Dissertation/ Thesis
The Effects of Deployable Surface Topography Using Liquid Crystal Elastomers on Cylindrical Bodies In Flow
| العنوان: | The Effects of Deployable Surface Topography Using Liquid Crystal Elastomers on Cylindrical Bodies In Flow |
|---|---|
| المؤلفون: | Settle, Michael J., Jr |
| بيانات النشر: | University of Dayton / OhioLINK, 2023. |
| سنة النشر: | 2023 |
| المجموعة: | Ohiolink ETDs |
| Original Material: | http://rave.ohiolink.edu/etdc/view?acc_num=dayton1683048659500655 |
| مصطلحات موضوعية: | Aerospace Engineering, Aerospace Materials, Materials Science, Engineering, Mechanical Engineering, Liquid crystal elastomers, Active flow control, Controllable surface topography, Digital image correlation, Wind tunnel analysis on patterned cylindrical bodies in flow |
| الوصف: | Adaptive materials with programmable surface topography control can be utilizedfor selective boundary-layer tripping. Liquid crystal elastomers (LCE) have lately gainedsignificant attention to be leveraged to enable these changes via repeatable and controlledout-of-plane deformations. The LCE can be preferentially aligned with circumferentialpatterns through the thickness of the film, which yields a predictable conical out-of-planedeformation when thermally activated. These reversible and predictable deployments canbe utilized to develop a multifunctional surface designed for bodies in flow. This thesisconcentrates on the experimental research of LCE behavior for purposes of active flowcontrol via controlled surface topography. First, the deformations of the 12.7-mm diameterpatterned LCE samples were characterized using digital image correlation in a controlledpressure chamber under positive and negative gauge pressures. The LCE's performancewas highly dependent upon boundary conditions, specimen dimensions, and imprinteddefect location relative to the boundary conditions, thus leading to the refinement of theLCE formulation to allow for a higher modulus. Then, to exhibit the potential for flowcontrol, varying arrangements of representative topographical features were 3D-printedand characterized in a preliminary wind tunnel experiment using particle imagevelocimetry (PIV). Results demonstrated that a two-row arrangement of 1.5-mm featureheight produced an asymmetric wake about a 73-mm cylinder, reducing drag whilegenerating lift. Subsequently, a proof of concept model with active LCE elements wasfabricated and tested using a force-balance instead of PIV in a wind tunnel. The results ofthe conceptual model demonstrated that LCEs exhibit the necessary performance to be usedin flow control applications. |
| Original Identifier: | oai:etd.ohiolink.edu:dayton1683048659500655 |
| نوع الوثيقة: | Text |
| اللغة: | English |
| الاتاحة: | http://rave.ohiolink.edu/etdc/view?acc_num=dayton1683048659500655 |
| Rights: | unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
| رقم الانضمام: | edsndl.OhioLink.oai.etd.ohiolink.edu.dayton1683048659500655 |
| قاعدة البيانات: | Networked Digital Library of Theses & Dissertations |
| الوصف غير متاح. |