The Experts below are selected from a list of 30 Experts worldwide ranked by ideXlab platform

D.j. Eyres - One of the best experts on this subject based on the ideXlab platform.

  • Aft End Structure
    Ship Construction, 2012
    Co-Authors: D.j. Eyres
    Abstract:

    The cruiser Stern was for many years the favored Stern type for ocean going ships; however, today, most of these vessels have a transom Stern. A cruiser Stern presents a more pleasant profile and is hydrodynamically efficient, but the transom Stern offers a greater deck area aft, is a simpler construction, and can also provide improved flow around the Stern. Many forms of rudder are available and the type and form fitted is intended to give the best maneuvering characteristics. Both the shape of the Stern and the rudder type will dictate the form of the Stern Frame, and this will be further influenced by the required propeller size. Of particular importance at the after end are the arrangements which permit both the propeller shaft and the rudder stock to pierce the intact watertight hull. The safety of the ship may depend on these arrangements.

  • 21 – Aft End Structure
    Ship Construction, 2007
    Co-Authors: D.j. Eyres
    Abstract:

    Publisher Summary The cruiser Stern was for many years the favored Stern type for ocean going ships; however, today, most of these vessels have a transom Stern. A cruiser Stern presents a more pleasant profile and is hydrodynamically efficient, but the transom Stern offers a greater deck area aft, is a simpler construction, and can also provide improved flow around the Stern. Many forms of rudder are available and the type and form fitted is intended to give the best maneuvering characteristics. Both the shape of the Stern and the rudder type will dictate the form of the Stern Frame, and this will be further influenced by the required propeller size. Of particular importance at the after end are the arrangements which permit both the propeller shaft and the rudder stock to pierce the intact watertight hull. The safety of the ship may depend on these arrangements.

Yue Zong-ge - One of the best experts on this subject based on the ideXlab platform.

Lin Hui-chi - One of the best experts on this subject based on the ideXlab platform.

  • Development of a Wave-Damping Stern for a Container Ship
    2007
    Co-Authors: Lin Hui-chi
    Abstract:

    本研究主要著眼於船艉幾何形狀，就降低阻力為目標之優化設 計。本研究針對台灣國際造船公司所提供之CV1700 貨櫃船之 RD542_0船型，利用電腦輔助設計與參數化設計之方法進行船型變化 規劃，再使用計算流體力學方法進行流場之計算，計算過程採有限體 積法與結構化網格離散計算空間，以計算穩態具船舶周圍自由液面黏 性流場。在計算不同船艉幾何形狀流場前，先針對原型船進行流場計 算，因該貨櫃輪已有漢堡實驗水槽之實驗資料，藉由與實驗資料比對 來驗證。在所使用網格密度分別為一百萬點、兩百萬點與四百萬點 時，其與實驗值比對之誤差分別為-4.79%、-4.81%與-0.88%，計算結 果與實驗之誤差相當均在5%以內。而流場之局部物理性質（如流場 速度分佈、水面波形）和實驗值也相當接近。 接著進行不同船艉幾何形狀之流場計算，計算條件為裸船殼，漢 堡船模尺寸(縮尺比23.76)，弗勞德數(Froud Number)為0.25(相當於實 船船速20.1節)，姿勢為平浮。由本研究計算與台大水槽實驗結果，證 實新船型之規劃，在特定之吃水狀況下，有助於壓制船艉部之興波， 達成總阻力減低之成效。另外為了研究艉部船形系統化改變對於艉部 流場產生壓浪之效果，利用艉部幾何相關之參數艉框架縱向斜角與橫 剖面特性(呈S形狀之程度)與船艉鴨形艉延伸之長度產生了一系列之 2 船形，以作為貨櫃船艉部船形幾何設計參數化研究之基礎。In this research, we primarily focus on an optimal design of a wave-damping Stern for a container ship .To generate a basis for designing a new Stern form or to improve the hull form, a series of Stern by a parametric-design method is conducted on a container ship provided by a shipyard . Simultaneously , a CFD method is introduced to predict the ship resistance . The applized CFD method is validated by comparing with HSVA experimental results with numerical prediction .The margin of error is less then 5% for grids with 1 million cells grid .As the number of cell increases to 4 million , the margin of error further reduces to smaller than 1%. Both numerical prediction and experimental result obtain on the NTU towing tank indicate that the new Stern form is better than the basic form by reducing the crest of Stern wave. Besides , this research creates a series of hull forms by varing with Stern Frame angle longitudinally, crosswise with cross-section properties and the elongation of ducktail which are for the sake of researching on the wave-damping effect of the new Stern shape.第1 章 緒論..........................................................................................................4 第2 章 船型之規劃與繪製..............................................................................7 2.1. 船形變化規劃之構想................................................................................7 2.2. 線型繪製..................................................................................................11 2.3. 橫向剖面形狀(NPT1~NPT4)..................................................................14 2.4. 縱向艉框架之角度................................................................................15 第3 章 CFD數值方法與驗證........................................................................20 3.1. 統御方程式..............................................................................................20 3.2. 紊流模型..................................................................................................20 3.3. 數值方法..................................................................................................21 3.4. 船殼所受合力之計算..............................................................................22 3.5. 自由液面計算..........................................................................................22 3.6. 平行計算..................................................................................................24 3.7. 網格測試..................................................................................................24 3.8. 數值方法測試..........................................................................................28 3.9. 計算條件..................................................................................................30 3.10. 原型船計算之驗證..............................................................................31 3.9.1 不同尺寸之船模計算..................................................................31 3.9.2 考慮下沉量之流場計算..............................................................31 第4 章 台灣國際造船設計船型之計算.....................................................36 4.1 PT-1 與PT-2 .............................................................................................36 4.2 方形艉傾斜角度之影響..........................................................................36 4.3 設計吃水(8.5m)下之NPT-104 與RD5421A0.........................................38 4.4 實際吃水(8.9m)下之NPT-104 與RD5421A0.........................................40 4.5 實際吃水(8.9m)下之RD542_1、RD5421A0 與RD542_0 ....................42 4.6 台灣國際造船船型之CFD與實驗比對..................................................44 第5 章 新船型之計算......................................................................................48 5.1. 8.9 米吃水之計算....................................................................................48 5.2. 9.49 米吃水之計算..................................................................................54 5.2.1. RD542_0、RD542_1、NPT-104......................................................54 5.2.2. NPT-1 系列........................................................................................59 5.2.3. NPT-2 系列........................................................................................60 5.2.4. NPT-3 系列........................................................................................61 5.3. 8.36 米吃水之計算..................................................................................63 5.3.1. NPT-1 系列........................................................................................66 5.3.2. NPT-2 系列........................................................................................67 II 5.3.3. NPT-3 系列........................................................................................67 5.3.4. WDA船型..........................................................................................68 5.4. 小結..........................................................................................................71 第6 章 鴨形艉延伸長度.................................................................................73 5.1. 8.9 米吃水之計算....................................................................................73 6.1.1. NPTX-4 系列.....................................................................................74 6.1.2. RD542_1 系列...................................................................................76 6.1.3. RD542_0 系列...................................................................................78 5.2. 8.633 米吃水之計算................................................................................82 6.2.1. NPTX-4 系列.....................................................................................82 6.2.2. RD542_1 系列...................................................................................84 5.3. 9.49 米吃水之計算..................................................................................87 6.3.1. RD542_1 系列...................................................................................87 第7 章 結論與建議..........................................................................................90 7.1. 結論..........................................................................................................90 7.2. 建議與未來方向......................................................................................92 附表............................................................................................................................95 附圖..........................................................................................................................11

C.b. Barrass - One of the best experts on this subject based on the ideXlab platform.

  • Types of power in ships
    Ship Design and Performance for Masters and Mates, 2004
    Co-Authors: C.b. Barrass
    Abstract:

    This chapter is designed to illustrate types of power in ships. When a ship generates a certain power within the engine room, this power will be transmitted along the propeller shaft and eventually to the tips of the propeller blades. There will be several losses of power enroute. All powers today are measured in kW. The power obtained from the ship model tests is known as the tow-rope power or the naked effective power. When tested, the towed ship model has a smooth clean hull with no appendages such as bossing, rudder, propeller, or bilge keels. Due to the propeller revolving within the Stern Frame, a vacuum is created. This causes a slight loss in the hull efficiency of the ship. The proportion or percentage relating the thrust power and the delivered power is the propeller efficiency. This percentage can be as high as 75% for some ships and as low as 60% for vessels such as supertankers. This chapter gives numerous examples that illustrate types of power in ships.

  • Chapter 20 – Ship vibration
    Ship Design and Performance for Masters and Mates, 2004
    Co-Authors: C.b. Barrass
    Abstract:

    Publisher Summary This chapter is designed to elucidate the concept of ship vibrations. It begins with explaining the terminology associated with vibrations. One of the main causes of vibration on ships is due to unbalanced forces where reciprocating machinery is fitted. Forces may be present due to forcing impulses in an internal combustion engine. Diesel engines can cause problems due to their required rpm being close to the natural hull frequency. Steam turbine machinery, due to having no unbalanced parts, cause little or no vibration problems of this type. Most vibration problems on ships can be traced to the propeller. This may be because of the following: irregular flow towards the propeller disc area, damaged propeller, unbalanced new propeller, propeller is too large for the aperture adjacent to the Stern Frame and the rudder, pitch variation from propeller root to propeller tip varying slightly from blade to blade, propeller has wrong number of blades and so produces resonance with another frequency linked with the vessel. A ship will vibrate due to the pounding effect at the forward end and also due to wave frequency acting at the same frequency as that of the hull. This type of vibration is known as “whipping” and is experienced mostly on fast container ships.

  • Performance enhancement in ship-handling mechanisms
    Ship Design and Performance for Masters and Mates, 2004
    Co-Authors: C.b. Barrass
    Abstract:

    Constant research and development are being made to improve the performance of ships. This chapter discusses performance enhancement in ship-handling mechanisms. Becker twisted rudder is designed to greatly reduce rudder cavitation and to improve the maneuverability performance of a full spade rudder. With the concept of Schilling VecTwin rudders, two rudders operate independently behind a single propeller. Stern fins are fins or strips of steel welded around the Stern Frame of a ship. The idea is that these welded fins will direct water into the propeller disc and thus improve the efficiency of the propeller. These are cheap to fit and retrofit. Claims of up to 6% power savings have been made for full-form and medium-form hulls. Hinged tail flap in rudder can cause the turning circle diameter to be halved. The main advantage of bulbous bows is the gain in speed for sinular input of engine power. Stern tunnel is built over the propeller helping to ensure that the propeller is kept sufficiently immersed when vessel is at ballast drafts. It is good for dampening vibration forces, especially where the propeller diameter is large. Retrofits improve the day-to-day performance of a ship or possibly leading to a reduction in operational costs. This chapter discusses these ship handling mechanisms alongwith others.

Erwin Van Nieuwenhuyse - One of the best experts on this subject based on the ideXlab platform.

  • The SmeltCam.
    2013
    Co-Authors: Frederick Feyrer, Donald Portz, Darren Odum, Ken B. Newman, Ted Sommer, Dave Contreras, Randall Baxter, Steven B. Slater, Deanna Sereno, Erwin Van Nieuwenhuyse
    Abstract:

    Upper panel is a diagram of the SmeltCam showing (A) net cowling and bow Frame, (B) sealed electronics compartment, (C) Stern Frame, (D) ballast hull and (E) top and bottom vision tube covers. Bottom panel is a photograph of the SmeltCam being deployed from a research vessel.