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Short Courses

This year’s 2021 OMAE Short Course offering will consist of the following topics and speakers:

* There is a deadline for course registration signup two weeks prior to the scheduled date. If there are insufficient registrants, the course may be cancelled. If there are enough early registrants, additional later registration is allowed.

 

Physics-Based Data-Driven Modeling and Machine Learning: Application to Marine/Offshore Engineering

June 17 & 18, 2021
10:00 am – 1:00 pm EDT

Instructors
Dr. Rajeev K. Jaiman,
Associate Professor, Department of Mechanical Engineering
University of British Columbia, Vancouver, Canada

Tutors: Rachit Gupta & Amir Chizfahm

Course Description:

Advances in high-performance computing (HPC) have empowered us to perform large-scale simulations for millions of variables in coupled fluid-structure systems involving complex geometries and multiphase flows. These high-fidelity simulations via coupled nonlinear partial differential equations (PDE) have been providing invaluable physical insight for the development of new designs and devices in marine/offshore engineering.  Despite efficient numerical methods and powerful supercomputers, state-of-the-art computational fluid dynamics (CFD) and coupled fluid-structure simulations are somewhat inefficient hence less attractive with regard to the design optimization, parameter space exploration and the development of control and monitoring strategies for marine and offshore structures.  In this short course, I will cover some of our recent developments to integrate and to complement the HPC-based high-fidelity computations with the emerging field of data science and machine learning. The primary focus of this course is: (i) to develop simple and efficient reduced-order models for the physical modeling of fluid-structure systems, and (ii) to explore the integration of projection-based model reduction with deep neural networks.  A series of canonical academic and industry test cases will be covered to elucidate the integration of standard CFD with model reduction and deep learning techniques for the prediction of vortex-induced loads and motion effects. Some efforts on the iterative optimization and feedback active control of unsteady wake flow and vortex-induced vibration will be explored. Such hybrid high-fidelity CFD with a data-driven computing framework is precisely aligned with the current marine/offshore industry needs on structural life prediction, feedback control and monitoring via digital twin.

You Will Learn:

  • Data-Driven Modeling of Physical Systems: Using the input and output data streams, participants will be able to build a dynamic state-space model in continuous-time and discrete-time domains for generic physical systems. For the stability analysis and control of coupled fluid-structure systems, they will be able to utilize data-driven modeling techniques such as eigensystem realization algorithm (ERA), dynamic mode decomposition (DMD), sparse identification of nonlinear systems, and Koopman operator theory.
  • Model Order Reduction: Participants will be able to reduce the order of the state-space model by using model reduction techniques based on balanced realization and proper orthogonal decomposition (POD) via the method of snapshots. Using the projection-based model reduction, they should be able to build some ideas to solve unsteady flows and fluid-structure interaction problems.
  • Machine Learning and Neural Networks: Participants will get some understanding of the nuts and bolts of supervised neural networks (feedforward and recurrent). They will understand selected neural network architectures (e.g., convolutional neural network) and will be exposed to current research efforts. Especially, they will acquire a general understanding of optimization strategies to guide training Deep Architectures and practical aspects of ML/DL software tools. They will get exposure to unsteady fluid flow predictions via hybrid POD/CNN and convolutional recurrent autoencoder networks.

Tentative Schedule:

DAY 1- June 17 (Thursday), 2021

  1. Introduction
    1. Representative marine/offshore engineering problems
    2. The essence of data-driven modeling
    3. Integration of physical models with data-driven computing
    4. Overview of Model Reduction and Machine Learning
  2. Projection-based Model Reduction
    1. Concept of Projection and Dimensionality Reduction
      1. Low-dimensional data-driven models
      2. State-space model representation
      3. Singular Value Analysis and Balanced Realizations
    2. Physics-Based Reduced-Order Models
      1. Proper Orthogonal Decomposition
      2. Method of Snapshots
      3. Dynamic Mode Decomposition
      4. Sparse Identification of Nonlinear Systems
    3. Nonlinear Model Reduction
      1. Concept of Empirical Interpolation
      2. Discrete Empirical Interpolation Method (DEIM)
    4. System Identification Techniques
      1. Dynamical systems, eigenvalues and projection
      2. Eigenvalue realization algorithm
  3. Hands on tutorial and examples

 

DAY 2- June 18 (Friday), 2021

  1. Machine Learning and Neural Networks
    1. A primer on machine learning
      1. Preliminaries of feed-forward and recurrent networks
      2. Supervised learning and classification problem
      3. Deep learning overview
      4. Convolutional neural networks and key techniques
    2. Physics and mathematics behind neural networks
      1. Deep learning for dynamical systems
      2. Physical-based neural networks
      3. Recurrent neural networks
    3. Practical aspects of deep learning
  2. Test cases and applications
    1. Unsteady wake dynamics and force decomposition
    2. Vortex-induced vibration
    3. Active feedback control of VIV
    4. Two-phase flow and wave-structure interaction
    5. Application to time-series prediction a short riser section

 

Practical approaches to modeling and control design for a wave energy converter

June 17 & 18, 2021
9:00am – 12:00pm EDT

Instructors
Dr. Ryan Coe

Dr. Giorgio Bacelli

Dr. Umesh Korde
 

Course Description:

The process to design, model, control, and test a wave energy converter (WEC) is still nascent and varies dramatically amongst practitioners. Factors from a wide range of sub-disciplines, such as naval architecture, electronics, hydraulics, robotics, dynamics, and control, all play important roles in this process. With so many competing factors, it is hard to know where to begin and which path(s) to follow. However, by abstracting the problem into a familiar framework, the important factors and concepts for WEC design become more clear. This workshop will introduce students to a set of practical tools that can be applied in engineering analyses of WECs, with specific attention focused on dynamics, control, signal processing, experimental design and analysis, and full-scale design. This course will begin with a review of the development of wave energy research and device design over the past 50 years. Subsequently, we will use multiple examples to illustrate a workflow for experimental testing, numerical model, and control design for WECs. The focus will be on methods and workflows that can be immediately applied to WEC engineering problems. The course will leverage experimental data collected during wave tank testing and include multiple interactive components in which students can work through examples in MATLAB.

You Will Learn:

Students will learn a theoretical foundation and set a tools that can be applied in WEC design, modeling, and control. Interactive examples will provide students with direct experience in applying the tools discussed during the class.

Schedule:

Day 1

0.25 hr

Introductions and course overview

0.75 hr

Modeling ocean waves and a wave energy converter

0.75 hr

Dynamical systems & control

0.75 hr

A history and future of WEC design and research

Day 2

1.5 hr

Case study: WaveBot

0.75 hr

Case study: FOSWEC

 

 

Dynamic Analysis of Floating Offshore Wind Turbines

June 19 & 20, 2021
8:00 am – 10:00 am EDT

Instructors
Dr. Erin Bachynski

Department of Marine Technology, NTNU

Course Description:

This course reviews several considerations related to design and operation of floating wind turbines. Fundamental concepts in aerodynamic (with focus on blade element/momentum theory) and hydrodynamic (with focus on first and second order radiation-diffraction and Morison-type models) load calculation are presented. The course addresses theoretical background and important practical considerations for structural response analysis combining the description of environmental conditions, computation of these load components, and inclusion of wind turbine control for ULS and FLS design check. A review of the state of the art of validation of commonly used engineering tools is provided.

You Will Learn:

• To explain the basic wind turbine components, and types of floating substructures, and their advantages and disadvantages,

• To identify key external loads on floating offshore wind turbines and understand the theory for their estimation,

• To understand and be able to critically assess state-of-the-art global dynamic analysis of offshore wind turbines, including interactions between the wind- and wave-induced loads and responses,

• To describe the stochastic variation in the wind and waves in short and long term, and how this affects the global responses of floating wind turbines.

Schedule:

Two 2-hour “live” sessions, focusing on examples, interactions, and discussions. Several short videos should be watched prior to the live sessions in order to provide the theoretical background for the live sessions.

Session

Topics

Videos to watch before the session:

Session 1

Introduction. Design criteria and rules. Design wind and wave conditions, wind and wave inputs. Introduction to aero-hydro-servo-elastic analysis.

Basic theory of wind turbine aerodynamics (ideal turbine without wake rotation, airfoil basics, BEM, engineering corrections). Time-domain dynamic analysis of floating structures. Structural modelling (FEM). Example results: decay tests.

Video 1.1: introduction to the module (2 min)
Video 1.2: review of floating wind turbine concepts (15 min)
Video 1.3: design conditions and integrated analysis (10 min)
Video 1.4: Description of the wind (10 min)
Video 1.5: Description of the waves (6 min)
Video 2.1: 1-D momentum theory (18 min)
Video 2.2: Airfoils (10 min)
Video 2.3: Structural dynamics (15 min)
Video 2.4: Time domain integration (10 min)

Session 2

Review of relevant hydrodynamic theories. Basics of wind turbine control. Coupled dynamic analysis of bottom-fixed and floating wind turbines under simultaneous wind/wave loads as well as control actions. Stochastic analysis of irregular wind and wave results. Rainflow counting, Palmgren-Miner.

Wind turbine faults. Non-operational conditions. Open source and commercial tools. Validation of aero-hydro-servo-elastic tools.

Video 3.1: Hydrodynamics of OWT (13 min)
Video 3.2: Introduction to wind turbine control (15 min)
Video 3.3: Response analysis intro (4 min)
Video 3.4: Basic definitions of statistical quantities (9 min)
Video 3.5: Introduction to fatigue calculation (8 min)
Video 4.1: Video 4.1: Introduction to faults and failures (10 min)
Video 4.2: Software overview, introduction to verification and validation (14 min)

 

 

Dynamics and Vibrations in Offshore Structures

June 26 & 27, 2021

8:00am – 11:30am EDT

 

Instructors

Dr. Junbo Jia

Aker Solutions, Norway

 

Prof. Bernt Johan Leira

Norwegian University of Science and Technology, Norway

Course Description

An understanding of the principles of dynamics and vibrations is important for assuring system integrity and operational functionality in different engineering areas. However, practical problems regarding dynamics are in many cases handled without success, despite large expenditures of investment. It is essential in approaching dynamic analysis and design that one develops an “intuition” to solve the relevant problems at hand; both academic knowhow and professional experience play equally important roles in developing such intuition. To meet the objectives above, this course aims to address a wide range of topics in the field of offshore structures, starting from fundamentals and moving on to relevant and practical engineering challenges and solutions. Special emphasis is placed on engineering applications that utilize state-of-the-art knowledge, the finite element method, relevant codes, probabilistic methods, and recommended practices. The course is primarily intended for industry professionals, researchers, and graduate students in offshore, civil, and marine engineering who desire an introduction to principles of dynamic analysis and design as well as those who are eager to learn advanced and efficient techniques used to mitigate vibrations for offshore as well as land-based structures.

 

You Will Learn:

(i) Engineering failures due to inappropriate accounting of dynamics; (ii) Newtonian dynamics;  (iii) Stochastic dynamics; (iv) Nonlinear dynamics; (v) Characterizing environmental loadings and responses; (vi) Dynamics in assessing different limit states (extreme, fatigue, etc.); (vii) Vibration mitigation measures.

 

Schedule

Day 1:

  • Engineering Significance of Dynamics and Vibrations (1 hour)
  • Fundamentals of Structural Dynamics and Vibrations (1.5 hours)
  • Damping (1 hour)

 

Day 2:

  • Stochastic Dynamics (1 hour and 45 minutes)
  • Nonlinear Dynamics (30 minutes)
  • Practical Mitigation Measures Against Dynamic and Impact Loading (1 hour and 15 minutes)
  • Q&A