaces. Here, we utilize a computationally simple and efficient approach based upon using decoupled interpolation operators. The resulting scheme is entropy conservative/stable and element-wise conservative. Numerical simulations of the isentropic vortex and viscous shock propagation confirm the entropy conservation/stability and accuracy properties of the method (achieving ∼ p + 1 convergence), which are comparable to those of the original conforming scheme (Carpenter et al. in
International Journal for Numerical Methods in Fluids
Time integration of Fourier pseudo-spectral DNS is usually performed using the classical fourthor... more Time integration of Fourier pseudo-spectral DNS is usually performed using the classical fourthorder accurate Runge-Kutta method, or other methods of second or third order, with a fixed step size. We investigate the use of higher-order Runge-Kutta pairs and automatic step size control based on local error estimation. We find that the fifth-order accurate Runge-Kutta pair of Bogacki & Shampine gives much greater accuracy at a significantly reduced computational cost. Specifically, we demonstrate speedups of 2x-10x for the same accuracy. Numerical tests (including the Taylor-Green vortex, Rayleigh-Taylor instability, and homogeneous isotropic turbulence) confirm the reliability and efficiency of the method. We also show that adaptive time stepping provides a significant computational advantage for some problems (like the development of a Rayleigh-Taylor instability) without compromising accuracy.
A rezoning-free CESE Scheme for solving the Compressible Euler Equations on Moving Unstructured Meshes
Journal of Computational Physics
Journal of Computational Physics
We present a novel technique for the imposition of non-linear entropy conservative and entropy st... more We present a novel technique for the imposition of non-linear entropy conservative and entropy stable solid wall boundary conditions for the compressible Navier-Stokes equations in the presence of an adiabatic wall, or a wall with a prescribed heat entropy flow. The procedure relies on the formalism and mimetic properties of diagonal-norm, summation-by-parts and simultaneousapproximation-term operators, and is a generalization of previous works on discontinuous interface coupling [1] and solid wall boundary conditions [2]. Using the method of lines, a semi-discrete entropy estimate for the entire domain is obtained when the proposed numerical imposition of boundary conditions are coupled with an entropyconservative or entropy-stable discrete interior operator. The resulting estimate mimics the global entropy estimate obtained at the continuous level. The boundary data at the wall are weakly imposed using a penalty flux approach and a simultaneous-approximation-term technique for both the conservative variables and the gradient of the entropy variables. Discontinuous spectral collocation operators (mass lumped nodal discontinuous Galerkin operators), on high-order unstructured grids, are used for the purpose of demonstrating the robustness and efficacy of the new procedure for weakly enforcing boundary conditions. Numerical simulations confirm the non-linear stability of the proposed technique, with applications to three-dimensional subsonic and supersonic flows. The procedure described is compatible with any diagonal-norm summation-by-parts spatial operator, including finite element, finite difference, finite volume, discontinuous Galerkin, and flux reconstruction schemes.
Positivity-preserving CE/SE schemes for solving the compressible Euler and Navier–Stokes equations on hybrid unstructured meshes
Computer Physics Communications
SIAM Journal on Scientific Computing
Staggered grid, entropy stable discontinuous spectral collocation operators of any order are deve... more Staggered grid, entropy stable discontinuous spectral collocation operators of any order are developed for the compressible Euler and Navier-Stokes equations on unstructured hexahedral elements. This generalization of previous entropy stable spectral collocation work [M. H.
Optimized low-order explicit Runge-Kutta schemes for high- order spectral difference method
Design of optimal explicit linearly stable strong stability preserving Runge-Kutta schemes for the s
Entropy stable spectral collocation element methods for the Navier-Stokes equations
Efficiency of High Order Spectral Element Methods on Petascale Architectures
Lecture Notes in Computer Science, 2016
Towards robust, high order and entropy stable algorithms for the solution of the compressible Navier-Stokes equations on unstructured grids
In practical computation with Runge--Kutta methods, the stage equations are not satisfied exactly... more In practical computation with Runge--Kutta methods, the stage equations are not satisfied exactly, due to roundoff errors, algebraic solver errors, and so forth. We show by example that propagation of such errors within a single step can have catastrophic effects for otherwise practical and well-known methods. We perform a general analysis of internal error propagation, emphasizing that it depends significantly on how the method is implemented. We show that for a fixed method, essentially any set of internal stability polynomials can be obtained by modifying the implementation details. We provide bounds on the internal error amplification constants for some classes of methods with many stages, including strong stability preserving methods and extrapolation methods. These results are used to prove error bounds in the presence of roundoff or other internal errors.
54th AIAA Aerospace Sciences Meeting, 2016
Entropy stable (SS) discontinuous spectral collocation formulations of any order are developed fo... more Entropy stable (SS) discontinuous spectral collocation formulations of any order are developed for the compressible Navier-Stokes equations on hexahedral elements. Recent progress on two complementary efforts is presented. The first effort is a generalization of previous SS spectral collocation work to extend the applicable set of points from tensor product, Legendre-Gauss-Lobatto (LGL) to tensor product Legendre-Gauss (LG) points. The LG and LGL point formulations are compared on a series of test problems. Although being more costly to implement, it is shown that the LG operators are significantly more accurate on comparable grids. Both the LGL and LG operators are of comparable efficiency and robustness, as is demonstrated using test problems for which conventional FEM techniques suffer instability. The second effort generalizes previous SS work to include the possibility of p-refinement at non-conforming interfaces. A generalization of existing entropy stability machinery is developed to accommodate the nuances of fully multi-dimensional summation-by-parts (SBP) operators. The entropy stability of the compressible Euler equations on non-conforming interfaces is demonstrated using the newly developed LG operators and multi-dimensional interface interpolation operators.