Pedro Paredes Gonzalez

Education

• Ph.D, Technical University of Madrid, Spain, 2014
• M.Sc. (Research), Technical University of Madrid, Spain, 2011
• M.Sc., Technical University of Madrid, Spain, 2009

Work Experience

• Research Engineer II, National Institute of Aerospace, 2018-present
• NASA Postdoctoral Program Fellowship, NASA Langley Research Center, 2015-2018
• Postdoctoral Fellowship, Technical University of Madrid, 2014-2015

Research Areas/Expertise

• Hydrodynamics stability analysis techniques for complex flows
• Subsonic, supersonic, and hypersonic boundary layer transition prediction
• Laminar-Turbulent transition control
• Computational Fluid Dynamics

Current Research

Laminar Flow Control via Transient Growth Streaks 

A concept for extending the laminar flow area over supersonic and hypersonic flight configurations by delaying the transition of boundary layer flow from laminar to turbulent state is investigated. Laminar boundary layers are associated with nearly an order of magnitude lower skin friction than turbulent flows. Therefore, laminar flow technology is recognized as a potential breakthrough that would enable substantial reduction in aerodynamic drag, and hence, in fuel efficiency and environmental impact of supersonic vehicles; and reduced weight of thermal protection system and increased payload for hypersonic vehicles.

Multi-Fidelity Tools for Modeling of Boundary Layer Transition

According to CFD Vision 2030, the most critical area in CFD simulation capability that will remain a pacing item is the ability to adequately predict viscous turbulent flows with possible transition and flow separation. Current state of the art in transition prediction involves a combination of primarily empirical models with limited validity and physics based linear stability correlations that are not integrated into NASA CFD codes. This research will investigate multi-fidelity prediction tools for accurate prediction and control of boundary-layer transition via combined advances in physics-based transition prediction, coupling with RANS solvers, and integration of transition prediction with scale resolving simulation techniques such as LES/WMLES and hybrid RANS/LES.

Publications

Peer-reviewed journal articles

Gómez, F., Le Clainche, S., Paredes, P., Hermanns, M., Theofilis, V. (2012) “Four decades of studying global linear instability: progress and challenges”, AIAA J., 50, 2731-2743.

Paredes, P., Hermanns, M., Le Clainche, S., Theofilis, V. (2013) “Order 10⁴speedup in global linear instability analysis using matrix formation”, Comput. Meth. Appl. Mech. and Eng., 253, 287-304

Paredes, P., Rodríguez, D., Theofilis, V. (2013) “Three-dimensional solutions of trailing-vortex flows using parabolized equations”, AIAA J. 51, 2763-2770.

De Tullio, N., Paredes, P., Sandham, N.D., Theofilis, V. (2013) “Laminar-turbulent transition induced by a discrete roughness element in a supersonic boundary layer”, J. Fluid Mech., 735, 613-646.

Paredes, P., Theofilis, V. (2015) “The centerline global mode in Mach 7 flow on the HIFiRE-5 elliptic cone”, J. Fluid Struct., 53, 36-49.

Paredes, P., Terhaar, S., Oberleithner, K., Theofilis, V., Paschereit, C.O., (2016) “Global and local hydrodynamic stability analysis as a tool for combustor dynamics modeling” J. Eng. Gas Turb. Power, 138, 021504-1-7.

He, Wei, Tendero, J.A., Paredes, P., Theofilis, V., (2016) “Linear instability in the wake of an elliptic wing” Theor. Comp. Fluid Dyn., 31, (5-6), 483-504.

Martin, J.A., Paredes, P. (2016) “Three-dimensional instability analysis of boundary layers perturbed by streamwise vortices”, Theor. Comp. Fluid Dyn., 31, (5-6), 505-517.

Paredes, P., Gosse, R., Theofilis, V., Kimmel, R. (2016) “Linear modal instabilities of hypersonic flow over an elliptic cone”, J. Fluid Mech., 804, 442-466.

Paredes, P., Choudhari, M., Li, F., Chang, C.-L. (2016) “Optimal growth in hypersonic boundary layers”. AIAA Journal, 54 (10), 3050-3061.

Li, F., Choudhari, M., Paredes, P., Duan, L. (2016) “High-frequency instabilities of stationary crossflow vortices in a hypersonic boundary layer”. Phys. Rev. Fluids, 1, 053603.

Paredes, P., Choudhari, M., Li, F. (2016) “Transition due to streamwise streaks in a supersonic flat plate boundary layer”. Phys. Rev. Fluids, 1, 083601.

Lakebrink, M.T., Paredes, P., Borg, M.P., (2017) “Toward robust prediction of crossflow-wave instability in hypersonic boundary layers”. Comput. Fluids, 144, 1-9.

Moyes, A.J., Paredes, P., Kocian, T.S., Reed, H.L., (2017) “Secondary instability analysis of crossflow on a hypersonic yawed straight circular cone”. J. Fluid Mech., 812, 370-397.

Paredes, P., Choudhari, M., Li, F. (2017) “On blunt-body paradox and transient growth on a hypersonic spherical forebody”. Phys. Rev. Fluids, 2, 053903.

Paredes, P., Choudhari, M., Li, F. (2017) “Instability wave-streak interactions in a supersonic boundary layer”. J. Fluid Mech., 831, 524-553.

Paredes, P., Choudhari, M., Li, F. (2018) “Blunt body paradox and improved application of transient growth framework”. AIAA J., 56, 2604-2614.

Paredes, P., Choudhari, M., Li, F. (2018) “Instability wave-streak interactions in a hypersonic boundary layer at flight conditions”. J. Fluid Mech. (accepted).

Paredes, P., Choudhari, M., Li, F., Jewell, J.S., Kimmel, R.L., Marineau, E.C., Grossir, G. (2018) “Nosetip bluntness effects on transition at hypersonic speeds: Experimental and numerical analysis”. J. Spacecr. Rockets. (accepted).

Hein, S.J., Theiss, A., Di Giovanni, A., Stemmer, C., Schilden, T., Schroeder, W., Paredes, P., Choudhari, M.M., Li, F., Reshotko, E. (2018) “Numerical investigation of roughness effects on transition on spherical capsules”. J. Spacecr. Rockets. (accepted).

Paredes, P., Choudhari, M., Li, F., Jewell, J., Kimmel, R. (2019) “Nonmodal growth of traveling waves on blunt cones at hypersonic speeds”. AIAA J. (in review).

Muller, J., Luckoff, F., Paredes, P., Theofilis, V., Oberleithner, K. (2019) “Receptivity of the turbulent precessing vortex core: synchronization experiments and global adjoint linear stability analysis” J. Fluid Mech., (in review).

Technical Reports

Li, F., Choudhari, M., Paredes, P., Duan, L. (2015) “Secondary instability of stationary crossflow vortices in Mach 6 boundary layer over a circular cone”. NASA/TM-2015-218997.

Paredes, P., Choudhari, M., Li, F. (2016) “Transition delay in hypersonic boundary layers via optimal perturbations”. NASA/TM-2016-219210.

Book Chapters

Paredes, P., De Tullio, N., Sandham, N.D. and Theofilis, V. (2014) “Instability study of the wake behind a discrete roughness element in a hypersonic boundary-layer”, Instability and Control of Massively Separated Flows, Springer International Publishing, Switzerland

Tendero, J.A., Paredes, P., Roura, M., Govindarajan, R. and Theofilis, V. (2014) “Filament vortex and global instability analysis of the Crow mode”, Instability and Control of Massively Separated Flows, Springer International Publishing, Switzerland

Perez, J.A., Franco, J.A., Paredes, P., Hein, S., Hannemann, V., Theofilis, V. (2015) “Stability analysis of hypersonic flow over back-step in chemical equilibrium”, Proceedings of the 2015 summer program within the SFBTRR40 at Munich from July 20 – Aug 14, 2015

Conference Proceedings

De Vicente, J., Paredes, P., Valero, E., Theofilis, V. (2011) “Wave-like disturbances on the downstream wall of an open cavity”, 6th AIAA Theoretical Fluid Mechanics Conference, Honolulu, Hawaii, USA, 27 – 30 June 2011, AIAA 2011-3754

Paredes, P., Theofilis, V., Rodríguez, D., Tendero, J.A. (2011) “The PSE-3D instability analysis methodology for flows depending strongly on two and weakly on the third spatial dimension”, 6th AIAA Theoretical Fluid Mechanics Conference, Honolulu, Hawaii, USA, 27 – 30 June 2011, AIAA 2011-3752

Paredes, P., Theofilis, V., Rodríguez, D. (2012) “Parabolic Navier-Stokes solutions of trailing vortex”, 42nd AIAA Fluid Dynamics Conference, New Orleans, Louisiana, USA, 25 – 28 June 2012, AIAA 2012-3348

Gómez, F., Theofilis, V., Paredes, P., Liu, Q., He, W. (2012) “On the role of global flow instability analysis in closed loop flow control”, 6th AIAA Flow Control Conference, New Orleans, Louisiana, USA, 25 – 28 June 2012, AIAA 2011-3754

Gómez, F., Paredes, P., Gómez, R., Theofilis, V. (2012) “Global stability of cubic and large aspect ratio three-dimensional lid-driven cavities”, 42nd AIAA Fluid Dynamics Conference, New Orleans, Louisiana, USA, 25 – 28 June 2012, AIAA 2012-3274

Paredes, P., Theofilis, V. (2013) “Accurate Parabolic Navier-Stokes solutions of the supersonic flow around and elliptic cone”, 51st AIAA Aerospace Sciences Meeting, Grapevine, Texas, USA, 7 – 10 January 2013, AIAA 2013-0670

Tendero, J.A., Paredes, P., Roura, M., Govindarajan, R.,Theofilis, V. (2013) “BiGlobal and point vortex methods for the instability analysis of wakes”, 43rd AIAA Fluid Dynamics Conference, San Diego, California, USA, 24 – 27 June 2013, AIAA 2013-2820

Paredes, P., Gennaro, E., Hermanns, M., Theofilis, V. (2013) “On global linear instability analysis of hypersonic flow around a model re-entry vehicle”, 43rd AIAA Fluid Dynamics Conference, San Diego, California, USA, 24 – 27 June 2013, AIAA 2013-2820

Paredes, P., Theofilis, V. (2013) “Spatial linear global instability analysis of the HIFiRE-5 elliptic cone model flow”, 43rd AIAA Fluid Dynamics Conference, San Diego, California, USA, 24 – 27 June 2013, AIAA 2013-2880

Paredes, P., Theofilis, V. (2014) “Traveling global instabilities on the HIFiRE-5 elliptic cone model flow”, 52nd AIAA Aerospace Science Meeting, National Harbor, Maryland, USA, 13 – 17 January 2014, AIAA 2014-0075

Paredes, P., Gennaro, E., Theofilis, V. (2014) “Toward reliable and efficient laminar-turbulent flow transition predictions in supersonic and hypersonic flows over complex geometries”, 54th Israel Annual Conference on Aerospace Sciences, Tel-Aviv & Haifa, Israel, 19 – 20 February 2014.

Paredes, P., Perez, E., Reed, H.L., Theofilis, V. (2014) “High-frequency instabilities along the windward face of a hypersonic yawed circular cone”, 7th Theoretical Fluid Mechanics Conference, Atlanta, GA, USA, 16 – 20 June 2014, AIAA 2014-2774

Terhaar, S., Paredes, P., Oberleithner, K., Theofilis, V., Paschereit, C.O. (2014) “Investigation of the global mode in swirling combustor flows: experimental observations and local and global stability analysis”, 8th IUTAM Laminar-Turbulent Transition, Rio de Janeiro, Brazil, 8 – 12 September 2014. Procedia IUTAM, 14, 553 – 562

Martin, J.A., Martel, C., Paredes, P., Theofilis, V. (2014) “Numerical studies of non-linear intrinsic streaks in the flat plate boundary layer”, 8th IUTAM Laminar-Turbulent Transition, Rio de Janeiro, Brazil, 8 – 12 September 2014. Procedia IUTAM, 14, 479 – 486

Perez, J.M., Paredes, P., Theofilis, V. (2014) “Stability analysis of shock-wave dominated flow over a transonic bump”, 8th IUTAM Laminar-Turbulent Transition, Rio de Janeiro, Brazil, 8 – 12 September 2014. Procedia IUTAM, 14, 503 – 510

Paredes, P., Hanifi, A., Theofilis, V., Henningson, D.S. (2014) “The nonlinear PSE-3D concept for transition prediction in flows with a single slowly-varying spatial direction”, 8th IUTAM Laminar-Turbulent Transition, Rio de Janeiro, Brazil, 8 – 12 September 2014. Procedia IUTAM, 14, 36 – 44

Terhaar, S., Paredes, P., Oberleithner, K., Theofilis, V., Paschereit, C.O. (2015) “Global and local hydrodynamic stability analysis as a tool for combustor dynamics modeling”, ASME Turbo Expo 2015, Montreal, Canada, 15 – 19 June 2015. GT2015-44173

Paredes, P., Choudhari, M.M., Li, F., Chang, C.-L. (2016) “Transient growth analysis of compressible boundary layers with Parabolized Stability Equations”, 54th AIAA Aerospace Sciences Meeting, San Diego, CA, USA, 4 – 8 June 2016, AIAA 2016-0051

Kuehl, J., Paredes, P. (2016) “Gortler modified Mack-modes on a hypersonic flared cone”, 54th AIAA Aerospace Sciences Meeting, San Diego, CA, USA, 4 – 8 June 2016, AIAA 2016-0849

Moyes, A., Paredes, P., Kocian, T.S., Reed, H.L. (2016) “Secondary instability analysis of crossflow on a hypersonic yawed straight circular cone”, 54th AIAA Aerospace Sciences Meeting, San Diego, CA, USA, 4 – 8 June 2016, AIAA 2016-0848

Paredes, P., Choudhari, M., Li, F. (2016) “Nonlinear transient growth and boundary layer transition”. 46th AIAA Fluid Dynamics Conference, AIAA Aviation 2016, Washington DC, USA, 13 – 17 June 2016. AIAA 2016-3956

Choudhari, M., Li, F., Paredes, P. (2016) “Influence of stationary crossflow modulation on secondary instability”. 46th AIAA Fluid Dynamics Conference, AIAA Aviation 2016, Washington DC, USA, 13 – 17 June 2016. AIAA 2016-3788

Paredes, P., Choudhari, M., Li, F. (2017) “Transient growth and streak instabilities on a hypersonic blunt body”. 55th AIAA Aerospace Sciences Meeting, Grapevine, TX, USA, 9 – 13 January 2017. AIAA 2017-0066

Choudhari, M., Li, F., Paredes, P., Duan, L. (2017) “Computations of crossflow instability in hypersonic boundary layers”. 47th AIAA Fluid Dynamics Conference, AIAA Aviation 2017, Denver, CO, USA, 5 – 9 June 2017. AIAA 2017-4300

Paredes, P., Choudhari, M., Li, F. (2017) “Stabilization of hypersonic boundary layers by linear and nonlinear optimal perturbatios”. 47th AIAA Fluid Dynamics Conference, AIAA Aviation 2017, Denver, CO, USA, 5 – 9 June 2017. AIAA 2017-3634

Paredes, P., Choudhari, M., Li, F., Jewell, J.S., Kimmel, R.L., Marineau, E.C., Grossir, G. (2018) “Nosetip bluntness effects on transition at hypersonic speeds: experimental and numerical analysis under NATO STO AVT-240”. 56th AIAA Aerospace Sciences Meeting, Kissimmee, FL, USA, 8 – 12 January 2018. AIAA 2018-0057

Hein, S.J., Theiss, A., Di Giovanni, A., Stemmer, C., Schilden, T., Schroeder, W., Paredes, P., Choudhari, M.M., Li, F., Reshotko, E. (2018) “Numerical investigation of roughness effects on transition on spherical capsules”, 56th AIAA Aerospace Sciences Meeting, Kissimmee, FL, USA, 8 – 12 January 2018. AIAA 2018-0058

Choudhari, M.M., Li, F., Paredes, P., Duan, L. (2018) “Nonlinear evolution and breakdown of azimuthally compact crossflow vortex pattern over a yawed cone”, 56th AIAA Aerospace Sciences Meeting, Kissimmee, FL, USA, 8 – 12 January 2018. AIAA 2018-1823

Paredes, P., Choudhari, M.M., Li, F. (2018) “Transition delay via vortex generators in a hypersonic boundary layer at flight conditions”, AIAA AVIATION Forum, 2018 Fluid Dynamics Conference, Atlanta, GA, USA, 25 – 29 June 2018. AIAA 2018-3217.

Choudhari, M.M., Li, F., Paredes, P. (2018) “Effect of distributed patch of smooth roughness elements on transition in a high-speed boundary layer”, AIAA AVIATION Forum, 2018 Fluid Dynamics Conference, Atlanta, GA, USA, 25 – 29 June 2018. AIAA 2018-3532.

Li, F., Choudhari, M.M., Paredes, P., Schneider, S.P., Portoni, P. (2018) “Goertler instability and its control via surface suction over an axisymmetric cone at Mach 6”, AIAA AVIATION Forum, 2018 Fluid Dynamics Conference, Atlanta, GA, USA, 25 – 29 June 2018. AIAA 2018-3069.

Paredes, P., Chouhdari, M., Li, F., Jewell, J., Kimmel, R. (2019) “Nonmodal growth of traveling waves on blunt cones at hypersonic speeds”, AIAA SCITECH 2019 Forum, San Diego, CA, USA, 7 – 11 January 2019. AIAA 2019-0876.

Chouhdari, M., Li, F., Paredes, P., Duan, L. (2019) “Effect of 3D roughness patch on instability amplification in a supersonic boundary layer”, AIAA SCITECH 2019 Forum, San Diego, CA, USA, 7 – 11 January 2019. AIAA 2019-0877.