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Ravi Challa, Ph.D.

**** ***** **** ***, *** #150, Sacramento, CA 95831 Ph. # +1-916-***-**** Email: adcvn0@r.postjobfree.com SUMMARY OF QUALIFICATIONS

Experienced project engineer with a demonstrated history of working in the civil, ocean/marine and energy industry with focus on experimental and computational modeling and simulation of civil and ocean engineering problems involving fluids (ocean) and structures. Projects involved in are:

• Development and validation of an accurate real-time numerical wave prediction modeling system that can be used in an optimal control framework for different Wave Energy Converter (WEC) devices and concepts.

• Numerical modeling and simulations: Finite Element Analysis (FEA), Computational Fluid Dynamics (CFD), Smoothed Particle Hydrodynamics (SPH), hydrodynamic contact/impact, multi-body mechanics/dynamics, fully coupled fluid structure interaction systems (FSI) analysis, use and development of simulation models and analyzing data using state-of-the-art computational codes and calibration with physical experiments. EDUCATION

Doctor of Philosophy – Civil/Ocean Engineering December 2014 Oregon State University, Corvallis, OR

Master of Science – Civil/Ocean Engineering December 2010 Oregon State University, Corvallis, OR

Master of Science – Ocean Engineering July 2005

Indian Institute of Technology-Madras (IITM), Chennai, India Bachelor of Engineering – Civil Engineering July 2002 Nagpur University, Nagpur, Maharashtra, India

PROFESSIONAL EXPERIENCE

Project Engineer – RE Vision Consulting LLC, Sacramento, CA October 2016 – February 2020 Project: “Control Optimization of WEC Devices Leveraging Real-Time Ocean Wave Prediction”.

• Experimental investigations using different wave measurement devices and development of a real-time wave prediction code framework to be used in an optimal control of different WEC devices/topologies. Engineering Responsibilities:

Numerical code development work:

- Development of state-of-the-art system dynamic models that support marine renewable energy projects.

- Optimization and validation of ocean wave prediction algorithms/code frameworks.

- Implementation of wave prediction algorithm within an advanced control framework using computationally efficient codes written in MATLAB.

- Development of a robust interface in MATLAB that seamlessly feeds in the data obtained from the measurement devices to the wave prediction algorithm in real-time.

Experimental investigations involving:

- Wave-tank testing of different WEC devices.

- Development of novel approaches to measure wave free-surface motion using different wave measurement buoys in real-time.

- Rigorous testing and system validation using long range serial communication applications requiring RF modems that transmit wave information in real-time.

Lead project team that performed several in-ocean wave measurement campaigns to enable robust application of controls at sea with suitable hardware (HW) and software (SW) integration and refinement of approaches using numerical modeling.

Developed technical content for grant proposals to secure external funding.

Publish reports and journal article(s) at various stages of project maturity. 2 Ravi Challa

Post-Doctoral Research Associate January 2015 – September 2016 Oregon State University, Corvallis, OR, U.S.A.

Engineering Responsibilities:

Performed basic and applied research related to fully coupled fluid-structure interaction (FSI) problems.

Design and model multiscale hydrodynamic impact problems on naval ships and high-speed boats.

Assist graduate student(s) in developing a numerical approach to predict hydrodynamic responses of wave energy converters (WECs).

Computational modeling of ocean waves using a Numerical Wave Tank (NWT) approach to validate FSI models.

Unified modeling, computation/calculations and numerical analysis techniques integrating deterministic and stochastic analytical methods, large-scale numerical and experimental wave-basin model simulations.

Mathematical modeling and analysis of wave impact problems in the form of wedge impact on water free-surface and breaking-wave impact on vertical walls.

Development of numerical models with improved water free-surface tracking techniques. Graduate Research Assistant January 2011 – December 2014 (PhD) Department of Civil and Construction Engineering September 2006 – December 2010 (MS) Oregon State University, Corvallis, OR, U.S.A.

Project: “Contact and Impact Fluid-Structure Interaction (FSI): Experimental, Numerical Modeling and Application to Practical Civil and Ocean Engineering Problems”.

• Systematically investigate the contact and impact FSI with experimental and numerical modeling procedures applied to various practical multi-physics ocean engineering problems. Significant components involve rigid, flexible and complex body contact and impact FSI analysis. Engineering Responsibilities:

Individual Contributor:

Worked in a team of highly skilled numerical modeling and design specialists.

Developed engineering problem-solving skills using numerical simulations (fully coupled FSI) involving mine burial (constitutive modeling involving fluid-soil-structure interaction), tsunami-structure interaction, rigid-object interaction with water free-surface/contact, and impact dynamics involving drop test modeling, flexible structure interaction with water free-surface involving dam break and low/high-filled fluid sloshing problems using advanced finite element codes such as LS-DYNA and Smoothed Particle Hydrodynamics (SPH).

Applied contact and impact FSI numerical modeling procedure to various practical multi-physics civil and ocean engineering problems.

Experimental and numerical investigations for a rigid-body contact and impact (drop tests), followed by numerical simulation and analysis of low and high-filled multi-physics sloshing phenomena in the LNG tank including air compressibility effect.

Evaluated performance of a finite-element (FE) based arbitrary Lagrangian-Eulerian (ALE) technique and a smoothed particle hydrodynamics (SPH) method by using a unified solution methodology and computational platform for the simulation of contact and impact of a fluid interacting with a flexible body.

Investigated numerical simulation and analysis of a complex body contact and impact (a fully pressurized surface effect ship (SES) bow finger seal motions).

Developed a state-of-the-art numerical modeling approach to measure the dynamic oscillations of the SES bow finger seals (solid mechanics) against a steady current and potentially quantify the scaling effects between various experiments.

Successfully completed a collaborative research project on FEA (strength assessment and fatigue analysis) on concrete armor units (A-Jacks/Concrete Dolo).

Project Leader:

Worked on several research projects sponsored by the Office of Naval Research (ONR) and Oregon Department of Transportation (ODOT).

Managed multiple research projects and delivered results under tight schedules and served as team leader in development of a National Science Foundation (NSF) proposal for a reconfigurable beach design and analysis. 3 Ravi Challa

Graduate Research Assistant August 2002 – August 2005 Department of Civil and Ocean Engineering

Indian Institute of Technology-Madras (IITM), India Project: “Water Entry Contact/Impact Dynamics of a Space Capsule”.

• Experimental investigation on a 1/6th Froude scale model of a Water Landing Object (WLO) in the wave basin

(drop tests) and validation of the experimental results using an FE based ALE technique and SPH method available in the state-of-the-art nonlinear dynamic finite element code (LS-DYNA). Engineering Responsibilities:

Project leader of the mission involving experimental design and numerical simulations.

Successfully delivered the experimental and numerical phase for the Indian Moon Mission (in collaboration with the Industrial Consultancy and Sponsored Research (ICSR) at IIT-Madras).

Reviewed literature and performed data collection and successfully executed the experimental phase.

Performed independent research in analyzing the experimental results using classical analytical approaches and numerical simulations of the water impact.

PROFESSIONAL MEMBERSHIPS

American Society of Civil Engineers (ASME), Member – Paid membership (open to all)

American Society of Mechanical Engineers (ASME), Member – Paid membership (open to all)

National Hydropower Association (NHA), Re Vision Consulting (company membership) TECHNICAL SKILLS

CAE/FEA/CFD/CAD software: LS-DYNA (with CFD-FSI), ANSYS, LS-PrePost, FEMB, MathCAD.

Operating Systems: Windows, Linux.

Programming Languages: MATLAB, familiar with C and Python.

Software: Proficiency in MS Word, Excel and PowerPoint.

Familiarity with serial communication modems: Peer-to-Peer (P2P)/Multipoint network.

Tools: MS-Office (familiarity with Windows workstations and Unix servers).

Technical document preparation using Microsoft Word. ACHIEVEMENTS & HONORS

Peer reviewer for ASME Journal of Offshore Mechanics and Arctic Engineering (OMAE).

Peer reviewer for ASCE Journal of Waterway, Port, Coastal, and Ocean Engineering.

Taught graduate level courses at Oregon State University - Dynamics of Ocean Structures, Nonlinear Finite Element Analysis to model complex fluid-structure-interaction systems and Theory of Plates and Shells.

Best technical poster at the Indian Geotechnical Conference (IGC) – India Chapter, Indore, Madhya Pradesh

(MP), India, December 2001.

Best technical paper at the Ocean Engineering Symposium for Renewable Energy during the 40th Anniversary celebrations of IIT-Madras, Chennai, India, November 1999. 4 Ravi Challa

List of Publications

Publications

Challa, R., Yim, S. C., 2019. “Fluid Impact Pressures on a Rigid Wall Including Air Compressibility Effect,” ASCE Journal of Engineering Mechanics (resubmitted).

Challa, R., Yim, S. C., 2017. “Finite Element and Smoothed Particle Hydrodynamics Modeling of Fluid- Flexible-Structure Interaction Using a Unified Computational Methodology,” ASME Journal of Offshore Mechanics and Arctic Engineering, doi:10.1115/1.4038939.

Challa, R., Yim, S. C., Idichandy, V. G., and Vendhan, C. P., 2014. “Rigid-Object Water-Surface Impact Dynamics: Experiment and Semi-Analytical Approximation,” ASME Journal of Offshore Mechanics and Arctic Engineering, 136(1), 011102, doi: 10.1115/1.4025653.

Challa, R., Yim, S. C., Idichandy, V. G., and Vendhan, C. P., 2014. “Rigid-Object Water-Entry Impact Dynamics: Finite-Element/Smoothed Particle Hydrodynamics Modeling and Experimental Calibration,” ASME Journal of Offshore Mechanics and Arctic Engineering, 136(3), 031102, doi: 10.1115/1.4027454.

Yim, S. C., Azadbakht, M., Challa, R., Lou, J., Mohtat, A., Newborn, D., and Zhang, Y., 2014. “Physical and Numerical Large-Scale Wave Basin Modeling of Fluid-Structure Interaction and Wave Impact Phenomena,” Journal of Marine Systems and Ocean Technology, 9(1), pp. 29-47. Conference Presentations

Mohtat, A., Challa, R., Yim, S. C., and Judge, C. Q. 2015. “Numerical Modeling of Hydrodynamic Impact and Local Slamming Effects,” 13th International Conference on Fast Sea Transportation (FAST), September 1-4, Washington, D.C., USA.

Newborn, D., Challa, R., and Yim, S.C. 2013, “Analysis of Surface Effect Ship Seal Mechanics by Experimental and Numerical Modeling,” 12th International Conference on Fast Sea Transportation (FAST), September 9-12, Amsterdam, Netherlands.

Challa, R., Newborn, D., and Yim, S.C., 2013, “Finite Element Contact/Impact Modeling Capability of Complex Surface Effect Ship Dynamics: Preliminary Assessment,” Proceedings of the 32nd International Conference on Ocean, Offshore and Arctic Engineering (OMAE), June 9-14, Nantes, France.

Yim, S. C., Azadbhakht, M., Challa, R., Lou, J., Mohtat, A., Newborn, D., and Zhang, Y., 2013, “Physical and Numerical Large-Scale Wave Basin Modeling of Fluid-Structure Interaction and Wave Impact Phenomena,” Proceedings of the Ten-Years LabOceano Celebration Workshop, April 29-30, Rio de Janeiro, Brazil.

Challa, R., Yim, S.C. 2012. “Current LS-DYNA Fluid-Structure-Sediment Contact/Impact Modeling Capability,” Proceedings of the 8th International Conference on Coastal and Port Engineering in Developing Countries (COPEDEC), February 20-24, Indian Institute of Technology Madras, Chennai, India.

Y. Zhang, Challa, R., and S.C. Yim, “A Study on Particle Finite Element and Smooth Particle Hydrodynamic Methods in Free-Surface Flow Modeling,” Particle 2011, II International Conference on Particle-Based Methods, Fundamentals and Applications, Barcelona, Spain, Oct. 26-28, 2011.

Challa, R., Idichandy, V.G., Vendhan, C. P., and Yim, S. C. 2010, “An Experimental study on rigid-object water- entry impact and contact dynamics,” Proceedings of the 29th International Conference on Ocean, Offshore and Arctic Engineering (OMAE), June 6-11, Shanghai, China.

Challa, R., Yim, S. C., Idichandy, V. G., and Vendhan, C. P. 2010, “Finite-Element and Smoothed Particle Hydrodynamics Modeling of Rigid-Object Water-Entry Impact and Contact Dynamics and Validation with Experimental Results,” Proceedings of the 29th International Conference on Ocean, Offshore and Arctic Engineering (OMAE), June 6-11, Shanghai, China.

Challa, R., Idichandy, V. G., and Vendhan, C. P. 2004. “Hydrodynamic analysis of a space capsule impacting water,” 3rd Indian National Conference of Oceans and Harbors (INCHOE), National Institute of Oceanography Goa, India, 2, pp. 516-522.

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