Hydrodynamic Drag on Streamlined Projectiles and Cavities

Handle URI:
http://hdl.handle.net/10754/609515
Title:
Hydrodynamic Drag on Streamlined Projectiles and Cavities
Authors:
Jetly, Aditya ( 0000-0002-7835-1527 )
Abstract:
The air cavity formation resulting from the water-entry of solid objects has been the subject of extensive research due to its application in various fields such as biology, marine vehicles, sports and oil and gas industries. Recently we demonstrated that at certain conditions following the closing of the air cavity formed by the initial impact of a superhydrophobic sphere on a free water surface a stable streamlined shape air cavity can remain attached to the sphere. The formation of superhydrophobic sphere and attached air cavity reaches a steady state during the free fall. In this thesis we further explore this novel phenomenon to quantify the drag on streamlined shape cavities. The drag on the sphere-cavity formation is then compared with the drag on solid projectile which were designed to have self-similar shape to that of the cavity. The solid projectiles of adjustable weight were produced using 3D printing technique. In a set of experiments on the free fall of projectile we determined the variation of projectiles drag coefficient as a function of the projectiles length to diameter ratio and the projectiles specific weight, covering a range of intermediate Reynolds number, Re ~ 104 – 105 which are characteristic for our streamlined cavity experiments. Parallel free fall experiment with sphere attached streamlined air cavity and projectile of the same shape and effective weight clearly demonstrated the drag reduction effect due to the stress-free boundary condition at cavity liquid interface. The streamlined cavity experiments can be used as the upper bound estimate of the drag reduction by air layers naturally sustained on superhydrophobic surfaces in contact with water. In the final part of the thesis we design an experiment to test the drag reduction capacity of robust superhydrophobic coatings deposited on the surface of various model vessels.
Advisors:
Samtaney, Ravi ( 0000-0002-4702-6473 )
Committee Member:
Thoroddsen, Sigurdur T ( 0000-0001-6997-4311 ) ; Mishra, Himanshu ( 0000-0001-8759-7812 ) ; Vakarelski, Ivan Uriev ( 0000-0001-9244-9160 )
KAUST Department:
Physical Sciences and Engineering (PSE) Division; Mechanical Engineering Program
Program:
Mechanical Engineering
Issue Date:
19-Apr-2016
Type:
Thesis
Appears in Collections:
Theses; Physical Sciences and Engineering (PSE) Division; Mechanical Engineering Program

Full metadata record

DC FieldValue Language
dc.contributor.advisorSamtaney, Ravien
dc.contributor.authorJetly, Adityaen
dc.date.accessioned2016-05-17T05:59:58Zen
dc.date.available2016-05-17T05:59:58Zen
dc.date.issued2016-04-19en
dc.identifier.urihttp://hdl.handle.net/10754/609515en
dc.description.abstractThe air cavity formation resulting from the water-entry of solid objects has been the subject of extensive research due to its application in various fields such as biology, marine vehicles, sports and oil and gas industries. Recently we demonstrated that at certain conditions following the closing of the air cavity formed by the initial impact of a superhydrophobic sphere on a free water surface a stable streamlined shape air cavity can remain attached to the sphere. The formation of superhydrophobic sphere and attached air cavity reaches a steady state during the free fall. In this thesis we further explore this novel phenomenon to quantify the drag on streamlined shape cavities. The drag on the sphere-cavity formation is then compared with the drag on solid projectile which were designed to have self-similar shape to that of the cavity. The solid projectiles of adjustable weight were produced using 3D printing technique. In a set of experiments on the free fall of projectile we determined the variation of projectiles drag coefficient as a function of the projectiles length to diameter ratio and the projectiles specific weight, covering a range of intermediate Reynolds number, Re ~ 104 – 105 which are characteristic for our streamlined cavity experiments. Parallel free fall experiment with sphere attached streamlined air cavity and projectile of the same shape and effective weight clearly demonstrated the drag reduction effect due to the stress-free boundary condition at cavity liquid interface. The streamlined cavity experiments can be used as the upper bound estimate of the drag reduction by air layers naturally sustained on superhydrophobic surfaces in contact with water. In the final part of the thesis we design an experiment to test the drag reduction capacity of robust superhydrophobic coatings deposited on the surface of various model vessels.en
dc.language.isoenen
dc.subjectHydrodynamicen
dc.subjectDragen
dc.subjectCavitiesen
dc.subjectProjectilesen
dc.titleHydrodynamic Drag on Streamlined Projectiles and Cavitiesen
dc.typeThesisen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentMechanical Engineering Programen
thesis.degree.grantorKing Abdullah University of Science and Technologyen_GB
dc.contributor.committeememberThoroddsen, Sigurdur Ten
dc.contributor.committeememberMishra, Himanshuen
dc.contributor.committeememberVakarelski, Ivan Urieven
thesis.degree.disciplineMechanical Engineeringen
thesis.degree.nameMaster of Scienceen
dc.person.id133913en
All Items in KAUST are protected by copyright, with all rights reserved, unless otherwise indicated.