13.42: Design Principles for Ocean Vehicles Spring 2005: T/R 9:30-11:00 Prof. Alex Techet Design Principles for Ocean Vehicles • “Vehicles” – Surface ships, underwater vehicles, and offshore platforms • “Design Principles” – Tools for analyzing system dynamics 1 Image of drilling platform removed for copyright reasons.Courtesy of U.S. DOE. Courtesy of NOAA. Underwater Vehicles Surface Vessels 2 Photo courtesy of Steven Jayne.Offshore Platform Genesis Spar Platform Photos of Genesis Spar Oil Platform removed for copyright reasons. Please See: http://www.offshore-technology.com/projects/genesis/. 3 Courtesy of U.S. DOE.Basic “Recipe” • Fundamental Math & Science v – Newton’s 2nd Law, F = aM v – Conservation of Angular Momentum – Basic Fluid Mechanics • Idealized System Ship Heaving in waves Æ Mass Spring Dashpot system • Mathematical Model && ( &( (t xM ) + t x B ) + Cx (t ) = t F ) • Behavior Prediction – System analysis “tools” Tools for Design • Linear systems analysis • Fourier Transforms, Transfer Function • Probabilistic forecasting extreme events (such as the 100 year wave and water on deck) • Wave forces on floating bodies • Added mass and damping forces • Equations of motion of a vessel in waves 4Courtesy of JPL. FIGURE 1. Wave energy spectra. Red text indicates wave generation mechanisms and blue text indicates damping/restoring forces.Hydrodynamic Forces on Vessels • Linear wave theory • Strip theory – Added mass!!! • Wave forces on bodies • Viscous forces on bodies: – Skin Friction Drag – Vortex shedding, Vortex induced vibrations • Viscous damping Figure by MIT OCW. 6 xzySign convention for translatory & angular displacementsη3η4η1η2η6η5η1 = surgeη2 = swayη3 = heaveη4 = rollη5 = pitchη6 = yawShip Motions13.42 Organization• Instructor: • Grading – Professor Alexandra Techet –50% Exams –15% Homework – 35% Labs (2) + Project • Homeworks – Due weekly on Thursdays
View Full Document
Unlocking...