2 research outputs found
On the modulation of low-order roughnesses on the flow over low-order topographies
No full textThe impact of low-order roughness on low-order topographies was experimentally explored using high-resolution particle image velocimetry in a refractive-index-matching channel at Reynolds numbers Re = 40,000, based on the channel half height and the bulk velocity. The topographies consisted on 2D and 3D sinusoidal waves, which spanned most of the test section. The roughnesses also consisted on the same waveforms but one order of magnitude smaller than the topographies. We focused on 2D-2D and 3D-3D roughness-topography configurations. The flow statistics are compared with hydrodynamically smooth wavy topographies to get insight on the effects of the 2D and 3D roughnesses. Inspection of the flow statistics reveal that the low-order roughness induced changes in the velocity fluctuations near the wall; mean flow was not substantially modified. In particular, the Reynolds stress decomposition via quadrant analysis revealed that the 2D roughness reduced the sweeps and ejections in the 2D topography; however, negligible changes occurred in the 3D case. Inspection of the flow fluctuations with Proper orthogonal decomposition at various spatial regions revealed that the 3D roughness increased the complexity of the flow, attributed possibly to the generation of small-scale motions located within the troughs.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2021-05-01The student, Matias Colombo Baeza, accepted the attached license on 2019-04-24 at 12:20.The student, Matias Colombo Baeza, submitted this Thesis for approval on 2019-04-24 at 12:28.This Thesis was approved for publication on 2019-04-25 at 12:11.DSpace SAF Submission Ingestion Package generated from Vireo submission #13877 on 2019-08-22 at 16:23:50Made available in DSpace on 2019-08-23T20:48:25Z (GMT). No. of bitstreams: 3
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Previous issue date: 2019-04-25Embargo set by: Seth Robbins for item 112382
Lift date: 2021-08-23T20:48:32Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemLimited Restriction Lifted for Item 112382 on 2021-08-24T09:15:38Z
On the modulation of low-order roughnesses on the flow over low-order topographies
No full textThe impact of low-order roughness on low-order topographies was experimentally explored using high-resolution particle image velocimetry in a refractive-index-matching channel at Reynolds numbers Re = 40,000, based on the channel half height and the bulk velocity. The topographies consisted on 2D and 3D sinusoidal waves, which spanned most of the test section. The roughnesses also consisted on the same waveforms but one order of magnitude smaller than the topographies. We focused on 2D-2D and 3D-3D roughness-topography configurations. The flow statistics are compared with hydrodynamically smooth wavy topographies to get insight on the effects of the 2D and 3D roughnesses. Inspection of the flow statistics reveal that the low-order roughness induced changes in the velocity fluctuations near the wall; mean flow was not substantially modified. In particular, the Reynolds stress decomposition via quadrant analysis revealed that the 2D roughness reduced the sweeps and ejections in the 2D topography; however, negligible changes occurred in the 3D case. Inspection of the flow fluctuations with Proper orthogonal decomposition at various spatial regions revealed that the 3D roughness increased the complexity of the flow, attributed possibly to the generation of small-scale motions located within the troughs.LimitedAuthor requested closed access (OA after 2yrs) in Vireo ETD syste
