Some Aspects of Submarine Design Essay Example for Free

Some Aspects of Submarine Design Essay The history of submarines shows there were two significant advances in the performance of submarines, which occurred after full scientific studies were undertaken. The first was by the Germans at the end of World War II when they produced the Type 21, which could have upset the balance in the U-Boat campaign if it had arrived earlier. The second was by the US Navy with Albacore which had a submerged speed of over 30 knots. To neglect full scientific studies would be a serious mistake in the design of any future replacement submarine. Design is shown to be like a jigsaw puzzle where altering one piece requires alterations in all surrounding features to make a workable complete design. The basis of improved hydrodynamic features is discussed. A new nose shape is presented which should improve the performance of the forward passive sonar up to operational speeds. Other major sources of resistance may be improved. It is proposed a first major step should be to establish the detailed performance of Collins using wind tunnels and computational fluid dynamics which will serve as the comparative foundation for any new design. RELEASE LIMITATION Approved for public release Published by DSTO Platforms Sciences Laboratory 506 Lorimer St Fishermans Bend, Victoria 3207 Australia Telephone: (03) 9626 7000 Fax: (03) 9626 7999 Â © Commonwealth of Australia 2004 AR-013-204 October 2004 APPROVED FOR PUBLIC RELEASE Some Aspects of Submarine Design Part 1. Hydrodynamics Executive Summary The history of submarines subsequent to the first truly operational vessel, Holland, launched in 1899, showed two significant advances as opposed to steady incremental developments. These resulted from full scientific studies of all the problems. The first of these advances was made by the Germans at the end of World War II, when they produced the Type 21 which had major improvements in range and battery time while their underwater speed increased to 18 knots compared to 5 knots on previous vessels. Design diving depth was increased dramatically. They could operate below the Allies submarine defence weapon systems. The second advance was made by US designers who produced Albacore in 1953 with a shape suited to full underwater operation. Its length-tobeam ratio was only 7. 7 and top underwater speed was 33 knots. The drag coefficient was only 0. 1 compared to 0. 35 on previous submersible designs. It is clear that scientific studies should be a starting point for any future submarine design. A review of the literature covers priorities in design and shows how enhancement of one feature interacts with other features and may even result in an overall loss of performance despite the perceived advantage of the enhanced feature. Hydrodynamic aspects are then discussed starting with the shape and reasons why a length-to-beam ratio of about 7. 5 gives the minimum resistance. All features affecting the resistance are discussed including the boundary layer, laminar flow, transition, turbulence and separation and how the flow over the principle passive sonar should be as quiet and smooth as possible. Added resistance from sails, masts, snorkels and appendages need careful streamlining and attention in design. A proposed profile of a new submarine is presented which has the passive sonar far forward in the streamlined nose with the torpedo tubes positioned further aft. It should be a quieter vessel with more effective sonars. The profile requires shortening to reduce the displacement and then the internals need rearranging. The design process then begins, which is iterative. In order to proceed with such concepts it is vital to have a database. Our current submarine, the Collins class, should be the base from which all changes and proposals are measured. It is suggested detailed wind tunnel studies should be undertaken concurrently with computational fluid dynamic (CFD) evaluations. The results should then be compared with full scale trials to establish propeller efficiencies and roughness factors as well as the contributions for each feature, hull, sail, control fins, masts and snorkels, flood openings and others. This database will allow more precise comparisons for any improvements which may be considered in a future design. Author Prof. Peter Joubert (OAM) Contractor Maritime Platforms Division P. N Joubert, a World War II fighter pilot, after demobilisation from the RAAF, studied aeronautical engineering at Sydney University. He then joined CSIRO, where he designed a radio controlled meteorological glider. Subsequently he was appointed as a lecturer in mechanical engineering at Melbourne University specialising in fluid mechanics. In 1954 he attended the MIT where he built and tested high-speed catamarans in the towing tank. At Melbourne University he built a new wind tunnel and much research was initiated and conducted there. He has authored over 120 scientific papers, most of them in fluid mechanics, boundary layers, roughness, and vortices and recently with a PhD student, the flow about a submarine body in a turn. Over the years he has received many research grants including one from the US Navy. His work with his students and colleagues is recognised internationally such as by the General Motors Research Laboratories and other international ship research bodies. He has been studying flow patterns on submersibles since 1998 and has helped with certain modifications to Collins. In 1972 he was granted a personal chair and since retirement has been invited to continue as a Professorial Fellow. He was awarded a medal in the Order of Australia in 1996 for contributions to road and yacht safety. He was awarded the AGM Michell medal in 2001 by the College of Mechanical Engineers and is a Fellow of the Australian Academy of Technological Science and Engineering. As a yacht designer he has had over 100 yachts built to his designs, including a high-speed catamaran for the world sailing speed record and ocean racing yachts. Some of these have won against world-class competition – the Sydney-to-Hobart race in 1983 and second places in 1968, 2002 and 2003. As a sailor he has raced his own designs in 27 Sydney-toHobart races and survived the storm of 1998. In 1993 he was awarded the Commodore’s medal of the Cruising Yacht Club of Australia for outstanding seamanship after his crew had rescued eight survivors from a sunken yacht at night in a strong gale.

Artificial Intelligence Programming Assignment :: Essays Papers

Artificial Intelligence Programming Assignment Problem Statements Eight-Queens Puzzle Is it possible to place eight Queens on a chessboard, so that none of the Queens occupy the same row, column, or diagonal? Binary Search Depth-First & Breadth-First Search Newton’s Method Take a number whose square root is to be calculated, any positive number. Take a guess at the number’s square root. Calculate the square root by improving on the current guess as indicated: Next guess = (number/ current guess + current guess)/ 2 Repeat this process until the difference between the next guess and the current is within the accepted level of accuracy. The better your guess, the fewer the number of iterations needed to get the square root. A good first guess is typically half the number whose square root is to be calculated. The process is ten repeated until the desired accuracy is achieved. Newton-Raphson Method Determine a root of the equation f(x) = x^3-x^2-9x+9 = 0 using the Newton-Raphson method if the initial guess is x1 = 1.5. Gauss-Siedel Method Solve the following set of linear simultaneous equations using the Gauss-Seidel method: 10x1 + 2x2 + 3x3 = 11 X1 + 5x2 + 2x3 = 20 3x1 + 2x2 + 6x3 = -12 Theoretical Solutions Eight-Queens Puzzle 1. Pick a position for the Queen 2. If legal, go to next row. 3. If illegal, pick the next position. 4. If no legal position is found, back up to one row. If legal positions are found for all eight rows, the problem is solved. Binary Search †¢ Search the current node value to see if it equals the search value. †¢ If the search value is smaller than the current value, make the current node the left child node. †¢ Make the current node the right child node. Depth-First & Breadth-First Search Depth-First Search: †¢ Searches as far down the left side of the binary tree. †¢ When it encounters, NULL, the search switches to the bottom-most right child and resumes. Breadth-First Search: †¢ Remove a node from the queue. This becomes the current node. †¢ Place all child nodes of the current node onto the queue. Newton’s Method †¢ Get a positive number whose square root is to be calculated from the user. †¢ Get the desired precision. †¢ While more numbers remain, calculate firs guess, x0. †¢ Repeat Xn = 0.5 * (X (n-1) + Number/ X (n-1)) Until abs (Xn - X (n – 1)) *= Desired precision Get a positive number whose square root is to be calculated from the user. Get the desired precision. End while Newton-Raphson Method 1. Set number of iterations num_iter to zero.

What methods does Austen use to tell the story in Pride and Prejudice Chapter 43?

Jane Austen has started off chapter 43 using a telling method in a third person narrative to tell us the eyewitness of the story of what we as readers want to know, this is effective as Austen is describing the setting and the even that will take place later on in the chapter. The point of view in this chapter of Pride and Prejudice is omniscient; as story is told through Elizabeth, but as a third person. This chapter is a turning point of this novel as Elizabeth is starting to changer her views on Mr. Darcy as Austen says â€Å"there was certainly at this moment, in Elizabeth's mind, a more gentle sensation towards the original†. Elizabeth starts to change her feelings she had for Mr. Darcy after hearing Mrs. Reynolds praise so much about him describing him as â€Å"sweet tempered† and â€Å"generous hearted†. Furthermore, focalization is used throughout this chapter continuously as Elizabeth's point of view is being narrated; although Austen speaks she narrates it through Elizabeth's speeches and views. In this chapter when Elizabeth takes a trip to Pemberley, Austen tells the reader that her â€Å"spirits go into a high flutter† as soon as she sees a sight of it, this show the reader she had a little bit of excitement in her that she will be seeing Mr. Darcy. As in the previous chapter when Elizabeth turns down his proposal she now suddenly has a thought that â€Å"to be the mistress of Pemberley might be something† this shows the readers that Elizabeth point of view towards Darcy is starting to change slowly where as in the previous chapters she would never have thought of this idea, Austen showed the readers using a foreshadowing method in the previous chapters that Elizabeth later on in the novel at some point will change her feelings toward Darcy even if she doesn't completely like him. As Elizabeth and her aunt, uncle are driving into the Pemberley Park, Austen uses a lot of descriptive language to engage the readers by capturing their attention. Even though she had a lot in her mind, she still admired every second she saw while driving into the park as Austen using the telling method informs the readers that â€Å"Elizabeth was delighted. She had never seen a place for which nature had done more, or when natural beauty had been so little counteracted by an awkward taste.† the nature of it was complemented by art such as by the artificial landscaping. Here Jane Austen expresses the beauty of the grounds as â€Å"a beautiful wood† and â€Å"a large handsome stone building†. This automatically has an effect on Elizabeth's views. Although she was excited she still did not look forward to meeting its owner as Austen using a showing method informs the readers about Elizabeth's feelings. In this chapter Austen also uses contrast of the two parks that Elizabeth saw such as Lady Catherine's at Rosings which might be compared with Mr. Darcy as Austen says through Elizabeth's point of view â€Å"The rooms were lofty and handsome† and â€Å"Elizabeth saw, with admiration of his taste that is was neither gaudy nor uselessly fine, with less of splendour, and more real elegance, than the furniture of Rosings† contrast is effective in this chapter show the Austen describing the difference between two entities. The house and grounds of Darcy reflect his character and tastes. For a moment Elizabeth realises that she has some kind of regret that she rejected Darcy's proposal as she says â€Å"This was a lucky recollection – it had saved her from something like regret†. Austen has yet presented the readers with another evidence that Elizabeth's views were changing toward Darcy. As Mrs. Reynolds describes Darcy's character to Elizabeth, she realises that is completely different from what she had seen as Mrs. Reynolds says â€Å"I do not know is good enough for his good temper†. As soon as Mrs. Reynolds asks Elizabeth whether she thinks Darcy is handsome, she blushes and says â€Å"Yes, very handsome† Austen through showing method shows the readers that Elizabeth was blushing as soon as Mrs. Reynolds asked her a question about Darcy as she says â€Å"Elizabeth coloured† through third person narrative, this is effective because the readers get to see the overview of Elizabeth's feeling changing slowly. When Mrs. Reynolds describe Darcy as â€Å"sweet tempered† Elizabeth with shock questions herself saying â€Å"Can this be Mr. Darcy?† as se couldn't believe her ears, her firmest opinion of Mr. Darcy was quite the opposite one, and now she is only hearing good about him. Elizabeth becomes quite eager to hear more of Mr. Darcy as Austen informs the readers that her feelings are changing. Austen has also used different choice of punctuation as Elizabeth speech uses exclamation mark to show her strong feelings. Elizabeth now has realized that Mr. Darcy used to smile at her when their eyes met as Austen's informs the readers â€Å"as she remembered to have sometime seen, when he looked at her†, she used dramatic irony in Elizabeth's speech in chapter 6 when Elizabeth and charlotte talk about Jane as Elizabeth tells Charlotte that Mr. Bingley is simpleton not to discover Jane's affection where as she was almost describing her situation because she also missed out on Darcy's affection as she now realizes it. Elizabeth also questions herself making herself believe that â€Å"what praise is more valuable than a praise of an intelligent servant?† Austen tells the readers that her views on Darcy are being changed a lot as she is now starting to question herself of why she had so much prejudice toward him through a showing method, also the use of exclamation mark showing her strong feelings. As soon as Darcy comes and talks to Elizabeth, Austen through telling method informs the readers that she was starting to show affection toward him by being shy and blushing which is a symbol of love. She also started to care about what might have thought about her when they were talking whereas in the previous chapter she did not careless about his feelings as Austen says â€Å"whether he had felt more pain or pleasure seeing her†. She is very surprised to see that Darcy changed his manners for her sake as she tells Mrs. Gardiner â€Å"it cannot be for me, it cannot be for my sake that his manners are thus softened† Austen has used italic on personal pronouns to emphasize Elizabeth's feelings and views as she is very surprised to see Darcy changing his character for a lady who didn't tempt him when he saw her. When Darcy asks Elizabeth's permission to be introduced to his sister which is Miss Darcy, she feels honored as Austen through telling method informs the readers about this as she says â€Å"but she was flattered and pleased† she was so happy to hear such a complement from Mr. Darcy as it was of the highest kind. Elizabeth feels guilty for having prejudice towards Mr. Darcy however she doesn't say anything as she remains stays quite about that subject. Darcy has won her affection and Elizabeth has dropped her wrong views that she had also about him as Darcy spoke to her with â€Å"perfect civility† and with â€Å"civil enquiries†, she feels astonished by Darcy's altered behaviour just for her. Pride and Prejudice is a novel in which Jane Austen has used several techniques concerning the sense of place to create a fine novel of mannerisms, misjudgments, and mayhem. Austen's choice of word moved Elizabeth's feelings towards Darcy in a way that whatever he did and said to her she admired it. Through a dialogue of Mrs. Reynolds and Elizabeth's aunt and uncle, Austen introduces Darcy's real characteristics to the readers. There is also use of archaic language in this chapter for example when Austen uses the term â€Å"adieu† and â€Å"vexation† to show the readers the time period it was set in as well as wanting us to see the aspect of life.

Funny in Farsi Immigration Essay - 1202 Words

Nicola Rahman English-Ms.Esmail America has often been called â€Å"The Land of the Free†, where opportunities are like the bounteous fish caught at sea; the catch may be large or small, may come sooner or later. Just as the Gold Rush prompted for many miners to come about, the promising opportunities have prompted for immigrants to pour into in America. Although this chance for a new beginning has vastly beckoned immigrants, there are sacrifices immigrants must make along with newfound chances. Succumbing to social alienation is one of the sacrifices that immigrants must make. In the memoir,†¦show more content†¦Nobody wanted to hire an Iranian.†(Dumas 117.) Coinciding with the urgency of unemployment due to societal prejudices, Djuro J. Vrga’s views on the matter are quite blunt, â€Å" An immigrant must make two kinds of adjustments: (1) to his own ethnic group, and (2) to the larger society.† (Vrga 239.) Without restriction to the Iranian Revolution, Dumas’ experience and Vrga’s analogy reveal a now unearthed concept that social alienation is composed of both a minority and a versing majority. All throughout her life, Firoozeh Dumas was forced to contend to a traditional upbringing contrary to the contemporary surroundings she lived in. These two opposing factors were the necessary ingredients creating the recipe for social alienation, whereas if Dumas were not Iranian and born purely American there would be a missing ingredient. Even in marital matters, Dumas faced the same kind of discouraging social issues, â€Å" Francois and I had agreed that we would be married both in the Catholic Church and in a traditional Persian ceremony. The tough part was finding a Catholic priest who would be willing to officiate at a mixed marriage.† (Dumas 145-146.) The interracial circumstances binding the wedding like a serpent does its prey, Firoozeh Dumas consistently meets with American shortcomings. In 1977, Washington, D.C., Iranians were invited to welcome the Shah, or Iranian leader, who was scheduled to meet Jimmy Carter, a newlyShow MoreRelated Marjane Satrapis Persepolis3668 Words   |  15 Pagesinvaded Iran in hopes of capturing the oil- rich country amidst the Revolutionary turmoil, further contributing to Iranian emigration to European countries. The Iran Iraq War continued until 1988. The mass exodus resulted in the forced dispersal, immigration, displacement and establishment of reconfigured transnational communities, now known as the Iranian diaspora (Agnew 19).Such abrupt uprooting of a citizens identity and physical connection to their homeland leads to a conflicting sense of