Date of Award

2016

Degree Type

Thesis

Degree Name

Master of Science in Ocean Engineering

Department

Ocean Engineering

First Advisor

Jason Dahl

Abstract

Validation and verification of numerical experiments require data with which to compare the results. In particular, hybrid methods that involve grid interfaces between multiple numerical solutions on submerged boundaries or at the free surface require volumetric measurements for validation. In this study, two methods to obtain a comprehensive data set including volumetric three dimensional, three component (3D3C) fluid velocities, free surface profiles and drag force are com- pared for accuracy and economy. For the first method, a NACA 0012 surface piercing foil is evaluated at Froude numbers 0:19, 0:37 and 0:55. Velocity measurements are obtained using Stereo Particle Image Velocimetry (SPIV) with the interrogation plane parallel to the chord line of the foil. Free surface profiles are obtained using a GoPro camera positioned to observe the intersection of the free surface and the laser sheet. Force data is obtained through a load cell mounted on the tow carriage. The second method positions the SPIV interrogation plane perpendicular to the chord of the foil such that the volume is sliced transversely while the foil passes through the plane in time. Surface elevations for this method are again measured with a GoPro, mounted to capture the intersection of the laser sheet and the free surface. The transverse method is examined at Froude number 0:37. Results are presented based on the flow field statistics and the fundamental features of the data sets are compared using dynamic mode decomposition. Comparison between the two methods are made qualitatively, as well as quantitatively using RMSE and Dynamic Mode Decomposition. The difference between the two methods is less than 10% RMSE.

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