Description and formulation of wave problems in the ocean, development of classical wave theory, free waves and forced waves induced by pulsating and uniformly translating pressures and sources in steady and unsteady states, diffraction, refraction and reflection of waves, application to floating breakwaters, and harbor oscillations.
Development of the kinematic and dynamic equations for incompressible fluid flow, the Navier-Stokes equation, velocity potential and stream function, Bernoulli's equation, conformal mapping, free surface flows, wave theory, flow in porous media, and turbulence.
Potential flows around bodies: panel singularities methods and conformal mapping methods. Finite-difference and spectral methods for Poisson equations: numerical inversion of matrices, and potential flows in or around irregular domains. Consistency, stability, and convergence of numerical methods: linear stability analysis. Numerical methods for diffusion equations and methods for ordinary differential equations. One-dimensional Burger's equation and nonlinear problems, Newton iteration, error analysis. Numerical methods for stream function vorticity equations: flows in or around irregular domains. Discussions of current research in computational fluid dynamics. Four exercise projects and one examination project will be assigned to each student. Prerequisite: Computer Programming.
Computer-aided design procedures to achieve mission requirements for various ship types through design spirals. Determination of major dimension and performance analysis during preliminary design stage. Computer graphics on mainframe and microcomputers as design tools. Pertinent design procedures are covered in a computer-aided manner.
Calculation of hydrostatic curves to determine trim and sinkage of sailing yachts, static and dynamic stability, calculation of resistance and side force by expansion of tank test results, sail force coefficients, prediction of comparative performance based on tank test results, application of lifting surface theory to the design of keel and rudder, and consideration of structural strength and stiffness.
Schaefer School of Engineering & Science
Civil, Environmental and Ocean Engineering
Center for Maritime Systems
Research & Education
Dr. Imas' primary research interests are in the development and utilization of computational fluid mechanics and optimization methods in design analysis applications involving marine hydrodynamics and low speed aerodynamics.
PhD, 1998, MIT, Hydrodynamics, Department of Ocean Engineering
MEng, 1992, Rensselaer Polytechnic, Aeronautical Engineering, Department of Mechanical and Aeronautical Engineering and Mechanics
BS, 1990, Rensselaer Polytechnic, Aeronautical Engineering, Department of Mechanical, Aeronautical Engineering and Mechanics
Experience & Service
Areas of Interest and Expertise
design of experiments and numerical optimization
numerical simulation of external flow around complex geometries
o free-surface and multi-phase flows o cavitation o turbulent and transitional flow modeling o fluid-structure interaction
simulation-based engineering and numerical optimization analysis for high performance yacht r&d and design
Research Associate Professor, Davidson Laboratory, Stevens Institute of Technology
Principal Scientist, Fluid Mechanical Systems Group, Anteon Corporation
Lead Research Scientist, DeepWater Development Group, Chevron-Texaco Energy Company
Director, undergradate Naval Engineering program
Udergraduate Curriculum Committe
Chair, Library Committe
National Academy of Sciences panel on Naval Engineering in the 21st Century - Panel Member (2010 - 2011)
ASEE Ocean and Marine Engineering Division - Program Chair (2011 - 2012)
Achievements & Professional Societies
American Institute of Aeronautics and Astronautics (AIAA)
Society of Naval Architects and Marine Engineers (SNAME)
Tau Beta Pi (National Engineering Honor Society)
Sigma Gamma Tau (National Aeronautical Engineering Honor Society)
R. Garo, L. Imas, R. Datla. (Jun 2012). "Numerical Simulation of Planing Hull Hydrodynamics", 3rd Chesapeake Powerboat Symposium.
R. Garo, L. Imas. (Mar 2012). "Hydrodynamic Performance of a Submerged Lifting Surface Operating Near The Air-Water Interface At High Speeds,", 4th High-Performance Yacht Design (HPYD) Conference.
R, Paredes, L. Imas. (Sep 2011). "Application of SPH in Fluid-Structure Interaction Problems Involving Free-surface Hydrodynamics", to appear in the proceedings of 11th International Conference on Fast Sea Transportation, FAST 2011, Honolulu, Hawaii, USA.
T. Yen, M. Morabito, L. Imas, J. Dzielski, R. Datla. (Sep 2011). "Investigation of Cylinder Planing on a Flat Free Surface", to appear in the proceedings of 11th International Conference on Fast Sea Transportation, FAST 2011, Honolulu, Hawaii, USA.
W. Rees, L. Imas. (Dec 2008). "A Numerical Investigation Into the Hydrodynamic Performance of a Fin With a Scalloped Leading Edge", In refereed conference proceedings of the 3rd High-Performance Yacht Design (HPYD) Conference, Auckland, New Zealand.
L. Imas, G. Buley, B. Baker, B. Ward. (Dec 2008). "High Fidelity CFD Simulations in Racing Yacht Aerodynamic Analysis", In refereed conference proceedings of the 3rd High-Performance Yacht Design (HPYD) Conference, Auckland, New Zealand.
L. Imas, J.B. Braun. (Dec 2008). "CFD-Based Hydrodynamic Analysis of High Performance Racing Yachts", In refereed conference proceedings of the 3rd High-Performance Yacht Design (HPYD) Conference, Auckland, New Zealand.
PENROSE, J., JONES, I., ZWART, P., IMAS, L.. (Mar 2008). "Application of CFD to Flows around Marine Vessels. Sink and Trim", In the Proceedings of the Royal Institution of Naval Architects Marine CFD Conference.
IMAS, L. (Jun 2007). "CFD Modelling of Surfboard Hydrodynamics (keynote presentation)", In the Proceedings of the 1st International Aerospace CFD Conference, Paris, France.
IMAS, L., GRANT J., KRING, D., MILEWSKI, W.. (Sep 2003). "Investigation of Free-SInvestigation of Free-Surface Flow In the Near-Field Of An Advancing Surface-Piercing Body Using Three-Dimensional Smoothed Particle Hydrodynamics", In the Proceedings of the 8th International Conference on Numerical Ship Hydrodynamics, Busan, Korea.
KIRSCHNER, I., IMAS, L.. (2002). "Plume-Supercavity Interaction. Proceedings of the International Summer Scientific School on High-Speed Hydrodynamics", Cheboksary, Russia. 147-157.
AUDIBERT, J., HSU, T., IMAS, L., LITTON, D., THOMPSON, H., TRIANTAFYLLOU, M., & YOUNG, R.. (Nov 2000). "Coupled hydrodynamic and structural design analysis of the Typhoon large-diameter SCR", In DOT 2000 Conference Proceedings, New Orleans, LA.
KAVANAGH, W. K., IMAS, L., THOMPSON, H., & LEE, L.. (May 2000). "Genesis spar risers: interference assessment and VIV model testing", Paper 11992, OTC 2000 Conference Proceedings, Houston, TX.
KORPUS, R., IMAS, L., & OAKLEY, O. O.. (May 2000). "Prediction of viscous forces on free and forced oscillating cylinders by Navier-Stokes Techniques", In ISOPE 2000 Conference Proceedings, Seattle, WA.
Air turbulence-induced vibration of SCUBA breathing apparatus. (2007). "Dimitri Donskoy, Len Imas, Timothy Yen, Nikolay Sedunov, Michael Tsionskiy", J Acoust Soc Am, 122 (5), 2965 .
Dov Kruger, Hongyuan Shi, Mina Samaan, Jeffrey V. Nickerson, Len Imas. (2009). "Dynamic UUV Path Planning in an Estuarine Current Field", US Navy Journal of Underwater Acoustics; JUA(USN) . 59 449-464 .
Dov Kruger, Hongyuan Shi, Mina Samaan, Donald Chesley, Jeffrey V. Nickerson, Len Imas. (2009). "High Speed Localization Using a Multiple Analytical Distribution Filter", US Navy Journal of Underwater Acoustic, JUA(USN) , 59 465-481 .
LUCOR, D., EVANGELINOS, C., IMAS, L., & KARNIADAKIS, E. M. (Oct 2002). "Flow induced vibrations of non-linear cables, Part II: Simulations", International Journal for Numerical Methods in Engineering, 55 (5), 557 – 571.
LUCOR, D., IMAS, L., & KARNIADAKIS, E. M. (2001). "Vortex dislocations and force distributions of long flexible cylinders subjected to sheared flows", Journal of Fluids and Structures, 15 641-650.
Naval Engineering in the 21st Century. (2011). "The Science and Technology Foundation for Future Naval Fleets", Special Report 306, published by Transportation Research Board of the National Academies of Science.