About

Liselle Joseph is an Assistant Professor in the Kevin T. Crofton Department of Aerospace and Ocean Engineering at Virginia Tech, holding a Ph.D. in Aerospace Engineering from Virginia Tech earned in 2017. Her educational background includes a B.S. and M.S. in Aerospace Engineering from Virginia Tech, completed in 2011 and 2014 respectively. Her research expertise encompasses hypersonic flows, experimentation and simulations, turbulent flows, boundary layer theory, and experimental design and instrumentation. She is involved in the PHASE Research Group and teaches courses such as Aerodynamics & Compressibility (AOE 3114). Her professional history includes roles as a Senior Scientist at Spectral Sciences Inc. and a Senior Aero/Thermal Engineer at Pratt & Whitney Compression Systems Aerodynamics, prior to her current academic appointment. Her research focuses on advanced diagnostics and experimental testing within aerodynamics and hydrodynamics, contributing to the understanding of complex flow phenomena.

Research topics

• Physics
• Computer Science
• Mechanics
• Structural engineering
• Mathematics
• Mechanical engineering
• Engineering
• Optics
• Geology
• Aerospace engineering
• Geometry
• Simulation

Selected publications

• Characterizing the Mach 6 Flow of Virginia Tech's Hypersonic Wind Tunnel

  2026-01-08

  articleSenior author

  A recommissioning and characterization campaign is currently underway for Virginia Tech's hypersonic wind tunnel to assess its operational capabilities. The facility operates between Mach 2 and Mach 7, and has been used for basic aerodynamic measurements and advanced instrumentation development. This study focuses on characterizing the tunnel's Mach 6 nozzle's full range of capabilities, including the operational range, core measurement techniques, and the potential for advanced optical diagnostic techniques. Characterization results define the facility's performance metrics and limitations. A new test article mounting system has been constructed and tested to prevent flow blockage. Two measurement techniques, Focused Laser Differential Interferometry and High-Speed Schlieren, have been implemented into the tunnel to investigate its inflow noise and flow quality, respectively. Inflow uniformity and shear layer characteristics were obtained using a traversing Pitot tube system. Focused Laser Differential Interferometry was used to investigate the freestream turbulence of the Mach 6 nozzle by measuring the flow density fluctuations. All results suggest the Mach 6 nozzle of the wind tunnel produces flow with acceptable uniformity and turbulence levels for the types of measurements currently under study. Similar characterization of the Mach 2, 3, 4, 5, and 7 nozzles is ongoing.

  PublisherDOI

• Cavity Induced Trip Model for RANS in Hypersonic Flows

  2026-01-08

  articleSenior author

  A cavity-induced trip model was developed and implemented into US3D to simulate turbulent transition in hypersonic flows. The model leverages experimental wind tunnel data on cavity-induced transition at Mach 6.0 and Mach 10.0, along with local boundary layer data obtained from CFD simulations. The correlation was formulated based on a rectangular cavity volume, boundary layer height, displacement thickness Reynolds number, and edge-to-wall temperature ratio. The correlation yields a single parameter that can be used to determine whether a rectangular cavity will trip the flow. Preliminary results suggest that the correlation may be applicable to other geometries, particularly flat plates of varying pressure gradients at zero angle of attack. CFD simulations were performed to demonstrate the effectiveness of the correlation to differentiate between tripped and untripped flow based on incoming local flow variables and user-specified cavity dimensions. The model does not accurately predict the augmented heat flux caused by the cavity. Future work aims to incorporate a cavity trip strength into the trip model to predict the increase in heat flux and accurately capture the spreading angle of the turbulent region downstream of the trip.

  PublisherDOI

• Parametric Study of Forward-Facing Steps in Hypersonic Flow Using STARCCM+

  2026-01-08

  articleSenior author

  A parametric study investigating the effect of a forward-facing step discontinuity on a flat plate in hypersonic flow has been performed using the commercial STAR-CCM+ code to inform manufacturing defects for hypersonic vehicles. Mach number, step height, plate length (boundary layer development length), and free stream altitude were varied in a two-dimensional, ideal gas, steady simulation. A systematic dataset containing 500 unique cases were simulated, analyzed, and presented. Strategies for efficient computation of 2D hypersonic simulations using adaptive meshing are discussed. Results confirm that vertical steps which extend past 10% of the boundary layer height have a significant impact on pressure drag and local heating. Non-dimensional predictions for local impacts are presented. The influence of meshing, unsteadiness, the k-omega turbulence model, and shock wave-boundary layer interaction modeling on downstream effects is discussed.

  PublisherDOI

• Correction: Parametric Study of Forward-Facing Steps in Hypersonic Flow Using STARCCM+

  2026-01-12

  articleSenior author
  PublisherDOI

• Empirical Model for Low-Speed Rough-Wall Turbulent Boundary Layer Pressure Spectra

  AIAA Journal · 2022-03-10 · 2 citations

  article1st authorCorresponding

  An empirical model for estimating surface pressure spectra in high Reynolds number rough-wall turbulent boundary layers in the low-speed regime is presented. The model is based on the low-frequency mean velocity defect scaling [1] and the high-frequency shear friction velocity scaling [2]. This model satisfactorily predicts surface pressure spectra measured over a wide range of roughness configurations in high Reynolds number flows free of transitional effects. These data also provide insights into the characteristics of the turbulent scales which are on the order of the roughness size and comprise the mid-frequency region. The slope of this region is highly dependent on roughness element density and element-relative measurement location. This contradicts the premise of an overlap region with slope . An evanescent pressure decay model provides evidence that the slope changes are due to a roughness-dependent pressure decay within the interstitial flow and suggests that a traditional mid-frequency similarity law may not be possible.

  PublisherDOI

• Modeling of Axial Compressor With Large Tip Clearances

  Journal of Turbomachinery · 2021 · 9 citations

  • Computer Science
  • Computer Science
  • Mechanical engineering

  Abstract In the drive for lower fuel consumption through increased bypass ratio and increased overall pressure ratio (OPR), engine designs for the next generation of single-aisle aircraft will require core sizes below 3 lb/s and OPRs above 50. Traditionally, these core sizes are the domain of centrifugal compressors, but materials limit pressure ratio in these machines to well below 50. An all-axial high-pressure compressor (HPC) at this core size, however, comes with limitations associated with the small blade spans at the back of the HPC, as clearances, fillets, and leading edges do not scale with the core size. The result is a substantial efficiency penalty, driven primarily by the tip leakage flow produced by the larger clearance-to-span ratio, which negates the cycle efficiency benefits of the high OPR. In order to enable small-core, high-OPR, all-axial compressors mitigating technologies need to be developed and implemented to reduce the large clearance-to-span efficiency penalty. However, for this technology development to be successful, it is imperative that predictive design tools accurately model the overall flow physics and trends of the technologies developed. In this paper, we describe an effort to determine whether different modeling standards are required for a large clearance-to-span ratio, and if so, identify criteria for an appropriate solver and/or mesh. Multiple models are run and results compared with data collected in the NASA Glenn Research Center’s low-speed axial compressor. These comparisons show that steady Reynolds-averaged Navier–Stokes (RANS) solvers can predict the pressure-rise characteristic to an acceptable level of accuracy, if careful attention is paid to mesh topology in the tip region. However, unsteady tools are necessary to accurately capture radial profiles of blockage and total pressure. The Delayed-Detached Eddy Simulation model was also used to run this geometry, but did not resolve any additional features not captured by the unsteady RANS simulation near stall.

  PublisherDOI

• The low-frequency pressure fluctuations of near-equilibrium turbulent boundary layers

  Experiments in Fluids · 2021 · 4 citations

  1st authorCorresponding
  • Physics
  • Mechanics
  • Optics
  PublisherDOI

• Modeling of Axial Compressor With Large Tip Clearances

  2021-07-16

  preprint
  PublisherDOI

• Modeling of Axial Compressor With Large Tip Clearances

  2020-09-21 · 2 citations

  article

  Abstract In the drive for lower fuel consumption through increased bypass ratio and increased overall pressure ratio (OPR), engine designs for the next generation of single-aisle aircraft will require core sizes below 3 lb/s and OPRs above 50. Traditionally, these core sizes are the domain of centrifugal compressors, but materials limit pressure ratio in these machines to well below 50. An all-axial high pressure compressor (HPC) at this core size, however, comes with limitations associated with the small blade spans at the back of the HPC, as clearances, fillets and leading edges do not scale with the core size. The result is a substantial efficiency penalty, driven primarily by the tip leakage flow produced by the larger clearance-to-span ratio, which negates the cycle efficiency benefits of the high OPR. In order to enable small-core, high-OPR, all-axial compressors mitigating technologies need to be developed and implemented to reduce the large clearance-to-span efficiency penalty. However, for this technology development to be successful, it is imperative that predictive design tools accurately model the overall flow physics and trends of the technologies developed. In this paper we describe an effort to determine whether different modeling standards are required for a large clearance-to-span ratio, and if so, identify criteria for an appropriate solver and/or mesh. Multiple models are run and results compared with data collected in the NASA Glenn Research Center’s Low-Speed Axial Compressor. These comparisons show that steady Reynolds-Averaged Navier-Stokes (RANS) solvers can predict the pressure-rise characteristic to an acceptable level of accuracy, if careful attention is paid to mesh topology in the tip region. However, unsteady tools are necessary to accurately capture radial profiles of blockage and total pressure. The Delayed-Detached Eddy Simulation model was also used to run this geometry, but did not resolve any additional features not captured by the unsteady RANS simulation near stall.

  PublisherDOI

• Characteristics of the pressure fluctuations generated in turbulent boundary layers over rough surfaces

  Journal of Fluid Mechanics · 2019-11-20 · 14 citations

  article1st author
  PublisherDOI

Frequent coauthors

• Sean Nolan

  Whitney Museum of American Art

  13 shared

• William J. Devenport

  11 shared

• Sameer Kulkarni

  6 shared

• Junsok Yi

  General Electric (Israel)

  5 shared

• Michael Ni

  AeroDynamic Solutions (United States)

  5 shared

• Simon Evans

  Hartford Financial Services (United States)

  4 shared

• Aurélien Borgoltz

  Virginia Tech

  4 shared

• Nicholas J. Molinaro

  Ahmic Aerospace (United States)

  3 shared

Labs

• PHASE Research GroupPI

Awards & honors

• Virginia Space Grant Consortium (VSGC) New Investigator Prog…
• Outstanding Professional Achievement Award, Spectral Science…
• Student Speaker, Graduate Commencement Ceremonies, Virginia…
• Tolson Fellowship (2016)
• New Horizon Graduate Scholar, College of Engineering, Virgin…