Ｃomputational Study of Flow Past an Prolate Spheroid at Various Angles of Attack and High Reynolds Number

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基本資料

Project title

Code/計畫編號

MOST109-2221-E019-017

Translated Name/計畫中文名

長球體流場在不同攻角與高雷諾數下 RANS 計算解析

Project Coordinator/計畫主持人

Jiahn-Horng Chen

Funding Organization/主管機關

National Science and Technology Council

Department/Unit

Department of Systems Engineering and Naval Architecture

Website

https://www.grb.gov.tw/search/planDetail?id=13534292

Year

2020

Start date/計畫起

01-08-2020

Expected Completion/計畫迄

31-07-2021

Bugetid/研究經費

1177千元

ResearchField/研究領域

機械工程

國艦國造與潛艦國造為我國國防產業發展的三大主軸之一，其中潛艦國造允為我國世紀性大工程，將可帶領我國國防產業的躍升。長球體可視為理想化的潛艦外殼形狀，相關的水動力學分析不僅具有學術研究的價值，同時也具有先導性國防應用的意義。本研究旨在使用雷諾平均方程式（Reynolds-averaged Navier-Stokes equations），採用 k-omega 紊流模型，探討長軸與直徑比為 6:1 之長球體在高攻角入流下之流場特性，而為國內大型空蝕水槽之實驗作預備，本研究也將探討有限空間實驗條件下的水槽槽壁效應，而我們所採用的水槽尺寸為國立台灣海洋大學的大型空蝕水槽。本研究擬使用一年的時間完成以下的工作。1. 入流攻角為0度、5度、10度、20度、30度、45度、60度下的紊流流場計算與分析。2. 雷諾數分別為100,000 與 10,000,000兩個。其中前者已有實驗數據可比對，後者則為更高的雷諾數值，尚無任何實驗數據存在。3. 上述條件下，無限流域與有限水槽流域的流場特性比對。4. 我們的探討重點將放在流體運動在橢球體上的剝離現象、渦流現象、阻力特性等。5. 對於非穩態流場，我們將變化入流攻角，以線性函數與正弦函數從0度變化到60度，探討上述物理現象的變化。 The long-term program of Indigenous Warship Building and Indigenous Defense Submarine (IDS) has been one of three pillars of national defense industry. Among them, the IDS program will be a sparkling point which makes the technological leap of domestic defense industry possible.A prolate spheroid can be regarded as an idealized form of a submarine. The hydrodynamic analysis of flow past such a body has its own fundamental values and, at the same time, practical significances in the applications of defense research. The present proposal focuses on the flow development for a 6:1 prolate spheroid at various angles of attack by using a computational approach. The Reynolds-averaged Navier-Stokes (RANS) equations will be solved by CFD and the k-omega turbulence model will be adopted for turbulent effects. We will study both unbounded and confined flows past the ellipsoid. The latter will serve as the exploration of blockage effects to prepare future experimental studies of IDS program in the large cavitation tunnel at National Taiwan Ocean University. Therefore, the confined flow will be specifically specified as the flow in that cavitation tunnel.In this proposal, the following tasks will be conducted.1. Flow computations and analysis are conducted at the angles of attack of 0, 5, 10, 20, 30, 45, and 60 degrees.2. The specified Reynolds numbers of incoming flow based on the length of the long axis are 100,000 and 10,000,000. The results at the former Reynolds number can be compared with existing experimental data available in the literature. The latter represents flow at a much higher Reynolds number for which no experimental data are available now. The flow characteristics for different Reynolds number will be compared and discussed.3. Both unbounded and confined flows will be studied for the conditions listed in items 1 and 2.4. The physical phenomena which will be studied include three-dimensional flow separation, vortical flow behind the prolate spheroid, drag and lift.5. Unsteady flow computations for varying angles of attack of incoming flow from 0 to 60 degrees.

Keyword(s)

長球體
高攻角流場
紊流
三維流動剝離
阻力
空蝕水槽的槽壁效應
尾流
Prolate spheroid
flow at high angles of attack
turbulent flow
three-dimensional flow separation
resistance
blockage effect of cavitation tunnel
wake

DSpace CRIS

Ｃomputational Study of Flow Past an Prolate Spheroid at Various Angles of Attack and High Reynolds Number

基本資料

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