Dairesel Kesitli Bir Silindir Etrafındaki Akış Gürültüsünün Sayısal Ve Analitik Olarak İncelenmesi

Konferans Bildirisi-- İstanbul Teknik Üniversitesi, Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2017Conference Paper -- İstanbul Technical University, Theoretical and Applied Mechanical Turkish National Committee, 2017Akış kaynaklı gürültünün hesaplanması ve tahmini, uzun yıllardır akustik alanında araştırma yapanların hedefi olmuştur. Son yıllarda, su altı cisimleri etrafındaki akış gürültüsünün belirlenmesi, denizcilik endüstrisinde ticari ve ekolojik olarak önemli bir konu haline gelmiştir. Bu çalışmada dairesel kesitli bir silindir etrafındaki akış gürültüsü, sayısal ve analitik metotlar kullanılarak incelenmiştir. Akustik analizler, farklı Reynolds sayılarında dairesel silindirin hidroakustik performansını değerlendirmek amacıyla gerçekleştirilmiştir. Silindir etrafındaki akış karakteristikleri, hesaplamalı akışkanlar dinamiği (CFD) yardımıyla belirlenmiştir. Uzak alan akış gürültüsünün sayısal olarak hesaplanmasında ise Ffowcs Williams & Hawkings (FWH) metodu kullanılmıştır. Bunun yanında, Proudman akustik analojisine dayanan k-ε gürültü metodu kullanılarak, toplam akustik güç ve akış gürültüsü seviyeleri analitik olarak hesaplanmıştır. Farklı metotlar kullanılarak elde edilen sonuçlar, literatürde yer alan analiz sonuçları ile karşılaştırılmıştır. Ayrıca, alıcı nokta uzaklığının ve akışkan hızının akış gürültüsü üzerindeki etkileri incelenmiştir.The prediction of the flow-induced noise has been the target of those who have been researching in the field of acoustics for many years. Recently, flow noise around submerged bodies used in marine industries has become commercially and ecologically an important issue. In this paper, the flow-induced noise around the circular cylinder is investigated by using numerical and analytical methods. The acoustic analysis is performed to examine the hydro-acoustic performance of the circular cylinder at various Reynolds numbers. Flow characteristics around the circular cylinder are calculated by employing Computational Fluid Dynamics using finite volume method. The flow-induced noise has been calculated by solving Ffowcs Williams and Hawkings equations. A k- Ԑ sound model based on Proudman analogy is also employed to approximate the total sound power and flow noise generated by turbulent flow past over the circular cylinder, analytically. The results obtained using the FW-H and the k-Ԑ sound methods are presented and compared with experimental and numerical data in the literature. In addition, the effects of receiver distance and flow velocity on flow-induced noise are examined

A Rare Cardiac Anomaly in Absent Pulmonary Valve Syndrome with Tetralogy of Fallot

Heart failure and cardiomegaly are observed in patients with absent pulmonary valve syndrome with tetralogy of Fallot (TOF), unlike in those with TOF alone. Additional cardiac anomalies can also be seen in these patients, although not frequently. In our case, we found that the right and left pulmonary arteries were disconnected (the main pulmonary artery continued only with the right pulmonary artery and the left pulmonary artery originating from patent ductus arteriosus). In this paper, we wanted to remember other cardiac anomalies associated with absent pulmonary valve syndrome with tetralogy of Fallot

Uzbek and Turkmen narratives which came into exist Ali Shir Nawai

"Ali Şir Nevâyî Etrafında Teşekkül Etmiş Özbek ve Türkmen Rivayetleri" isimli bu çalışmada Türk edebiyatının en müstesna şahsiyetlerinden biri olan Ali Şir Nevâyî etrafında teşekkül etmiş rivayetler değişik yönlerden incelemeye tabi tutulmuştur. Tez, Giriş'ten sonra beş bölümden oluşmaktadır. Birinci bölümde Nevâyî' nin tarihî kaynaklara göre hayatı, edebiyatımızdaki yeri ve eserlerine yer verilmiştir. İkinci bölümde söz konusu anlatmalar, anlatım tüm bakımından efsanelerin paralel bir kolu olduğunu düşündüğümüz rivayetler grubuna girdiği için öncelikle efsane-rivayet kavramları üzerinde durulmuştur. Üçüncü bölümde Nevâyî'nin rivayetlere göre hayatı ve kişisel özelliklerine yer verilerek Nevâyî'ye bağlı olarak anlatılan rivayetlerin konularına göre tasnifi de yapılmıştır. Dördüncü Bölüm, rivayetlerin anlatım türü bakımından değerlendirilmesi ve rivayetlerde tespit ettiğimiz fıkra ve masal özelliği gösteren anlatmaların incelenmesinden oluşmaktadır. Beşinci Bölüm söz konusu incelememize kaynak teşkil eden Özbek ve Türkmen sahalarında anlatılan rivayetleri içermektedir. Sonuç bölümünde çalışmanın vardığı neticeler açıklanmıştır. Kaynakça kısmında ise çalışma esnasında faydalanılan eserlerin künyeleri verilmiştir.In this study, named "Uzbek and Turkmen Narratives Which Came Into Exist AH Shir Nawai", folk tellings, came into existence around AH Shir Nawai who was one of the most distinguished characters of Turkish literature, was examined in different ways. The thesis includes five chapter, except introduction. In the first chapter Nawai's life was examined according to historical sources, his place in our literature and his works. In the second chapter, firstly it was dwelled on the legend-narrative concepts; because these tellings are placed narratives category that are branch of legend according to manner of telling. In the third chapter Nawai's life and his character are examined in the view of narratives; also, the narratives were classified according to their subjects. The fourth chapter exists of the evaluation of narratives in the view of manner of telling, jokes, found of narrations and narrations having character of fairy tale. The fifth chapter includes the narratives, which were told in Uzbek and Turkmen domains and sources of our research. i In the conclusion results, obtained from the study, were explained

The investigation of the transliteration of Uzbek folk tales

Bu tezde otuz yedi Özbek masalı incelenerek, masallardaki tipler tek tek tespit edilmiştir. Tezin ana bölümleri; Önsöz, İşaretler, Giriş, Kahramanlar, Metin ve Sözlük’ten oluşmaktadır. Kahramanlar bölümü; İnsanlar, Hayvanlar ve Olağanüstü Varlıklar adı altında üçe ayrılmıştır. “Bir Bar Eken” adlı Özbek Türkçesi ile yazılmış bu masallar, öncelikle Türkiye Türkçesi’ne aktarılmıştır. Bu masallar konuları itibariyle; “Kahramanlık” “Dostluk” ve Maceralar” olmak üzere üç grupta toplanmıştır.By inspecting thirty seven Uzbek tales characters in tales were determined one by one. main parts of the thesis consist of preface, signs, introduction, Heros, text and dictionary.Part of heroes was classified under the title; “Humanbeings”, “Animals”, and “Extraordinary creatures”.These tales written by Uzbek Turkish named “Bir Bar Eken”, first of all, were translated into Türkiye Turkish. These tales are grouped into depending on their topics as followings; “heroism”, “friendship” and “ adventures

Thermo-environmental analysis and performance optimisation of transcritical organic Rankine cycle system for waste heat recovery of a marine diesel engine

Ergin, Selma/0000-0001-8343-2455WOS: 000571296000001Energy efficient and environmentally friendly shipping have been primary concerns for the maritime industry. One of the alternatives to overcome these issues onboard is organic Rankine cycle (ORC) waste heat recovery system (WHRS). In this study, a transcritical ORC WHRS for a marine diesel engine is investigated at different engine operating loads by thermodynamic and environmental analysis. The engine exhaust gas is used as the waste heat source and R152a is selected as the working fluid. The energetic, exergetic and environmental parameters are analysed and the performance optimisation is conducted by using genetic algorithm. The results indicate that by employing the ORC system onboard, it is possible to increase the overall thermal efficiency of the ship power generation system by more than 2.5% and the system can save up to 678.1 tonnes CO(2)per year when the system is operated at the optimal conditions

An investigation of exhaust smoke dispersion for a generic frigate by numerical analysis and experiment

The effects of efflux velocity, operational conditions, stack geometry, and buoyancy on the exhaust dispersion for a generic frigate are investigated numerically. The conservation of energy, momentum, mass, species, and turbulence equations have been solved using the finite volume method. It is found that the exhaust smoke dispersion is affected by the efflux velocity, operational conditions, buoyancy, and turbulence, as well as the geometry of the stack. The momentum of the exhaust gases and the plume height increase as the velocity ratio increases. The results for the slow ahead operation condition show that the buoyancy effect is the strongest, and the plume height is minimum for this case. The exhaust temperatures and velocity values for the full ahead operation are found to be the highest. However, the plume height for this case is not maximum. This may be attributed to the high turbulence levels for this case. It is found that the effect of stack geometry on the exhaust smoke dispersion is not significant for the geometries considered in the study. The computations are validated with the flow visualization tests carried out in a wind tunnel. The agreement between the numerical and experimental results is found to be good. </jats:p