William A. Sirignano

Distinguished Professor
Mechanical and Aerospace Engineering
University of California, Irvine

Personal information

Address 3202 Engineering Gateway
University of California Irvine
Irvine, CA 92697-3975
E-mail sirignan at uci.edu
Phone 949.824.3700
Fax 949.824.3772
Professional Interests Spray Combustion, Turbulent Combustion and Ignition, Aerospace Propulsion, Rocket Combustion Instability, Liquid Injection, Flow and Transport at Supercritical Pressures, Flamelet Theory, Automotive Combustion, Energy Conversion and Air Pollution, Fire Research, Noise Suppression, and Applied Mathematics

Professor at UC Irvine

Dr. Sirignano was a Professor at Princeton University from 1967 to 1979 after receiving his Ph.D. from there in 1964. He was the George Tallman Ladd Professor and Department Head at Carnegie-Mellon University from 1979 to 1984 before becoming the Engineering Dean at UCI. He left the deanship and currently he is a Distinguished Professor of Mechanical and Aerospace Engineering at UCI.

Click here for a more detailed biography.

Accomplishments and Recognition

Professor Sirignano's major forefront research accomplishments include:

  • Analysis predicting periodic nonlinear oscillations with shockwaves in an unstable combustor
  • Explanation of the nonlinear fluid dynamics associated with Helmholtz resonators
  • Determination of admittance for oscillatory, three-dimensional nozzle flows
  • Theory for condensed-phase behavior in flame spread above liquid and solid fuels
  • Theory for ignition of combustible gas by a hot projectile
  • Resolution of vorticity mechanisms in liquid stream breakup
  • Improved understanding of multi-branched flames
  • Development of new flamelet model for turbulent combustion with three-dimensional structure and vorticity
  • Resolution of turbulent flame and propagation in reciprocating and rotary internal combustion engines
  • Theory of droplet vaporization and convective heating with internal circulation; computational methods for spray flows
  • Theory of droplet interactions in a dense spray
  • Analysis of driving mechanisms for combustion instability in rockets and ramjets
  • Stochastic analysis of trigger for nonlinear combustion instability
  • Concept and analysis for improved efficiency and increased thrust with turbine burners
  • Concept and analysis for miniature combustors with liquid-fuel films
  • Analysis of fluid flow in trans-critical and supercritical thermodynamic states

Professor Sirignano has been widely recognized for the quality and impact of the research from his team. The recognition must be shared with many graduate student and postdoctoral researchers.

  • Honorary Fellow, 2023, American Institute of Aeronautics and Astronautics.
    AIAAHonorary Fellows are persons of eminence in aeronautics or astronautics, recognized by a long and highly contributive career in the arts, sciences, or technology thereof. Citation: For pioneering research in combustion dynamics, atomization and spray, and innovative concepts for propulsion and power, as well as outstanding educational leadership and professional service.
  • Special Issue of Combustion Science and Technology, Volume 192, Issue 7, 2020, pp. 1137-1447 Frontiers of Fluid and Thermal Sciences in Aerospace Engineering.
    In Celebration of 60 Years of Scholarly Contributions by Professor William A. Sirignano.
  • Frontiers of Fluid and Thermal Sciences in Aerospace Engineering.
    In Celebration of 60 Years of Scholarly Contributions by Professor William A. Sirignano held September 6-7, 2019 in Irvine CA. See photos at https://photos.google.com/share/AF1QipNjSpDZo43g_CKwB9J1OBRizQZq9PUZKWyLqtecsVsaoQcius7tzWuWbywn_gmvvQ?pli=1&key=TDM5cGEzeFgza2Y4R2VEQnJwSkFqVzBiaThXYUpR.
  • Combustion Institute Inaugural Fellow, 2018.
    Citation: “For groundbreaking research towards understanding the multitude of processes associated with the combustion of droplets and sprays.”
  • Wyld Propulsion Award, 2009, American Institute of Aeronautics and Astronautics.
    Citation: “For extensive and fundamental contributions to the advancement of chemical rocket propulsion through theories of nonsteady combustion and fluid dynamics.”
  • Society for Industrial and Applied Mathematics Inaugural Fellow, 2009.
    Citation: For contributions to fluid dynamics, combustion theory, and their applications to propulsion.
  • Energy Systems Award, 2004, American Institute of Aeronautics and Astronautics.
    Citation “For fundamental pioneering research on fuel atomization, spray combustion, and turbulent flows in gas-turbine and automotive engines, and for the innovative turbine-burner and miniature-liquid-fuel-film-combustor concepts”.
  • National Academy of Engineering, elected 2002.
    Citation: "For contributions to the science and technology of spray combustion systems for propulsion."
  • American Physical Society Fellow, 2000.
    Citation: "For his pioneering efforts in combining modeling and simulation of complex multiphase flows, and for the understanding these models have provided for pool fires and capillary instabilities."
  • The Combustion Institute, Alfred C. Egerton Medal, 1996
    Citation: "For distinguished, continuing, and encouraging contributions to the field of combustion."
  • American Electronics Association, Orange County Council, President's Award for Engineering Excellence In Service To Education, 1994.
    Citation: "In recognition and appreciation for outstanding contribution to the Orange County Technology Community."
  • IDERS Oppenheim Award, 1993.
    Citation: "In recognition of his outstanding contributions to the theory of non-linear rocket instability, spray dynamics and combustion in heterogeneous systems."
  • UC Irvine Alumni Distinguished Research Award, 1992.
  • Propellants and Combustion Award, 1992, American Institute of Aeronautics and Astronautics.
    Citation: "For his pioneering and outstanding contributions in the areas of combustion instability, spray vaporization and combustion, flame spreading, and modeling of internal combustion engines."
  • Freeman Scholar Award, 1992, American Society of Mechanical Engineers, Fluids Engineering Division, for Research on Fluid Dynamics of Sprays.
  • Edward G. Pendray Aerospace Literature Award, 1991, American Institute of Aeronautics and Astronautics.
    Citation: "For his numerous, exceptionally clear, and important contributions to the technical literature of combustion, non-steady fluid mechanics and heat transfer that are recognized as quality references in the fields of air and space flight, noise pollution, air pollution, fire safety, and energy conservation."
  • AAAS Fellow, 1992
  • ASME Fellow, 1989
  • AIAA Fellow, 1987
  • United Aircraft Research Fellow, 1973-74

Information for Students

PLEASE READ THE INFORMATION BELOW CAREFULLY IF YOU HAVE ANY INTEREST IN WORKING AS A STUDENT WITH PROFESSOR SIRIGNANO. Realize that he receives many informal inquiries from prospective students daily and IS NOT ABLE TO RESPOND because of the huge amount of time that would be required for responses to all of these communications. Please appreciate that his teaching, student mentoring, and research obligations demand his full attention; thus, an efficient means of communication with prospective students is needed. This website is designed to give those students as much useful information as possible about Professor Sirignano and his research and education interests.

There should be positions for new graduate students this coming Fall in our research group. Stipends and support for tuition and fees can be available when required for admitted students. Professor Sirignano cannot respond with any advice to an inquiry by a prospective graduate student who informally sends a CV and asks for an evaluation of the likelihood of gaining entrance. It is not possible to make a meaningful assessment of any individual's qualifications or likelihood of success at admission without seeing the completed formal application with reference letters in the standard format, transcripts, and official reports of GRE scores. So, it is best to make the formal application if you have a strong interest. If you note on your application that you have a special interest in performing your research for the MS Thesis and / or PhD dissertation with Professor Sirignano, that application should be circulated to him by our administrators responsible for application processing and then he will carefully examine it.

As noted elsewhere in this web site, graduate students who have worked with Professor Sirignano have generally enjoyed very successful professional careers in academia, government, and industry. Several topics of major interests are studied within the group at any one time. The list of publications and the copies of slide presentations for research seminars, given elsewhere in this web site, should provide a useful overview of the research activities. The available graduate courses and degree requirements can be found at the UCI MAE web site http://mae.eng.uci.edu

Many students, especially from foreign universities, communicate with us requesting a research internship with Professor Sirignano. We only accommodate students who are prepared to pay their own costs and can stay for a period of at least one year, which is a minimal time to accomplish a significant piece of research. We receive a large number of internship requests; so, if the ability to spend a year is not clearly stated in the communication from the student, we do not respond. Evidence of top academic standing and four years of university education is required.

Status of Former PhD Students and Postdocs

J.S. Tien1970Professor, Case Western Reserve
T.S. Tonon1972Solar engineering industry, New Jersey
P. Tang1972Researcher, Los Alamos National Laboratory, JPL
A.K. Varma1972Researcher, Bell Laboratories
C. Bruno1973Professor, University of Rome, Consultant, UTRC
J.R. Bellan1974Senior Scientist, JPL; Lecturer, Cal Tech
T.J. Rosfjord1974Manager, United Technologies Research Center
S. Prakash1978Professor, University of Roorkee, Hewlett-Packard
J.I. Ramos1980Professor, Carnegie Mellon University and University of Malaga
Y.P. Su1981Propulsion Chief, Lung-Tan Taiwan Government Laboratory
M. Micci1981Professor, Pennsylvania State University
A. Birk1981Researcher, Army Ballistics Research Laboratory
S.T. Lerner1981Senior VP and Chief Technical Officer, Praxair
S. Parker1981Researcher, Aeronautical Research Associates at Princeton
A.Y. Tong1983Professor, University of Texas, Arlington
P. Givi1984Distinguished Professor, University of Pittsburgh
G. Patnaik1985Researcher, Naval Research Laboratories
A. Eaton1988Researcher, Brigham Young University
K. Molavi1990Engineering Consultant, Irvine
C.H. Chiang1990Professor, KaoShiung Polytech Institute, Taiwan
D. Schiller1991Engineer, Boeing, Huntington Beach
R. Bhatia1993Manager, Dell Inc., Intel
J.P. Delplanque1993Professor and Dean of Graduate Studies, University of California, Davis
M. Masoudi1998Engineer, Bosch
C. Mehring1999Professor, University of Stuttgart
F. Cheng2008Family manufacturing business, Hong Kong
S. Dabiri2009Assistant Professor, Purdue University
G. Wu2010Researcher, FLUENT, General Electric
B. Colcord2011Data analyst, New Zealand Air
D. Jarrahbashi2014Assistant Professor, Texas A&M
T. M. Nguyen2018Researcher, Lawrence Livermore Laboratories
A. Jorda Juanos2018Researcher, Simerics, Inc.
A. Zandian2018Researcher, Convergent Science Inc., Tesla
J. Poblador-Ibanez2022Researcher, Argonne Labs
A. ChervinskyDeceased, formerly Lecturer, Technion
O.P. SharmaProfessor, IIT, Kampur
C.C. FengProfessor, Trenton State College
C.K. LawProfessor, Princeton University
F.V. BraccoDeceased, formerly Professor, Princeton University
H.S. HomanExxon Research Laboratories
J. HumphreyDeceased, formerly Professor, UCB and U. of Va.
A. GanyProfessor, Technion
L. CavenyAir Force SDI Office
S.K. AggarwalProfessor, University of Illinois, Chicago
R. TalIsrael Defense Industry
R.H. RangelProfessor, UCI
M.S. RajuNYMA Researcher at NASA Glenn
B. AbramzonConsultant, Israel
B. CetegenProfessor and Department Chair, University of Connecticut
G. ContinilloResearcher, CNR, Italy and Professor, Universita del Sannio
C.M. MegaridisProfessor, University of Illinois, Chicago
F.H. TsauResearcher, Industrial Technical Institute, Taiwan
E. GutheilProfessor, University of Heidelberg
J. CaiProfessor, Northwest Polytechnic University, China
P. PopovAssistant Professor, San Diego State University
J. XiongResearcher, NASA Ames
L. ZhanResearcher, GE Aviation

Publications, Projects & Courses

Two-Dimensional Model for Liquid-Rocket Transverse Wave Instability

Stochastic Modeling of Transverse Wave Instability in a Liquid Propellant Rocket Engine

Propellant Injector Influence on Liquid Propellant Rocket Engine Instability

Vorticity Dynamics for Transient High-Pressure Liquid Injection

Early Spray Development at High Gas Density: Hole, Ligament, and Bridge Formations

Transient Combustion of a Methane-Hydrate Sphere

Interaction Between a Cavitation Bubble and Shear Flow

A Numerical Study on the Effects of Cavitation on Orifice Flow

Simulation of Transient Convective Burning of an n-octane Droplet Using a Four-step Reduced Mechanism

Optimization of Secondary-Air Addition in a Continuous One-Dimensional Spray Combustor

Driving Mechanisms for Combustion Instability

Advances in Droplet Array Combustion Theory and Modelling

Turbine Burners: Performance Improvement and Challenge of Flameholding

Flameholding in Converging and Turning Channels over Cavities with Slot Injection

Flameholding in Converging and Turning Channels over Cavities with Periodic Port Injection

Triple flame: Inherent Asymmetries and Pentasectional Character

Transverse Combustion Instability in a Recatangular Rocket Motor

Triggering and Restabilization of Combustion Instability with Rocket Motor Acceleration

Two-Time-Variable Perturbation Theory for Liquid-Rocket Combustion Instability

Coaxial Jet Flame Subject to Long-Wavelength nAcoustic Oscillations

Combustion with Multiple Flames under High Strain Rates

Compressible Flow at High Pressure with Linear Equation of State

Engine-type and Propulsion-configuration Selections for Long-duration UAV Flights

Extinction Analysis of a Methane-Oxygen Counterflow Flame at High Pressure

Length-scale Cascade and Spray Expansion for Planar Liquid Jets

Longitudinal Combustion Instability in a Rocket Motor with a Single Coaxial Injector

Low-Probability Events Leading to Rocket Engine Combustion Instability

Nonlinear Combustion Instability in a Multi-Injector Rocket Engine

Normal Shocks with High Upstream Pressure

Numerical Simulation of Liquid Round Jet Atomization

Counterflow and wall stagnation flow with three-dimensional strain

Planar Liquid Jet Early Deformation and Atomization Cascades

Pressure Effects on Real-gas Laminar Counterflow

Spontaneous and Triggered Longitudinal Combustion Instability in a Rocket Engine

The Impacts of Three Flamelet Burning Regimes in Nonlinear Combustion Dynamics

Transient Behavior near Liquid-Gas Interface at Supercritical Pressure

Understanding Liquid-Jet Atomization Cascades Via Vortex Dynamics

Vorticity Dynamics in a Spatially Developing Liquid Jet Inside a Coflowing Gas

Nonlinear Combustion Instability with Multi-injectors

Combustion Dynamics Simulation of a 30-Injector Rocket Engine

Combustion Simulation of 82-Injector Rocket Engine

Neural Network Flame Closure for a Turbulent Combustor with Unsteady Pressure

Physics-aware neural network flame closure

Two-phase developing laminar mixing layer at supercritical pressures

Self-similar solution of a supercritical two-phase laminar mixing layer

Temporal atomization of a transcritical liquid n-decane jet into oxygen

Liquid-jet instability at high pressures with real-fluid interface thermodynamics

A volume-of-fluid method for variable-density, two-phase flows at supercritical pressure

Counterflow and wall stagnation flow with three-dimensional strain

Diffusion-controlled premixed flames


Reacting and non-reacting, three-dimensional shear layers with spanwise stretching

Combustion with Multiple Flames under High Strain Rates

Strain Rate and Pressure Effects on Multi-branched Flame


Inward swirling flamelet model - Inward swirling flamelet model

Stretched vortex layer flamelet

Photos of Interest | A Brief Account

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