Journal article
Vortical Structures and Instability Analysis for Athena Wetted Transom Flow with Full-Scale Validation
Journal of fluids engineering, Vol.134(3), pp.31201-18
03/01/2012
DOI: 10.1115/1.4006173
Abstract
Vortical structures and associated instabilities of appended Athena wetted transom flow in full-scale conditions are studied using DES to explain the source of dominant transom flow frequency, including verification and validation using full-scale experimental data. The results are also compared with model-scale bare and appended hull predictions and experiments. The grid used for the validation is sufficiently fine as it resolves 70% and 91% of the experimental inertial subrange and turbulent kinetic energy values, respectively. The model-scale bare and appended hull resistance predictions compare within 2.5%D and 5.4%D of the experimental data D, respectively. The full-scale appended hull resistance predictions compare within 4.2%D of the extrapolated data using the ITTC line. The averaged comparison error of the full-scale transom wave elevation mean, RMS and dominant frequency predictions and the experimental data is 8.1%D, and the predictions are validated at an averaged 11.2%D interval. The transom wave elevation unsteadiness is attributed to the Karman-like transom vortex shedding as both show the same dominant frequency. The Karman-like instability shows St = 0.148 for the bare hull and St = 0.103 ± 4.4% for model- and full-scale appended hull. The appended hull simulations also predict: horseshoe vortices at the juncture of rudder-hull with St = 0.146 ± 3.9% and strut-hull with St = 0.053 ± 2%; shear layer instability at the strut-hull intersection with St = 0.0067 ± 3%; and unsteady sinkage and trim induced by transom vortex shedding with St = 2.19. The instabilities do not show significant variation on scale, propeller or motions. The bare hull simulation also predicts flapping-like instability in the wake with St = 0.144.
Details
- Title: Subtitle
- Vortical Structures and Instability Analysis for Athena Wetted Transom Flow with Full-Scale Validation
- Creators
- Shanti Bhushan - Center for Advanced Vehicular Systems, 200 Research Blvd., Mississippi State University, Starkville, MS, 39759Tao Xing - Department of Mechanical Engineering, Engineering Physics, Room 324F, PO Box 440902, University of Idaho, Moscow, ID, 83844-0902Frederick Stern - IIHR-Hydroscience & Engineering, C. Maxwell Stanley Hydraulics Laboratory, The University of Iowa, Iowa City, IA, 52242-1585
- Resource Type
- Journal article
- Publication Details
- Journal of fluids engineering, Vol.134(3), pp.31201-18
- Publisher
- ASME
- DOI
- 10.1115/1.4006173
- ISSN
- 0098-2202
- eISSN
- 1528-901X
- Language
- English
- Date published
- 03/01/2012
- Academic Unit
- Mechanical Engineering; IIHR--Hydroscience and Engineering
- Record Identifier
- 9984064112202771
Metrics
16 Record Views