碩士 / 國立臺灣大學 / 農業工程學研究所 / 87 / Abstract
This study carried out a hydraulic modeling test about three kinds of fundamental fishways (pool-weir fishways, pool-weir-orifice fishways and vertical slot fishways) in detail. The model dimension almost approach the prototype dimension (experimental fishways was performed in a 1m wide flume and the total length is 7m. the height of the weirs is 0.4m.) Experiments were performed with slope of 5% and several flow rates from 0.002∼0.063cms. The flow fields were recorded by the electromagnetic three-dimensional flow velocity instrument, and the probe of hydraulic characteristic were proceeding. Many meaningful and practical results were obtained. Rerettably, for lack of the information of native fish behavior, this thesis only present the result of analysis about the flow field and hydraulic characteristic. Expect, there will be a related study about native fishes make use of these fishways. And the flow field and velocity data of the thesis can supply for making quantitative analysis.
Found from the study of the poor-weir fishways, for the plunging flow regime (sharp-crested weirs that weir nappe is not areated), the average discharge coefficient (Cd) of all baffles is 0.725. The formula which was established by Rajaratnam et al. (1988) to predict the transition from plunging to surface streaming state. The suitability of the formula should be made a thorough inquiry at different model dimensions.
Found from the study of the pool-orifice and pool-weir-orifice fishways, the center velocity of each orifice between the first and the last baffle can be estimated by √(2gΔh) . After a part of the flow over the weirs, in addition to obtain lower and steadier orifice velocity, it increases one passageway. This should be a better design of fishway.
Found from the study of the vertical slot fishways, the maximum vertical slot velocity near to the base can be estimated approximately by √(2gΔh) .
| Identifer | oai:union.ndltd.org:TW/087NTU00404025 |
| Date | January 1999 |
| Creators | Chia-Yu Lin, 林家愈 |
| Contributors | Hung-pin Huang, 黃宏斌 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 190 |
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