2026-09-19T03:42:28Zhttps://dspace.mit.edu/server/oai/request

oai:dspace.mit.edu:1721.1/1237492021-07-05T14:03:20Zcom_1721.1_7582com_1721.1_7581col_1721.1_131023

Michael Triantafyllou. Kotidis, Miranda. Massachusetts Institute of Technology. Department of Mechanical Engineering. Massachusetts Institute of Technology. Department of Mechanical Engineering 2020-02-10T21:41:16Z 2020-02-10T21:41:16Z 2019 2019 https://hdl.handle.net/1721.1/123749 1138947251 Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019 Cataloged from PDF version of thesis. Includes bibliographical references (pages 57-58). As underwater vehicles become increasingly versatile and capable, bio-inspired propulsion systems are becoming a viable possibility for future vehicles. In particular, flapping foil actuators are promising in their abilities for propulsion and maneuvering. Current underwater vehicles rely on propellers, which form a jet wake to produce propulsion forces, and, as such, experience an inherent delay between the movement of the propeller and the vehicle feeling a propulsive force. To mitigate this shortcoming, flapping foils were moved in swift, one-time strokes to produce large, transient forces in still water to produce propulsive and/or maneuvering forces almost instantaneously. Previous work produced trajectories, characterized by heave and pitch motions, for which the lift and thrust profiles were confirmed. These strokes take advantage of added mass/inertial effects to produce propulsive forces useful for maintaining position or orientation or for precise maneuverability. Various novel combinations of heave and pitch motions were tested and dye visualization was performed with a custom wing to elucidate the wake and vortical structures produced by these strokes. by Miranda Kotidis. S.M. S.M. Massachusetts Institute of Technology, Department of Mechanical Engineering 58 pages eng Massachusetts Institute of Technology MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission. http://dspace.mit.edu/handle/1721.1/7582 Mechanical Engineering. Experiments with impulsive motion of a foil to generate large lift and thrust forces Thesis application/pdf 2020-02-10T21:41:16Z Publication Master MechE unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="456fcb99-e9b7-4a90-86e4-66f6c21440bc"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Experiments with impulsive motion of a foil to generate large lift and thrust forces</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2019</PublicationDate> <Authors> <Author> <DisplayName>Kotidis, Miranda.</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Mechanical Engineering.</Keyword> <Abstract>As underwater vehicles become increasingly versatile and capable, bio-inspired propulsion systems are becoming a viable possibility for future vehicles. In particular, flapping foil actuators are promising in their abilities for propulsion and maneuvering. Current underwater vehicles rely on propellers, which form a jet wake to produce propulsion forces, and, as such, experience an inherent delay between the movement of the propeller and the vehicle feeling a propulsive force. To mitigate this shortcoming, flapping foils were moved in swift, one-time strokes to produce large, transient forces in still water to produce propulsive and/or maneuvering forces almost instantaneously. Previous work produced trajectories, characterized by heave and pitch motions, for which the lift and thrust profiles were confirmed. These strokes take advantage of added mass/inertial effects to produce propulsive forces useful for maintaining position or orientation or for precise maneuverability. Various novel combinations of heave and pitch motions were tested and dye visualization was performed with a custom wing to elucidate the wake and vortical structures produced by these strokes.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>