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Günümüzde birçok donanma denizaltılara sahip durumdadır ve birçoğu denizaltılarını donanmaların bel kemiği olarak ifade etmektedir. Tarihte birincil harekât görevi deniz ticaret yollarını kesmek/kontrol etmek olan dizel elektrikli denizaltıların günümüzde en önemli görevleri fark edilmeden bilgi toplamak ve gerektiğinde su altı, su üstü, kara ve hava hedeflerine sürpriz harekât gerçekleştirebilmektir. Denizaltılar su üstüne çıktıklarında ve hatta gövdeleri su üstüne çıkmadan sadece şnorkel seyri yapmak için periskop derinliğine geldiklerinde dahi günümüzün yüksek teknolojik radar sistemleri sayesinde fark edilebilmekte ve görünmezliklerini yitirmektedirler. Denizaltıların seyirleri esnasında bataryalarını şarj ettikleri sürenin, denizaltıların su altında geçirdikleri süreye oranı, şnorkel seyir süresi oranı (indiscretion rate) olarak isimlendirilmektedir. Bu oranı azaltmak, denizaltıların görünmezliğinin bir ölçüsü olarak nitelendirilmektedir. Yeni tasarımlar ve teknolojiler geliştirilirken bu oranı aşağı çekmek ana tasarım hedefi olarak ele alınmaktadır. Denizaltıların su altı seyir sığalarını önemli ölçüde artıran havadan bağımsız sevk sistemleri modern denizaltıların şnorkel seyir süresi oranını aşağı çekmiş ve bu sistemlerle donatılmış günümüz denizaltısının harekât sahası, kahverengi sulardan mavi sulara kaymaktadır. Şnorkel seyir süresi oranına diğer bir önemli etken ise denizaltının hidrodinamik formu ve sevk verimliliğidir. Daha verimli bir forma sahip olan denizaltı su altında aynı sürat ve aynı enerji kapasitesi ile daha uzun süre seyir yapabilecek ve daha düşük bir şnorkel seyir süresi oranına sahip olacaktır. Günümüzde hesaplamalı akışkanlar dinamiği tasarımcılar tarafından etkin bir araç olarak kullanılmakta ve denizaltıyı istenilen servis süratlerinde daha verimli sevk edebilecek hidrodinamik formların ve bu formları itecek pervanelerin gerek yüksek verimle gerekse düşük akustik ize sahip olarak tasarlanabilmesine olanak tanımaktadır. Bu çalışmada, açık literatürde yapılan çalışmalarda son yıllarda sıklıkla tercih edilen Joubert BB2 denizaltı formunun direnci hesaplamalı akışkanlar dinamiği yöntemleri ile hesaplanmış ve denizaltının sevkinde kullanılan pervanenin geminin servis hızında gemiyi itmek için gereken devir sayısı bilgilerine ulaşılmıştır. Sevk noktasının tayini ile denizaltı formuna has Taylor iz katsayısı, itme azalması, tekne verimi, bağıl dönme verimi ve bunlara bağlı sevk verimi hesap edilmiştir.
Today, many ships have submarines, and many of them express their submarines as the back bone of the ships. The primary task in history is to collect information without notice of the most important tasks of today’s diesel-electric submarines, which are to interrupt/control the maritime trade routes, and to be able to carry out surprising movements to the ground, underwater, ground and air targets when necessary. Even when the submarines go out on the water and even when their bodies come to the periscope depths to just make a snorkeling journey without going on the water, they can be noticed and lost their invisibility thanks to today’s high-tech radar systems. The percentage of the time the submarines charge their batteries during their trips, the percentage of the time the submarines spend under water, is called the indiscretion rate (indiscretion rate). Reducing this ratio is considered a measure of the invisibility of the submarines. As new designs and technologies are being developed, the main design goal is to draw this ratio down. The air-independent shipping systems that significantly increase the submarine submarine shipping stairs have reduced the rate of the modern submarine snorkel shipping time, and the operating area of today's submarine equipped with these systems is shifting from brown waters to blue waters. Another important factor in the shipping time ratio is the hydrodynamic form and shipping efficiency of the submarine. The more efficient form of the submarine will be able to travel longer under the water at the same speed and energy capacity, and will have a lower snorkeling time rate. Currently calculated fluid dynamics are used by designers as an effective tool and enables the hydrodynamic forms that can deliver the submarine more efficiently at the desired service speed and the pervans that push these forms to be designed with high efficiency or low acoustic speed. In this study, studies in open literature often preferred in recent years Joubert BB2 submarine form resistance calculated fluid dynamics methods were calculated and the number of turns needed to push the ship at the service speed of the pervanin used in the submarine shipping. With the designation of the shipping point and the form of the submarine, the Taylor trace ratio, the reduction of the push, the boat yield, the yield of connectivity and the yield of shipping associated with them have been calculated.
Nowadays many Navies have submarines and refer them as the backbone of their Navies. The most important task of diesel-electric submarines, whose primary operational task in history was to intercept / control maritime trade routes, is to collect information without being noticed and to perform surprise operations against underwater, land and air targets when necessary. Submarines can be noticed and lose their invisibility thanks to today's high-tech radar systems when they come to the surface of the water and even when they reach periscope depth to go snorkeling without their hulls rising above the water. The ratio of the time submarines charges their batteries during their cruise to the time the submarines spend under water is called indiscretion rate. Reducing this rate is considered as a measure of the invisibility of submarines. While developing new designs and technologies, reducing this rate is considered as the main design goal. Air-independent propulsion systems, which significantly increase the underwater sailing range of submarines, have lowered the rate of snorkeling time of modern submarines, and the operation area of today's submarine equipped with these systems shifts from brown waters to blue waters. Another important factor in the rate of snorkeling cruising time is the hydrodynamic form and the propulsive efficiency of the submarine. The submarine, which has a more efficient form, will be able to cruise for a longer time with the same speed and same energy capacity underwater and will have a lower indiscretion rate. Nowadays, computational fluid dynamics is used by designers as an effective tool and enables the design of hydrodynamic forms that can drive the submarine more efficiently at desired service speeds and the propellers that will push these forms with both high efficiency and low acoustic trace. In this study, the self-propulsion characteristics of the Joubert BB2 submarine form, which has been frequently preferred in recent years in the studies conducted in the open literature, was calculated with computational fluid dynamics methods and the speed of the propeller used in the propulsion of the submarine was obtained to propel the ship at the service speed of the submarine. With the determination of the self-propulsion point, the Taylor wake fraction, thrust deduction, hull efficiency, relative rotative efficiency and propulsive efficiency were calculated and compared with open literature.
Field : Mühendislik
Journal Type : Uluslararası
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