About

Luca Massa is an Associate Professor in the Kevin T. Crofton Department of Aerospace and Ocean Engineering at Virginia Tech. He holds a Ph.D. in Aerospace Engineering from Mississippi State University and a B.S. in Mechanical Engineering from Politecnico di Bari, Italy. His research expertise includes numerical methods, combustion, fluid dynamics, plasma dynamics, and hypersonics. Dr. Massa has held positions as a Research Scientist at the University of Illinois and the University of Texas at Arlington, as well as a Visiting Professor at Clemson University. Since 2016, he has been an assistant professor at Virginia Tech, where he continues to contribute to the fields of aerospace and ocean engineering.

Research topics

• Physics
• Mechanics
• Computer Science
• Materials science
• Aerospace engineering
• Chemistry
• Mathematical analysis
• Classical mechanics
• Mathematics
• Engineering

Selected publications

• Mechanistic Model of Polypropylene and Polystyrene Solid Fuel Combustion for Supersonic Propulsion

  2026-01-08

  articleSenior author

  This paper presents a novel mechanistic model for the thermal decomposition and combustion of solid polymer fuels, specifically polypropylene and polystyrene, developed using the method of moments. The model captures the complex multiphase interactions within the thin foam-like decomposition layer at the polymer surface, coupling volatile production in the condensed phase with gas-phase oxidation through a foam-layer formulation. Key polymer pyrolysis reactions, including chain fission, radical recombination, hydrogen abstraction, and $\beta$-scission, are represented in a reduced-order moment framework, enabling efficient yet detailed simulation of molecular weight evolution and volatile species formation. Gas-phase combustion of volatiles is modeled using a detailed styrene and propylene oxidation mechanism validated against shock tube ignition delay data. Two momentum coupling models within the foam layer are explored, with the bubble-driven flow model showing improved agreement with experimental regression rates and flame stand-off distances measured in counterflow diffusion flames. The coupled pyrolysis-combustion model demonstrates excellent agreement with pyrolysis experiments and significantly enhanced predictive capability for burn rates and flame structure compared to prior global models. Sensitivity analyses highlight the influence of foam parameters on combustion performance. This integrated framework advances the understanding and predictive modeling of solid polymer fuel combustion for supersonic propulsion applications.

  PublisherDOI

• Unsteady Metric-Based Adaptation via Koopman Expansion

  AIAA Journal · 2026-03-16

  article

  Unsteady flowfields are integral to high-speed applications, demanding precise modeling to accurately characterize their dynamic features. The simulation of unsteady supersonic and hypersonic flows is inherently computationally expensive, necessitating a highly refined mesh to capture these dynamic effects. While anisotropic metric-based adaptive mesh refinement has proven effective in achieving accuracy with much less complexity, current algorithms are primarily tailored for steady flowfields. This paper presents a novel approach to address the challenges of anisotropic grid adaptation of unsteady flows by leveraging a data-driven technique called dynamic mode decomposition (DMD). DMD has proven to be a powerful tool to model complex nonlinear flows, given its links to the Koopman operator and also its easy mathematical implementation. This research proposes the integration of DMD into the process of anisotropic grid adaptation to dynamically adjust the mesh in response to evolving flow features. The effectiveness of the proposed approach is demonstrated through numerical experiments on representative unsteady flow configurations, such as a cylinder in a subsonic flow and an oscillating cylinder in a supersonic channel flow. Results indicate that the incorporation of DMD enables an accurate representation of unsteady flow dynamics independently of the remeshing interval. Computational fluid dynamics results obtained with the dynamic anisotropic mesh adaptation achieved a fourfold reduction in drag error compared to static meshing methods.

  PublisherDOI

• Geometry and Fuel Effects on Solid Fuel Combustion in Scramjet Conditions

  2025-01-03 · 1 citations

  article1st authorCorresponding

  The contributions of regressing walls and fuel chemical composition to solid fuel combustion are investigated numerically and validated against new experimental data in a solid fuel, deep cavity scramjet geometry. Large eddy simulations discretized with discontinuous Galerkin (DG) finite elements are solved with a flamelet manifold approach in three-dimensions. A multi-phase model that incorporated thermal decomposition inside the foam layer to aid in pyrolysis is coupled with stagnation flow flames to determine the combustion manifold and regression rate. The approach accurately models small scale experiments of convective burning over solid fuel samples. The inclusion of the manifold into the DG code features two innovations: a polynomial fitting of the pressure variations to reduce the interpolation dimensions and the use of the coefficient of determination to include non-monotonic manifolds in DG schemes. Model validation was performed using pressure and averaged regression rate data which both showed strong agreement with experimental results. Manifold solutions are compared to detailed kinetics for a variety of test-cases in order to determine how well the simplified manifold models represent fuel variations in the scramjet. Regressed surface are evaluated using a new Bspline algorithm to reconstruct the surface along with an hyper-elasticity approach to deform the volume grid while maintaining a refined boundary layer point distribution. Good agreement versus the PMMA results are obtained and the effect of reduction in pressure losses on the thrust is discussed.

  PublisherDOI

• Detailed Modeling of Plasma-Assisted Ignition in a Scramjet Cavity

  2025-01-03

  articleSenior author

  A multi-scale model for plasma-assisted combustion is used to study how a scramjet cavity affects a supersonic flow. This study examines how turbulence using an LES EDC (Eddy Dissipation Concept) model interacts with a plasma generated by two electrodes in a scramjet cavity with a supersonic freestream. A validation test is done on the EDC implementation by simulating a methane-air flame. Good agreement is shown between the EDC model and the experiment. We develop a code that incorporates the LES-EDC model coupling with a plasma model semiempirical plasma model and a more detailed drift-diffusion plasma model. Simulations are conducted to show how the scramjet cavity affects the supersonic air entering the cavity and injecting a hydrogen jet.

  PublisherDOI

• Effect of Regressing Walls and Skin Friction on Supersonic Solid Fuel Combustion

  Journal of Propulsion and Power · 2025-11-03 · 1 citations

  articleSenior author

  Solid fuel combustors feature a time-deforming geometry that supports changes in the wall boundary layers. The optimization of the fuel chemistry and combustor geometry requires an understanding of the burn rate response to changes in the boundary-layer characteristics. One key metric of cavity-stabilized flames for supersonic combustion is the wall shear stress and its effect on the burn rate near the aft end of the cavity. A new flamelet model based on the ignition of stagnation-point flames against fuel surfaces is presented that is significantly more accurate than previous models based on flamelet extinction. An erosive burn rate response model is designed and validated against experiments for three stages of deformation using large-eddy simulations. This model approximates turbulent eddy penetration toward the walls using a mixing length damping approach. The erosive model provides much improved regression rates in the late stages of burning, when the combustor operates in scramjet mode, demonstrating the importance of shear stress to the burn rate response. Key to the success of the model is simulating the relaminarization supported by favorable pressure gradients.

  PublisherDOI

• Erosive Effects and Melt Layer Stability in Solid Fuel Scramjets

  2025-07-16

  article1st authorCorresponding

  One of the most fundamental issues of hypersonic vehicle design is the requirement for propulsion, engine-airframe integration: systems are so tightly coupled the aero and propulsion cannot be separated from each other. The tight integration of engine and airframe in scramjets can be facilitated by solid fuel walls that reduce the heat losses of the highly integrated combustion chamber and provide a simple valve-free mechanism to produce thrust. The main drawback of solid fuels wall is the change in geometry during flight that leads to variations of the combustion efficiency. The present computational investigation aims at improving the state of the understanding of the interactions between solid fuel walls and working fluid with emphasis on the processes that control pyrolization and wall regression. The most important issue in modelling the regression rate is to approximate the effect of the shear stress on the fuel burn rate laws. This is known as erosive burning in solid propellant literature. In the present work, we evaluate the effect of shear stress on the burn rate and propose a computational model of its physics based mixing length damping near the wall.

  PublisherDOI

• On electrode placement in plasma-assisted ignition of a scramjet flame-holder

  Combustion and Flame · 2025-08-28 · 2 citations

  articleOpen accessSenior authorCorresponding

  A multi-scale model for plasma-assisted combustion is developed to investigate how the location of the electrodes in the cavity affects the ignition of supersonic flows in nanosecond repetitive pulse discharges. A new approach to plasma-fluid coupling is investigated that relies on solving the detailed plasma and photon transport equations on a near-electrode block partition of the overall mesh during the pulse and synchronizing the thermochemical balances with the reactive-fluid mesh by interpolation. The approach reproduces experimental observations of assisted ignition: the formation of trailing-edge flames in high-enthalpy conditions, the formation of localized ignition kernels near the cathode for medium-enthalpy conditions, and the presence of a distributed region of elevated OH mass fraction for conditions leading to no ignition. The approach matches the experimental measurement of plasma-energy coupling. The analysis emphasizes the significance of fluid strain rate in plasma-fluid coupling. The location of the electrode is found to affect ignition by supporting a larger radical turnover by plasma when the electrodes are placed in regions of lower strain, leading to a thicker reaction region. Novelty, Significance, and Contributions : A novel computational approach to plasma-gas coupling is developed and validated. This approach was applied to investigate the influence of strain rate on the focusing of pre-ionization electrons in the low-shear region of cavity stabilizers. The authors identify a correlation between strain rate and radical turnover number. This study led to the determination of the contribution of electrode placement to the efficacy of plasma actuation in supersonic flame-holders. The importance of the cathode location to supersonic ignition is investigated for the first time in detail. This research presents a significant advancement of previously published works: it models photoionization from first principles and includes the gas-plasma interactions in a three-dimensional turbulent flow.

  PublisherDOI

• Teaching thermo-chemical equilibrium using a MATLAB algorithm

  2025-02-27 · 1 citations

  articleOpen access1st authorCorresponding

  The chemical equilibrium model is significantly more accurate than the perfect gas model when calculating constant heat release as pertains to systems taught in courses within the thermo-fluid area of mechanical and aerospace engineering curricula, including thermodynamics, propulsion, and internal combustion engines. This paper presents a novel approach to teaching chemical equilibrium using a method based on matrix factorization. The advantages of the present approach, when compared to previous algorithms based on constrained optimization, are the straightforward formulation and the ease of implementation in MATLAB. The formulation is straightforward because it emphasizes that the equilibrium composition is based on thermodynamic considerations and thus, does not require knowledge of reaction paths. The implementation is simple because it avoids summation over chemical elements and species in favor of a singular value decomposition and matrix-vector multiplications. The teaching effectiveness of the new formulation is tested using an in-class survey. Based on the students’ feedback, we find that this module proved beneficial towards developing a sound understanding of the topic.

  PublisherOA PDFDOI

• Flow Characteristics in an Optically Accessible Solid Fuel Scramjet

  Journal of Propulsion and Power · 2025-02-03 · 3 citations

  article

  A direct connect, optically accessible combustor was used to reveal flow characteristics inside a reacting solid fuel supersonic combustor with air inlet total pressure of 12.9 atm and total temperature of 1225 K using polymethyl-methacrylate fuel grains. Flow visualization techniques such as shadowgraph, chemiluminescence, and high-speed imaging/planar pyrometry were used to characterize the flowfield, which has not been previously reported on for a solid fuel scramjet. Shadowgraphs revealed the role of the cavity flameholder geometry in defining the flowfield. Large length to depth ratios force the recirculation zone to expand into the core flow, causing flow biasing. Small length to depth ratios allow the recirculation zone to be fully contained within the flameholding cavity. [Formula: see text] chemiluminescence shows that most of the heat release takes place in the cavity flameholder favoring the upstream region near the air inlet. Both the flow visualization and measured fuel regression rates indicate that the majority of the fuel that contributes to combustion pyrolyzes from the converging angle of the flameholding cavity. Fuel regression rates decrease as fuel is consumed and the cross sectional area of the flowpath increases, consistent with historical observation of solid fuel regression rate dependency on air mass flux.

  PublisherDOI

• Modeling Mismatched Materials in Heat Flux Reconstruction with Embedded Sensors

  2025-07-16 · 1 citations

  articleSenior author

  Creating heat flux maps is one of the major data reduction tasks of ground-test hypersonic facilities. The ability to embed multiple high-frequency sensing elements improves the perfor- mance of Schmidt-Bolter gauges when there is significant lateral heat flux, i.e., close to the leading edge of fin elements and wings. Hypersonic flow heat transfer tests with mismatched materials were conducted in a Mach 6 quiet facility to demonstrate the ability of embedded- sensor gauges to measure the vector heat flux. A novel algorithm to reconstruct the thermal field in the gauge and extract both the lateral and normal components of the heat flux vector is discussed. This work presents two main innovations: i) a least squares approach to balance the impulse response for mismatched gauge materials, 2) an advanced regularization approach based on cross validation of samples distributed in a K-folded time-series. The reconstruction approach is verified using virtual tests carried out with finite element simulations on gauges with different distributions of epoxy and metal. Validation is carried out on hypersonic wind tunnel tests with both matched and mismatched gauge-article materials. The main findings of this research are that the intergauge heat flux that arises due to mismatched materials is important and accounts for more than 20% of the normal heat flux and that the novel approach to regularization is able to resolve such a lateral heat flux in space-time bases with few sensors (number of spatial splines greater or equal than number of sensors).

  PublisherDOI

Frequent coauthors

• T. L. Jackson

  26 shared

• J. Buckmaster

  18 shared

• Monika Chauhan

  Indian Institute of Information Technology Design and Manufacturing Jabalpur

  14 shared

• Jonathan B. Freund

  12 shared

• Frank Lu

  10 shared

• Nhat Minh Nguyen

  9 shared

• Henry Pace

  Virginia Tech

  8 shared

• Joanna M. Austin

  California Institute of Technology

  6 shared

Labs

• Aerospace & Ocean EngineeringPI