Student: Christopher Callahan-Dudley
Area: Ocean Engineering
Professor/Sponsor: Professor Simo Makiharju
Mentor: Bradley Peifer
Research Project Title: Air Layer on Superhydrophobic Surface for Frictional Drag Reduction
Abstract
Student: Christopher Callahan-Dudley
Professor/Sponsor: Professor Simo Makiharju
Mentor: Cody Tecsan
Research Project Title: Air Layer on Superhydrophobic Surface for Frictional Drag Reduction *continuation of research reported in the paper of the same name by B. C. Peifer, C. Callahan-Dudley, and S. A. Makiharju (2018)
Abstract:
Air Layer Drag Reduction (ALDR) on large vessels is shown to reduce frictional drag significantly at the cost of large compressors to supply required flux. A superhydrophobic surface (SHS) has been shown to enable reduced frictional drag in the laboratory, but its benefits are lost if gas trapped in microscopic air pockets (plastrons) on the surface are lost due to diffusion or entrainment. Furthermore, durability of a SHS and its effectiveness at high Reynolds numbers is also still a topic of research. Work already done has qualitatively shown a significant reduction in the gas flux required to maintain a stable air layer on SHS for the purposes of frictional drag reduction at Reynolds numbers up to Rex =5.1×106. Research was carried out to quantify and confirm the earlier findings, in addition to progress towards measuring actual drag reduction and allow for testing at higher Reynolds numbers. Modifications to the void fraction impedance probes used during initial testing allowed additional testing to quantitatively show an average ~50% reduction in flux requirements for stable air layer maintenance. Additional work has gone in to the design of a drag measurement plate to be built into the test model which will allow direct measurement of frictional drag, confirming that the reduction seen with a superhydrophobic surface air layer coating is comparable with that seen in traditional air layer drag reduction testing. This measurement plate was designed to directly measure the frictional drag experienced by the test section during testing and will be operated first without any air layer or superhydrophobic coating to ensure that frictional drag measured closely matches that seen in current research. The SHS coating will then be applied and tested at difference flux rates, allowing for a direct comparison with traditional modes. We hope to show that frictional drag reduction with SHS and at reduced flux rates is similar to that seen with conventional ALDR methods. An acoustic velocity profiler is also in the process of being implemented to allow for a direct measurement of the velocity profile near the model (wall), in an effort to confirm operating assumptions. Lastly, modifications to the high-speed carriage located at the Richmond Field Station are ongoing, to provide a safe and stable test platform to allow model experiments at higher Reynolds numbers than were previously achievable. Future work hopes to use the current progress to show that SHS combined with ALDR drastically reduce the energy and cost requirements of traditional systems and provide an affordable means to achieve fuel savings and reduce environmental impact in the shipping industry.
Student: Shayan Javaherian
Professor/Sponsor: Professor Reza Alam
Mentor: Dr. Mohsen Saadat
Research Project Title: CalSat
Abstract:
The purpose of this research is to make underwater wireless communication possible by using ROVs and laser tractions. The calsat project is consist of two different version which they call CalSat 1 and CalSat 2. For CalSat 1 the purpose of this project is to modification of controls of two submarine model to carry out the proof of concepts of underwater optical communication using a swarm of autonomous underwater vehicles. For CalSat 2 we made our own ROV that is an Agile and robes underwater platform used for underwater communication by using laser tractions. I widely work on design, prototyping, and manufacturing of CalSat 2. CalSat 2 Has different versions which each one of them developed and improved based on the previous version. Different version of CalSat 2 are as following: CalSat 2A, CalSat 2B, CalSat 2C, CalSat 2D. Following pictures are for CalSat 2C while testing for leakage and performance in O’Brien facility at UC Berkeley.
Student: Stephanie Mah
Professor/Sponsor: Professor Reza Alam
Research Project Title: Actuated Absorber for Ocean Wave Energy Converter
Abstract
Student: Keyvan Taghizadehasl
Area: Design, Ocean Engineering
Professor/Sponsor: Professor Reza Alam
Mentor: Dr. Mohsen Saadat
Research Project Title: Design, Manufacturing and Testing of CALSAT 2.0 (Unmanned Underwater Drone)
Abstract