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Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2009, Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2009, Bu çalışmada tsunami tipli uzun boylu dalgaların düşey yüzlü kıyı yapısı olan kesonlar üzerindeki basınç etkisinin deneysel olarak incelenmesi ve kesonların Marmara denizinde tsunamilere karşı nasıl davrandığı üzerinde çalışılmıştır. İ.T.Ü. Hidrolik Laboratuarında tsunami dalgasının keson yapı üzerindeki basınç etkisini belirlemek için tsunami kanalında bir deney düzeneği kuruldu. Farklı su derinliklerinde korumalı ve korumasız olarak yapılan deneylerde su derinliği az olan yapılarda daha büyük basınçlar oluşmaktadır. Tsunami dalgalarına karşı koyabilecek kıyı yapıları tasarlarken su seviyesi ve üzerindeki yüzeylerin doğru projelendirilmesi çok önem arzetmektedir. Marmara denizinde muhtemel bir tsunami durumunda keson yapıların kullanılmasının herhangi bir mahzuru olmadığı belirlenmiştir., The purpose of this study is to determine the effects of tsunami waves generated by earthquakes on the vertical coastal structures on Marmara Sea Coast. A tsunami is a series of very long wavelength waves caused by sudden displacement of the sea floor as a result of any tectonic activity. The effects of tsunami waves caused by earthquakes on caisson structures in the Marmara Region are investigated, under which tsunami risk will be determined and rehabilitated. In addition, the protection systems for coastal structures subjected to the possible effects of tsunami waves will be developed. At the end of the study, coastal structures building codes against tsunamis will specially be developed and prepared., Yüksek Lisans, M.Sc.

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2009, Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2009, Tsunami (soliter) tipli dalgaların normal keson ve delikli keson dalgakıranları nasıl etkilediğini öğrenmek amacıyla İTÜ Hidrolik Anabilim Dalı laboratuarındaki 120*2*2 metre boyutlarında bulunan kanalda çeşitli deneyler yapılmıştır. Önce özel sistem pistonla oluşturulmuş dalgalar normal keson dalgakıran üzerine gönderilmiştir. Bu deneylerde normal keson üzerinde oluşan basınç ve tırmanma ölçülmüştür. Daha sonra aynı şartlarda oluşturulmuş dalgalar delikli keson dalgakıran üzerine gönderilmiş ve aynı şekilde basınç ve tırmanma ölçülmüştür. En nihayetinde veriler karşılaştırılarak herhangi bir tsunami dalgasına karşı normal ve delikli keson dalgakıranların hangisinin daha üstün olduğu kararlaştırılmıştır. Delikli keson dalgakıranların tırmanmayı azalttığı, delikli sistemde ve keson sistemde maksimum basıncın su seviyesinde oluştuğu gözlemlenmiştir. Ayrıca delikli sistemin dalgayı daha fazla yansıttığı gözlemlenmiştir. Bunlarla ilgili regresyon analiziyle formüller elde edilmiştir. Sonuç olarak tsunami dalgalarına karşın delikli keson dalgakıranların normal keson dalgakıranlara göre daha üstün olduğu gözlemlenmiştir. Bunun yanında delikli sistem üzerinde yapılan hücre mesafesi ayarlamasında, hücre mesafesinin tırmanma ve basınç değerlerini azaltıp azaltmadığını anlamak amacıyla hücre mesafesi değiştirilerek aynı dalgalar tekrar gönderilmiş ve elde edilen veriler birbiriyle karşılaştırılmıştır. Bunun sonucunda hücre mesafesinin artmasının keson üzerindeki basınç ve tırmanmayı azalttığı gözlemlenmiştir. Sonuç olarak keson dalgakıranların derin kıyılarda dökmetaş dalgakıranlara karşı daha avantajlı olduğu zaten bilinmekteydi. Keson dalgakıranların bir türü olan delikli keson dalgakıranların normal keson dalgakıranlara oranla basınç ve tırmanmayı azaltmada daha avantajlı olduğuda bu tezle ortaya çıkmış oldu., Some experiments were made to learn and to compare the affects of tsunami waves on caisson and perforated breakwater in a channel which`s length is 120 m, largeness is 2 m and depth is 2 m in ITU Hydraulics Division Laboratory. Firstly, run up and pressure values were measured on caisson breakwater. And later, run up and pressure were measured on perforated breakwater, too. And then, the advantages of caisson breakwater and perforated breakwater were compared against tsunami waves. Perforated breakwater decreases run up, maximum pressure was measured on water level on both of caisson breakwater and perforated breakwater. In addition, perforated breakwater reflects wave more than caisson breakwater does. Some formulas have been found by using regression analysis. As a result, perforated breakwaters are more advantageous than caisson breakwater under tsunami waves. Beside this, to understand the affect of chamber length on decreasing the pressure and run up, the chamber length was changed and the same waves were created on perforated breakwater. And after the comparison of results, it is understood that the more chamber length is the more decrease on pressure and run up. Finally, it is known that caisson breakwaters are more advantageous than the rubble mount breakwaters on deep water. Perforated breakwaters which are a kind of caisson breakwaters are more advantageous than caisson breakwaters on decreasing pressure and run up,too., Yüksek Lisans, M.Sc.

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2001, Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2001, Nehirlerdeki sediment taşınımı sonucu yapılan tesislerin ekonomik ömrü azaldığı gibi, bu durum aynı zamanda tarımsal ekonomimizin en önemli üretim kaynaklarından birisi olan toprağın üst tabakasının yok olmasına da neden olmaktadır. Bunun doğal sonucudur ki çıplaklaşan ve çoraklaşan ülke topraklarında erozyon ve sedimentasyon olayları ile birlikte işlenebilir tarım arazilerinin yok olması ve çevre kirliliği sorunları da gündeme gelmiş bulunmaktadır. Bu çalışmada rezervuar sedimantasyonu hesap analitik metodaları olan “minimum akış gücü metodu” ve “alan eksiltme metodları” yanında HEC-6 sayısal modeli incelenmiştir. Bir boyutlu, hareketli-sınırlı açık kanal akımı sayısal modeli olan HEC-6, pek de uzun olmayan bir sürede akarsu profillerinde oyulma ve/veya birikme sonucu meydana gelen değişiklikleri simule etmek ve önceden tahmin etmek amacıyla tasarımlanmıştır. Model performansı, mutlak yanılma paylarının ortalaması alınarak nicelendirilebilir. Kuşkusuz, en düşük ortalama yanılma değeri, en iyi performansı gösterir. Performans kalitesi, incelemeye-özgü özellikle tanımlanır ve büyük bir olasılıkla her çalışmaya göre değişecektir. Modelin performansının yeterli olduğunu ya da başka ayarlamalar gerektiğini ancak iyi bir mühendislik kararı belirleyecektir., Sediment transportation in streams results both in reduced economical service life of a facility which is in operation and destruction of topsoil which is one of the most important production resources for national agricultural economy. As a natural outcome of erosion and sedimentation phenomena, lands have become barren and arid, ultimately resulting in the limited arable area and environmental pollution problems. This paper includes a study on HEC-6 numerical model further to “minimum flow tractive force” and “area reduction” analytical methods used for reservoir sedimentation calculations. HEC-6, being a single dimension numerical model for mobile-boundary open channel flow, is designed to simulate and predict changes in stream cross sections over a reasonably long period of time due to scouring and/or deposition. Model performencemay be quantified by computing the mean of the absolute values of error. Of course,the lower the mean value of error, the better the performance. Performance quality is defined by study specific characteristics and will differ from study to study. Good engineering judgment should be used to determine when the model’s performance is satisfactory or requires additional adjustment., Yüksek Lisans, M.Sc.

ÇÖZÜLEBİLEN MADDELERİN DALGA ETKİSİYLE BOYUNA TÜRBÜLANS DİFÜZYONU VE DİSPERSİYONU ÖZET Doğal güzelliğe ve kaynaklara sahip olan denizlerin önemi günümüzde daha da iyi anlaşılmaktadır. Son yıllarda denizlerin bilinçsizce kirletilmesiyle bu imkanlar yok olmaya yüz tutmuştur. Kısıtlı olan doğal kaynakların yalnız bugünler için olmadığı da herkesçe bilinmektedir. Bu çalışmanın amacı denizlere yapılan deşarjların oluşturduğu kirliliklerin dalgalarla nasıl iletildiğinin incelenmesidir. Deniz şartlarının önemli bir elemanı olan dalgaların atık tarlasının dispersiyonunda önemli bir rolü vardır. Çalışmada atık tarlasındaki atıkların dalga etkisi altında nasıl bir mekanizmayla taşındığı belirlenmiştir. Çalışma beş ana bölümden oluşmaktadır. Birinci bölümde dalgaların dispersiyon üzerindeki etkisiyle ilgili çalışmalar kritik edilmiştir. Yapılan literatür çalışması sonunda bu konu üzerinde çok az sayıda çalışma olduğu görülmüştür. İkinci ve üçüncü bölümde dalga hareketi mekaniği ve dalga kırılması olayı hakkında bilgi verilmiştir. Dalgaların özellikleri, tanımlar ve dalgaların hareketine ait bir takım teoriler bu bölümde sunulmuştur. Dördüncü bölümde ise dalgalarla madde iletimi üzerinde bir dizi deneysel çalışma yapılmıştır. Durgun su ortamındaki madde iletimi ile dalgalı su ortamındaki madde iletimi kıyaslanmıştır. Dalgalı su ortamında maddenin daha hızlı iletileceği ve yüksek derecede bir seyrelme olacağı sonucuna varılmıştır. Yine aynı bölümde, dalga etkisiyle nasıl bir taşınım mekanizması oluştuğu yapılan testler sonucunda belirlenmiştir. Tatbikatta da en uygun deşarj derinliğinin tespiti son derece önemlidir. IXAtık maddenin emniyetli bir derinlikte kalacağı ve yeterli bir seyrelme yapacağı deşarj derinliği araştırılmıştır. Yapılan testler sonucunda en uygun deşarj derinliğinin, su derinliğinin %69'u oranında olduğu bulunmuştur. Dalga hareketinin artmasıyla atık tarlasının dağılımı gözlenmiştir. Dalga dikliğinin artırılması sonucunda iletimin hızlandığı gözlenmiştir. Beşinci bölümde ise deneysel çalışmalarda bulunan sonuçların bir değerlendirilmesi yapılmıştır. Bu sonuçların geçmişte muhtelif araştırmacılar tarafından ortaya konulan bazı sonuçlar ile uyum içinde olduğu görülmüştür. TURBULENT DIFFUSION AND DISPERSION OF SOLUBLE MATTERS BY MEANS OF WAVES SUMMARY The importance of the natural beauty and the resources of the seas are most understood these days. In recent years unconscious contamination of the seas has resulted in the vanishment of these resources. It is a well-known fact that these limited natural resources are not only confined to present days. The aim of this study is to examine the mode dispersion of the contaminants formed as a result of discharges to the sea. Waves; the important elements of sea condition, have a crucial influence in the dispersion of the wastefields. In this study the transport mechanism of the waste matter within the wastefield, under the wave influence is determined. The study consists of five main sections. In the first section, the effects of the waves over dispersion is criticised. Literature study has revealed the fact that too little studies were conducted on this particular issue. In the second and third sections, information is given on the wave motion mechanics and wave refraction. This is the section where the characteristics of the waves, definitions and theories associated with wave motions are given. In the fourth section, consequent experimental studies are conducted on matter transport via waves. Comparisons are made with the respect to the matter transport in stagnant water versus unstilled wavy water. It has been concluded that the faster transport of matter and higher dillution occur in nonstill wavy water medium. Again in the same section with reference to the xiexperiments conducted the transfer mechanism under the influence of waves is specified. In practice, it is very important to determine the most suitable discharge depth. The depth in which the waste matter is to remain securely and the adequate discharge depth in which satisfactory dillution is to be achieved was investigated. With regards to experiments conducted; the most suitable discharge depth was found to be 69% of the water depth. It has been observed that wastefield dispersion range is related with the increasement of the wave motion. Increasing the wave steepness has resulted in an increase in the transportation of the matter. In the fifth section an assesment of the results found in the experimental studies has been done. These results were found to be in harmony with some of the results found in the past by various different investigators. XU 118

DOĞAL AKARSULARDA VE SİNÜS KANALLARDA BOYUNA DİSPERSİYON KATSAYISININ BELİRLENMESİ ÖZET Bu çalışmanın amacı, günümüzde su kaynaklarının karşı karşıya kaldığı en büyük tehlike olan kirliliğin akım doğrultusu boyunca zamanla ve konumla değişen konsantrasyon değerlerini belirlemede ve kirlilik tahminlerinde sayısal çözümün ne derece tutarlı ve gerçek davranışa uygun sonuçlar verdiğini görebilmektir. Ayrıca bir çok formül içinden özellikle doğal akarsu ve onun modeli olarak seçilen sinüs açık kanalda klasik bir ve iki boyutlu dispersiyon denklemi ile birlikte kullanılacak boyuna dispersiyon katsayısı ifadesini seçerek, seçilen boyuna dispersiyon katsayısı ile bir ve iki boyutlu çözümleri denemek, sayısal çözümleme ile elde edilen sonuçları değerlendirmek ve literatürdeki diğer ifadelerle karşılaştırmasını yapabilmektir. Atık maddenin su içinde yayılmasıni ifade eden dispersiyon mekanizması üzrinde iki bileşen etkili olmaktadır. Konveksiyon ve difüzyon. Karışım zamanı olarak tanımlanan `atık madde bulutunun akış kesitini tamamen kaplayarak kesit içinde yanal doğrultuda dağılımı uniform olana kadar geçen zaman` ve bu sürede katettiği mesafeden sonra akım doğrultusu olan boyuna doğrultudaki kirlilik konsantrasyonlarının neredeyse tek değişken durumuna geldiği Rutherford (1994) tarafından gösterilmiştir. Bu nedenle dispersiyon problemi dendiğinde genellikle boyuna dispersiyon kastedilmektedir. Bu çalışmada da dispersiyon mekanizması içinde boyuna dispersiyon konusu incelenmiştir. Boyuna doğrultudaki kirlilik konsantrasyonlarının belirlenmesi yani dispersiyon denkleminin çözümü oldukça güçtür. Atık maddenin özellikleri yanında akımın geometrik ve dinamik karakteristiklerinin bilinmesi gerekir. Bu ikisi arasındaki ilişkiler çok karmaşık olmakla birlikte henüz tam anlaşılamamıştır. Bu güçlüklere dispersiyon denkleminin kısmi diferansiyel denklem olması da eklendiğinde problemin çözümü daha da güçleşmektedir. Son yarım yüzyılda kullanılabilir su kaynaklarının kirlilik nedeniyle azalması ve varolanların korunması ile problemin yukarıda sayılan zorlukları dispersiyon-boyuna dispersiyon-konusunu popüler hale getirmiş ve bu konu bir çok araştırmacının ilgisini çekmiştir. Dispersiyon mekanizmasının her iki bileşenini de temsil eden `boyuna dispersiyon katsayısı` tanımını getiren ve Taylor ya da Fick Modeli olarak bilinen boyuna dispersiyon denklemi hemen tüm araştırmacılar tarafından kabul edilmiş temel bir denklemdir. Bu denklemin doğal akarsulardaki gerçek dispersiyon değerlerinden çok farklı sonuçlar vermesi nedeniyle bu temel denklemle kullanılabilecek boyuna dispersiyon katsayısının bulunması bir çok araştırmacının amacı haline gelmiştir. Problemin bu haliyle çözümü neredeyse olanaksız olduğundan ve pratik mühendislik amaçları için kullanılabilirliğini engellediğinden her araştırmacı kendi deneysel ortamlarında basitleştirici kabuller yaparak ya da etkisinin az olduğunu düşündükleri değişkenleri ihmal ederek birbirlerinden çok farklı sonuçlar veren boyuna dispersiyon katsayısı ifadeleri elde etmişlerdir. xııÇalışmanın 2. Bölümünde Fick Modeli üzerinde durularak Taylor denklemi elde edilmiş ve denklemin doğal akarsu ve kanallarda yaklaşık sonuçlar vermemesinin nedenleri ayrıntılarıyla tartışılmıştır. Bugüne kadar elde edilen çeşitli boyuna dispersiyon katsayısı ifadeleri topluca verilerek hangi kabul ve varsayımlarla elde edildiği ile değişik akım koşulları içinde verdikleri sonuçlar değerlendirilmiştir. Bölüm sonunda doğal akarsu ve açık kanallarda diğerlerine göre daha iyi sonuçlar verebileceği düşünülen ifadeler belirlenerek önerilmiştir. Kısmi diferansiyel bir denklem olan boyuna dispersiyon denkleminin çözümü sonlu elemanlar ya da sonlu farklar yöntemi kullanılarak yapılmaktadır. Günümüzde gelişen bilgisayar teknolojisinin sunduğu olanaklar ile yöntemin fazla matematik ve fizik bilgisi gerektirmemesi sonlu farklar yönteminin daha çok tercih edilir olmasını sağlamıştır. 3. bölümde sonlu farklar yönteminin esası, geometrik anlamı, çözüm şekilleri, stabilite kriterleri hakkında genel bilgiler verilerek Savcı'nın elde ettiği ve hesap başında l'e eşit alınmasını önerdiği; bu haliyle klasik Taylor denklemi haline gelen ifadenin sonlu farklar formuna açılmış hali ile stabilite kriterleri bir ve iki boyutlu çözüm için ayrı ayrı verilmiştir. Sayre ve Fukuoka'nın sinüs kanallar için yaptıkları deneysel çalışmaları incelenmiş ve deneyleri sonucunda elde ettikleri ve dispersiyon denklemi ile kullanılması durumunda doğal akarsu ve sinüs açık kanallarda yaklaşık sonuçlar verdiğini ifade ettikleri boyuna dispersiyon katsayısı ifadeleri ve bu ifadenin teorik altyapısı ile diğer sonuçlar değerlendirilmiştir. 4. Bölüm'de A.B.D.'deki bir doğal akarsu için Sayre'nin sinüs kanal modelinden yola çıkarak bulduğu boyuna dispersiyon katsayısı bir ve iki boyutlu boyuna dispersiyon denklemi ile sonlu farklar yönteminde açık çözüm şekli ile çözülmüştür. Çözüm sırasında gerçek ve hesaplanan dispersiyon katsayıları, sınır koşulları, ortalama kesitsel akım hızları ile çözüm adımları değiştirilerek çözüm tekrarlanmış ve bu çözümün bir hesap tablo programı olan Microsoft-Excel'deki çözüm adımları, tanımlanan formüller ayrıntılarıyla açıklanarak sonuçlar tablo ve grafikler ile verilmiştir. 5. Bölümde bir önceki bölümde yapılan hesap sonuçları bir boyutlu akımlar ve iki boyutlu akımlar için ayrı ayrı ve karşılaştırmalı olarak incelenmiştir. Bu çözümler sonucunda iki ve bir boyutlu çözümlerin özellikle başlangıç periyodu olarak tanımlanan zaman dilimi içinde çözüm için seçilen noktalarda çok farklı maksimum konsantrasyon değerleri ve oluşum zamanları verdikleri görülmüştür. 2. Bölüm'de Taylor denkleminin geçerli olduğu zaman değerleri için Fischer'in tanımladığı ifadenin iki boyutlu sayısal çözüm sonuçları ile tam olarak uyum içinde olduğu görülmüştür. İki boyutlu çözümden elde edilen sonuçların ancak bu değerden sonra bir boyutlu çözüm ile yaklaşık olarak eşitlendiği belirlenmiştir. Ayrıca sayısal çözümlerden elde edilen sonuçların gerçek davranışla uyumu tablolar ile karşılaştırılmış ve gerçek davranış ile iki boyutlu sayısal çözüm sonuçlarının tam uyum içinde olduğu anlaşılmıştır. Farklı durumlarda bir boyutlu çözümden elde edilen sonuçlar kendi aralarında da karşılaştırılmış ve tüm bu değerlendirmeler için tablo ve karşılaştırma grafikleri verilmiştir. Kısaca aşağıdakiler söylenebilir : a-)Özellikle bir boyutlu çözümlerde sistem stabil olsa da büyük adım aralıkları yerine daha sık ve küçük adımlar ile çözüm yapmak doğruluğu artırmaktadır. b-)Ortalama kesitsel hız arttığında akım için maksimum konsantrasyon azalmakta fakat çözüm için seçilen noktalardaki maksimum konsantrasyonlar artmakta ve daha önce oluşmaktadır. Başlangıç konsantrasyonuna dönüş zamanları arasındaki oranın hızlar arasındaki orana eşit olduğu gözlenmiştir. X111c-)Boyuna dispersiyon katsayısı ile sınır koşullarındaki değişimlerin sayısal çözüm sonuçlan üzerinde çok etkili olduğu gözlenmiştir. Dispersiyon katsayısındaki değişimin konumun artan değerlerinde sonuçlan daha fazla değiştirdiği çözülen örnek sonuçlanndan anlaşılmıştır. d-)Doğru boyuna dispersiyon katsayısı ve sınır koşullan belirlenmeden sayısal çözümün hiçbir anlamı yoktur. Boyuna dispersiyon katsayısı için 2. Bölümde dikkat çekilen 6 ifadenin buradaki örnektede iyi sonuçlar verdiği belirlenmiştir. Özellikle Liu ve Fischer'in yanal hız dağılım kabulü ile bulduklan ifadelerin gerçek dispersiyon katsayısına yaklaşık eşit olduğu görülmüştür. e-)İki boyutlu çözüm sonuçları bir boyutlu çözüm sonuçlarına göre uyumlu ve tutarlı sonuçlar vermektedir. Özellikle kirlilik probleminin büyük bölümü başlangıç periyodu içinde geçmekte ise İki boyutlu çözüm yapılması gerektiği bu periyottan sonra bir ve iki boyutlu çözüm sonuçlarının birbirlerine çok yakın olduğu anlaşılmıştır. XIV DETERMINATIONAL OF LONGITUDINAL DISPERSION COEFFICD2NT IN NUTURAL RIVER AND SINUOUS CHANNELS SUMMARY The purpose of this study is, to determine the changing values of concentration among the flow of pollution with time and location, which is the biggest problem today' s water sources are facing, and to see if the numerical solutions are consistent in pollution estimates and if they give results which are in accordance with the actual behaviour. Moreover, in natural river and sinuous channel which is chosen as its' model, by choosing the longitudinal dispersion coefficient to be used together with classic one and two dimensional dispersion equation among the many formulas, to try the chosen longitudinal dispersion coefficient and one and two dimensional solutions, to evaluate the results obtained by numerical solutions and to be able to compare it with other statements in literature. On dispersion mechanism, which defines the dispersion of tracer material in water, two components are effective. Diffusion and convection. It is proved by Rutherford (1994) that the pollution concentration becomes almost the only variable in longitudinal direction which becomes the flow direction after the distance it travels within the mixing time which is defined as `the time passing until the dispersion is uniform in lateral direction by fully covering tracer cloud's flow cross section`. Due to this, when dispersion problem is mentioned, usually the longitudinal dispersion is meant. In this study, longitudinal dispersion subject within dispersion mechanism is studied. The determination of pollution concentration in longitudinal direction, which means the solving of dispersion equation is very hard. Among the specifications of the waste material, the geometric and dynamic characteristics of the flow should also be known. Eventhough the relations between these two are very complex, it is not completely understood yet. When the problem of dispersion equation's being partial differential equation is added to this, the solution of the problem becomes even harder. In the second half of the last century, decrease in clean in clean water sources due to pollution, the protection of the existing ones and the above mentioned difficulties of the problem, made the dispersion-longitudinal dispersion subject a popular one and this subject drew the attention of many researchers. Longitudinal dispersion equation, known as Taylor or Fickian model defining the `Longitudinal dispersion coefficient` which represents the two components of dispersion mechanism, is a basic equation accepted almost by all researchers. Since this equation gives very different results from the actual dispersion values in natural rivers, determination of the longitudinal dispersion coefficient to be used together with this basic equation became the purpose of many researchers. Since the solution of the problem in its' present status is almost impossible and it prevents its' usability for the practical engineering purposes, each researcher, in his own experimental environment, obtained longitudinal dispersion coefficients giving results very XVdifferent from each other, by making simplifying acceptances or by neglecting the variables which they see having a small effect. In the 2. Section of the study, Taylor equation is obtained by emphasizing Fickian model, and the reasons for the equation not obtaining close results in natural rivers and channels are discussed. Various longitudinal dispersion coefficient statements obtained until today are given collectively and by which acceptances and hypothesis they are obtained and the results they give in different flow conditions are evaluated. At the end of the section, the statements which are thought to give better results than the others in natural river and open channels are determined and suggested. The solution of longitudinal dispersion equation, which is a partial differential, is obtained by finite elements or finite difference method. With the facilities offered by the progressing computer technology of today, the method does not require much mathematics and physics knowledge which results in the preference of finite difference method. In the 2. section, general information is given about the basis of finite difference method, its' geometric meaning, the ways of solution and the stability criteria, and together with the conversion of the statement into finite difference method, obtained by Savcy which was suggested to be taken as equal to 1 at the beginning of the calculation and in this way which became classic Taylor equation, also the stability criteria are given separately for one and two dimensional solution. Experimental studies of Sayre-Fukuoka on sinuous open channels are examined and longitudinal dispersion coefficient statements they obtained as the result at the end of the experiments, which was stated that they give close results in case it is used with dispersion equation in natural rivers and sinuous open channels, and theorical substructure of this statement and the other results are evaluated. In the 4. Section, the longitudinal dispersion coefficient for a natural river in U.S.A. obtained by Sayre's sinuous open channel model is solved with one and two dimensional longitudinal dispersion equation in the finite differences method. During the solution, the actual and calculated dispersion coefficients, concluding conditions, averaged cross-sectional flow velocities are changed with solution steps, and the solution is repeated; and the solution steps in Microsoft-Excel, which is a calculation table program of this solution, and defined formulas are explained in detail and the results are given as tables and graphs. In the 5. Section, calculation results obtained in the previous section are examined separately and comparatively for one dimensional flows and two dimensional flows. As a result of these solutions, especially within the period of time defined as the initial period, it is seen that two and one dimensional solutions give very different maximum concentration values and formation periods in the chosen spots for the solution. In the 2. Section, it is seen that the statement defined by Fischer is in accordance with two dimensional numerical solution results for the time values in which Taylor equation is valid. It is determined that the results obtained from two dimensional solution become almost equal with one dimensional solution only after this value. Moreover, harmony of the results obtained from numerical solutions with the actual behaviour are compared in tables and graphs and it is understood that the results of the actual behaviour is in harmony with the results of the two dimensional numerical solution. In different situations, the results obtained from one dimensional solution XVIare also compared within themselves and tables and comparative graphs are given for all these evaluations. In short, the following can be stated. a) Especially in one dimensional solutions, even if the system is stable, to make the solution in more frequent and small steps in stead of big step intervals increases the correctness. b) When the average cross-sectional velocity increases, maximum concentration for the low, decreases but the maximum concentration in the sports chosen for the solution increases and it is formed priorly. It is observed that the ratio between returning periods to initial concentration is equal to the ratio between the velocities. c) It is observed that the changes in the longitudinal dispersion coefficient and the concluding conditions has a great effect on the numerical solution results. It is understood from the solved sample solution that the change in the dispersion coefficient changes the results more in the increasing values of the position. d) Without the determination of correct longitudinal dispersion coefficient and concluding conditions, numerical solution is meaningless. For the longitudinal dispersion coefficient, it is determined that the 6 statements emphasized in the 1. section gives good results also the example set herein. Especially, it is seen that the statements found by Liu and Fischer by the acceptance of lateral velocity distribution are almost equal to actual dispersion coefficient. e) Results of two dimensional solution give appropriate and stable results according to the results of one dimensional solution. Especially, if the greater part of the pollution problem happens in the initial period, it is understood that it is necessary to make two dimensional solution hare, because after this period one or two dimensional solution results are very close to each other. xvn 237

ÖZET Bu çalışmada, alttaki geçirimsiz zeminden d kadar yukarıda bulunan ve tabanı su tablasına kadar uzanan bir dren hendeğinin su ile doldurulması sonucu oluşan ve değişik araştırmacılar tarafından teorik veya deneysel olarak incelenen permenant olmayan yeraltı suyu hareketi incelenmiştir. Birinci bölümde yeraltı suyu akımı ile ilgili genel bilgiler Darcy Kanunu esas alınarak verilmektedir. İkinci bölümde yeraltı su yüzeyinin zamanla değişen hareketi ile ilgili genel denklemler konu edilmektedir. Ayrıca, bu bölümde değişik zamanlarda değişik araştırmacıların probleme yaklaşımları ve elde ettikleri ifadeler yer almaktadır. Üçüncü bölümde Richards denkleminin ilgili başlangıç ve sınır, şartlan altında Sonlu Farklar formunda yazılarak elde edilen nümerik çözümü incelenmiştir. Nümerik sonuçlar grafik şeklinde ifade edilmiştir. Özel olarak dw/b = 0.8 için bu çalışmada elde edilen sonuçlar Watson ve Koussis tarafından elde edilen değerlerle karşılaştırılmıştır. IV UNSTEADY DRAWDOWN OF WATER TABLE SUMMARY In this work, by the result of a drain ditch filling with water that is as d value up from impermeable base and its floor level is equal to water table, the underground water movement has been investigated. In this investigation, by the purpose of discussion of underground water movement, the Richard's equation developed for two direction of water movement was used. This diferantial equation was written as from of finite difference and soluted its numerical value. The work is expected to throw light on the contemporary problem of the multi-aspect improvement of grounds which are not usable for agricultural purposes. The drainage of minor lakes, shallow waters and moors having no economic values, the prevention of agricultural lands and inhabitad areas form floods, the removal of excess water that hinders the groth of agricultural plants and of water existing in the hollows of ground, the lowering ground water level of a desired degree for any purpose, the elimination of the water used for washing lands impregnated with salt are among the most important problems of present times especially in countries such as Turkey where agriculture is important. An introduction is made in the first chapter of this study in the following sequence:. The experimental principle ofthe Darcy's Law, the validity range of the Darcy's Law, Definiton of the Permeability Coefficient and its Formulation, Generalization of the Darcy's Law and derivation of the. Basic Equations, Study of the Velocity Potential of ground Water, Study of the Elasticity and Compressibility, derivation of the Velocity Potentiol of ground Water, Study of the Elasticity and Compressibility, derivation of the Differential Equations of the steady flow, derivation of the Differential Equations of the Non- Steady Flow, and the Limit Conditions are discussed.In the second chapter the studies regarding the unsteady movements of groundwater are viewed and it is seen that these studies are generally concerned with the design of drainage systems. Dumm (1954), stated that Glower had discovered an expression by using the Fourier series, for the ground water level height between the drains as follows: 2 2. 4. £ 1 -a m2K t/L2. mx n = - hr, z, - e sın -= - TC m=l,3,5, m L For the horizontal distance between the drains, Luthin (1959) found the formula: cK(t2-t!) X_j - ~- - - - - - hi n(ln^) n2 Kochina (1962) has investigated the unsteady movements of groundwater in the cases where reacharge and evaporation take place and determined the form of the water table for various evaporation rates. Stallman (1962) has analitically studied the unsteady ground water between two parallel drain ditches and determined the drawdown d(x,t) as a functions of time and space in the case where the water levels in the ditches are suddenly lowered by do. The relationship derived by Stallman is; d(x,t) = do(l-7= I e / ce/Y4ÜT ^ -u VIKirkcham (1964) has determined the variation of water table between parallel drains where the flow is transformed to unsteady state by the termination of the reacharge. He has found the following relationship between the time and drawdown by tating the end of reacharge as the time origine: (h0-h) + L'F(x,o) In (-^) t = K n Bear ( 1 972) has found the drawdown d (x,t) as a function of space and time in the case where the water table is orriginally horizontal and flow is created by a sudden drop of dQ in the canal water level; nx2 A/2 d(x,t) = d0erfc(^-) Saydam (1975) has studied the non-steady movement of the ground water in a limited and unlimited two-dimensional water conduit, and suggested a way of solution by means of the finite differences method to determine the ground water level. Skaggs (1975) has applied the one-dimensional version of the Forcheimer's Equation to the ground water flow running down into two drain ditches that are parallel to each other, and determined the geometry of the water surface by using the finite differences method. Koussis (1979) has studied the ground water flow formed in case of a sudden and certain lowering of the water level in a water resevoir which is joined to a water -conduit. Koussis has taken the Forcheimer's equation as the mathematical model characterizing this event. By defining dimensionless entities, he has eliminated any dimensions of this equation and at first transformed the partial derivative, constant-coefficient differential equation of second degree thus formed into an VIIordinary differential equation by a proper transformation of variables, and then solved the equation by numerical methods. Higgins (1980) has studied the non-steady movement of the ground water flow formed in case if the water level in a drain ditch or a reservoir is lowered for a certain amount suddenly, and drawn the variation curves of the ground water level for various constant sections with time. By defining dimensionless entitities. Higgins has, after eliminating the dimensions of the corresponding differential equation and the boundary conditions, and solved the differential equation under the corresponding initial and boundary conditions. Watson and Koussis (1980) have restudied the problem treated by Koussis previnously, and by using the lines methods, solved the problem numerically. During the solution of the problem Forchiemers's equation was used as the one characterizing the flow zone. Savcı (1983) has studied theoretically the unsteady ground water movement caused by a sudden drop, dQ, and found the equation, 2e ? no + 7T n° =0 for the un-steady movement of the ground water surface. In third chapter, in the problems of underground water surface, for two direction movement of water under the concerned starting and baorder conditions of equation that was developed by Richard has been discussing in respect of finite difference method. In the area that was applied finite difference. 1 ). ax = az = 0.05 value is investigated for square-shoped net. 2). As the starting, the water table was assumed that is upas d value from impermeable base and equal to floor height (d=d1) VI3). Time interval (ax) is constant and was taken as value of 0.005. x value was calculated with 0.005 value add. x = x+ Ax 4). For the up boarder provision, the error share should be stated according to willing rate. In the discussing problem the error share has been choosen as ± 0.001. In the result of solution, for the different rate of dw/b, chan ging curves between water table and range has been found for constant times. In this work, as special situation, the found results for dw/b = 0.8 have been compared with Watson and Koussis's values. In this comparison, the curves has been observed different from each other. The causes of difference-stated above as different corves- are starting and boarder conditions and using method for the problems. IX 54

ÖZET Kıyı ve deniz yapılarının, laboratuvarda belli bir ölçekle yapılan modellerinde amaç, projenin minimum maliyetle en iyi performansı göstermesidir. Bu amaçla kurulan modellerde yapılan isler, bu çalışmanın kapsamına alınmıştır. Çalışmanın birinci bölümünde bir limanın en genel tanımı verilerek sınıflandırma yapılmış ve yat limanları (marinalar) hakkında bilgi verilmiştir. Bu bölümde, ayrıca çalışmanın amacı belirtilmiştir. İkinci bölümde, liman model leme çalışmalarında kullanılacak dalga karakteristikleri (dalga yüksekliği, dalga periyodu, v.b.)'nin elde edilmesi için yapılan dalga iklimi çalışmaları anlatılmıştır. Üçüncü bölüm, fiziksel modellere ayrılmış, liman tasarımında fiziksel modellerin yeri ve önemi belirtilmiştir, ölçek seçme kriterleri ile ölçek seçmede kısıtlayıcı faktörlerden sonra, bu çalışmanın yapıldığı iki ve Uç boyutlu model kanal ve havuzları, bu arada da ölçme sistemi tanıtılmıştır. Dördüncü bölümde, açık denizden kıyıya doğru gelen dalgaların dönme, sapma, sığlaşma gibi nedenlerle değişimi ele alınmış, bu konuda yapılmış çalışmalardan söz edilmiştir. Besinci bölüm, kıyı yapılarını etkileyen temel sorunlardan biri olan katı madde hareketine ayrılmıştır. Bu hareketin temel nedenleri etraflıca anlatıldıktan sonra, katı madde süreklilik denklemi ve kıyı boyu katı madde hesabında en çok kullanılan CERC formülü üzerinde bilgiler verilmiştir. Bu bölümün sonunda da kıyı çizgisi değişimlerinin matematik modeli ve sınır koşulları tanıtılmıştır. Çalışmanın altıncı bölümünde ise dalgakıranlar üzerine detaylı bilgi verildikten sonra, dalga etkisi altında meydana gelen hasarlar tanıtılmış ve hasar kriterleri sunulmuştur. Dalgakıranın koruyucu tabakasını oluşturan tasların ağırlığını bulmada kullanılan ve stabilite formülleri olarak adlandırılan formüller ve bu formüllerde stabilite katsayısını etkileyen birincil ve ikincil faktörler anlatılmıştır. Ayrıca dalgakıran tasarımında gözönüne alınması gereken çevresel ve jeolojik faktörler ile risk analizi ve ekonomik çalışmalar hakkında gerekli bilgiler verilmiştir. Yedinci bölümde, yapılan deneyler tanıtılmış ve deney sonuçları verilmiştir. Sekizinci bölümde ise bu sonuçlar değerlendirilmiştir. LABORATORY STUDIES OF COASTAL STRUCTURES AND INVESTIGATION OF GÜZELCE MARINA MODEL SUMMARY The main purpose of a hydraulic model that is set up in a laboratory, is to provide the modelled project, the best performance with a minimum cost. The term `model` is used in hydraulics to describe the simulation of a `prototype`, i.e. field size, situation. The hydraulic engineer uses models to predict the effect of a proposed design or scheme; they are tools for producing technically and economically optimal solutions to engineering problems. In other words, a model is a system which will convert a given input (geometry, boundary conditions, force, etc.), into an output (flow rates, levels, pressures, etc.), to be used in civil engineering design and operation. With the development of hydraulics, the scale-model has played an increasing role in the design of hydraulic structures and coastal works in the United States since about 1930. Important model techniques and procedures have been developed, instrumentation has improved, and simulation of more complicated phenomena has become possible through experience and basic research. Engineering experience and the use of analytical methods in the solution of design problems are still important factors in the design of engineering works. For many of the complex problems in coastal engineering, especially those corcerning the effects of wave action, the best approach to the problem of obtaining aspects of design is the use of scale models and the formation of a close alliance between the design engineer and the laboratory engineer. Hydraulic engineering projects include different types of studyas in the other engineering disciplines. These are; (i) Office studies, (ii) Laboratory studies and (iii) Field studies. The aim of this research is to determine the minimum weight of units which are used in the armour layer of a breakwater under the effect of incident waves. In chapter 1, general information about the ports and marinas is given. Chapter 2 includes the Wave Climate Studies which is aimed to determine the characteristics of incident waves, i.e wave height, wave length and wave period. The size of a wave for a particular location will depend on the velocity of the wind, the duration of the wind, the direction of the wind, the greatest distance over which the wind can act, and the depth of the water. xiiIn determining the wave to be used in the design of a structure at a particular location, only in exceptional cases will the designer be able to rely on a complete set of observations stretching over a sufficiently long period of time. Since World War II considerable work has been done on the forecasting of tide and wave conditions from meteorological, oceanografic, and geographic data. After the war, the advent of offshore structures for oil wells and radar stations kept research work going. The average height of the highest one-third of the waves for a stated interval has been termed the significant height, and it has been found that the highest or maximum wave has a height of about 1.87 times the significant height. In chapter 3, a detailed information about the physical models is given. Physical models provide the engineer and scientist two significant advantages when studying a particular coastal engineering problem. The first is that nature is used to integrate the appropriate equations which govern the phenomena, whether it be wave propagation into harbours or sand transport on a beach. No simplifying assumptions are used and no unknowns are omitted, as often occurs in analytical or numerical modelling. The second advantage is that the size of the model is much smaller than the prototype, permitting the easier acquisition of relevant data. There are, of course, drawbacks, such as the introduction of scale effects, which are due to changes in the relative importance of various forces (such as surface tension) as the model becomes smaller than the prototype. Additionally, the model is generally more simplistic than the prototype, for example, the use of monochromatic (single frequency) waves to study real sea states or, since the advent of spectral wave generators, using `real` sea states, but neglecting wind and other potentially important forces in nature. In coastal engineering, there are two types of model commonly used, fixed bed models (to study, for example, wave propagation and currents) and movable bed models (to study the deposition and transport of sediment). The modeling criteria for each are different. Chapter 4 deals with propagation of water waves. The breaking wave height and breaking wave angle are fundamental quantities required in coastal engineering applications corcerning the longshore current, longshore sediment transport and nearshore environment in general. Information about the local wave heights and wave directions enables a designer to estimate the wave forces and elevations to be expected at a structure or a shoreline. Before breaking, waves behind coastal structures transform under diffraction, refraction and shoaling. It is assumed that the breaking wave height behind an obstacle is proportional to the product of 3 coeffients calculated with linear wave theory: (1) A diffraction coeffient, Kjjj», for waves emanating from the tip of a long breakwater in uniform depth; and (2) & (3) refraction and shoaling coefficents, % and K^, as given, respectively, by Snell's Law xiiifor a bottom with straight and parallel contours and by energy conservation. The location of the point of breaking, is determined by the breaking criterion. The following simple breaking criterion is used as a representative one: Hb-$db (1) in which typically (3=0.78. The breaking wave height is known to depend on the bottom slope and incident wave steepness. In Chapter 5, coastal sediment transport is discussed and coastal erosion is explained. Coastal erosion is caused by diverse factors. These include rise in mean sea level, increase in severity of incident waves, change in local magnitude and direction of incident waves, loss of sediment supply from rivers and cliffs, and interruption of the local littoral drift by the structures. If the cause of undesirable erosion in an area cannot be eliminated or corrected, then buildings, roads and other resources will eventually become endangered, and some degree of shore protection must be undertaken. The shore can be protected against erosion through the use of coastal structures, nonstructural procedures, such as beachfill, or a combination of structures and nonstructural methods. In situations where extensive damage may occur because of storm waves and water instrusion, or where nonstructural procedures are not feasible, then seawalls, bulkheads, and coastal dikes are commonly constructed for beach erosion control and for preventing inundation. Numerical models provide a powerfull means for making quantitative estimations of shoreline evolution. In particular, the so-called `one- line` numerical model has been widely applied in recent years. The term `one-line` typically refers to the shoreline; therefore, this model is often called `shore-line` model. The purpose of the shoreline model is to simulate long-term evolution of the shoreline or the beach planform. The governing equation for the shoreline position is obtained from the continuity equation for beach sediment (assumed to be cohesionless sand). A predictive formula for the sand transport rate is necessary to solve the governing equation. Sand transport and the resultant shoreline change depend on the local wind, waves, and currents, beach planform, boundary conditions, and constraints such as the one produced by a seawall. It will be assumed here that the longshore sand transport is produced solely by obliquely incident waves ; other transport mechanisms are possible, such as coastal, tidal, and wind-generated currents. It will be sufficient to use the equation for the shoreline position in its most basic form: xivwhere y : shoreline position, m t : time, s D ' : depth of closure, m Q : volume rate of longshore sediment transport, mJ/s x : distance alongshore, m `3, In order to solve Equation 2, three kinds of information are required : (a) the initial location of the shoreline with respect to some coordinate system (Figure 1) in which the x-axis is oriented along the trend of the coast and the y-axis points offshore, (b) an expression for the longshore sand transport rate, Q, and (c) boundary conditions for either y or Q at the two lateral ends of the beach. Of these, the initial position of the shoreline is readily obtained or assumed. ? LATERAL BOUNDARY CONDITION: JETTY LATERAL BOUNDARY CONDITION: NATURAL (FIXED I BEACH- SEAWALL r /.? / 77, > '''>> Vv are the specific weights of armour and water, a is the breakwater slope measured from the horizontal, Kj being empirical stability coefficient and Hp is the zero damage (1% to 5% damage) design wave height. As may be seen equation 4 does not include the effect of wave period in its prediction of armour weight. In chapter 7, laboratory experiments are explained and the results are given. The results of the stability experiments are plotted where the abscissa shows the percentage damage DT, defined by equation 5. DT - total number of displaced armour units total number of armour units used in the test section (5) The results of the experiments realized to predict the water level fluctuation are given with a dimensionless parameter (K), defined by equation 6. K _ Wave height in the harbour basin,^ incident wave height In chapter 8, the evaluations of the experimental studies and the conclusions obtained from these evaluations are presented. These are as follows. For the stability experiments: 1. Incident wave height and period are the main factors that affect the damage on the armour layer of the breakwater. The higher the incident wave and the greater wave period, the greater is the damage on the armour layer of the breakwater. xvi2. In the economical life of the structure the occurence probability of a wave with a height equal to or greater than the project wave height is calculated according to the risk formula and consequently the damage that will occur on the armour layer of the breakwater can be seen and the dimensions (i.e. the weight) of the stones, which will be used in the armour layer, can be determined. 3. The weight of the stones which will be used in the armour layer must be the same along the breakwater axis in relatively equal water depth. 4. The dimensions of the structures are defined separately whether their locations are in or out of the breaking zone. For the water level fluctuation experiments: l.The water level fluctuations in the harbour basin must be examined on the 3 dimensional laboratory model under the effect of the incident wave from the effective direction for the water level fluctuation. 2. For the conditions when the effective direction (s) can not be examined on the 3 dimensional laboratory model, this effect can be controlled by using the diffraction charts given in [ 2 ]. 3. The appropriate layout of the harbour for the water level fluctuation must be examined on the 3 dimensional laboratory model for both the coastal sediment and sea surface, pollution. 4. Because the waves in the entrance of the harbour are the main causes of the water level fluctuations in the harbour basins, the determination of the angle between the tip of the main breakwater and the effective direction will be the best way to control these fluctuations at the desired level. xvi i 130

ÖZET Bu çalışma, bir sulama kanalı boyunca kanal kenarına yerleştirilen yansavakl ardan, sulanacak bölge için yeterli miktarda ve eşit şekilde su alınmasını sağlayacak kanal ve yansavakların projelendirme şekli hakkındadır. Bir çok sulama bölgesinde büyük ana kanallar ve su alma yapıları inşa edilmesine rağmen bütün sulayıcılara sulama suyunun istenilen miktarda ve zamanında erişemediği bir gerçektir. Bunun nedeni, gösterişli büyük barajların ve sulama kanallarının planlanmasına büyük önem verilmesine karşılık sulama projelerinin su dağıtım tekniği yönünden yetersiz planlanması ve su dağıtımında büyük önem taşıyan su alma ağızlarına planla mada hiç önem verilmemesi veya kaba yaklaşımla boyut lan- dırı İması olduğu söylenebilir. Bu durum yetersiz ve ada letsiz bir su dağıtımı yanında büyük su israfına neden olmaktadır. Sulama şebekelerinde sulama suyunun dağıtımı, su miktarını ve su seviyesini düzenlemek suretiyle gerçek leştirilebilir. Bu çalışmanın birinci bölümünde, kenarında bir yan- savak bulunan bir açık kanaldaki akımın özellikleri, genel hesap esasları ve uygulanan tertip şekilleri hakkında bir takım faydalı bilgiler verilmiştir. İkinci bölümde, yansavaklarla ilgili yapılmış olan çalışmalar hakkında özet bilgiler aktarılmıştır. Üçüncü bölümde, öncelikle incelenecek problem tanı tılmıştır. Sonra laboratuvarda mevcut kanal içine bir deney kanalı inşa edilmiş ve daraltma faktörü esas para metre olarak seçilerek deneysel çalışmalar yapılmıştır. Deney ölçüm değerleri ve bunlara ait hesap sonuçları da bu bölümde verilmiştir. Çalışmanın dördüncü bölümünde deney sonuçlarının değerlendirilmesi yapılmış ve gerekli öneriler sunulmuştur. -XII- SUMMARY DESIGNING OF LATERAL WEIRS HAVING A UNIFORM WATER SUPPLY This study is about lateral weir which is set up along the canal which ensures obtaining sufficient and equal amount of outflow from the canal by defining optimum canal shape. In our everyday life, water, being one of the few resources, is getting its significant continiously. Due to rapid population increase and rising of life standarts, intake and planning foundation in many parts of the world are obliged to distribute limited water potential in a bit more rational fashion and to use its work up tecnique in a best way. Inspite of irrigation of large main canals and contraction of intake, its a fact that irrigators do not get the necessary amount of water and the supply does not reach in time. Because of this, irrigation projects water distribution techniques may have inadequate planning and no importance to water inlets planning which is important in water distribution or approximate approach to designing. In this situation, besides inadequate and unequal water distribution, a big loss results as well. In the sense of improving water distribution of a network, all the problems arising in the distribution of water through a canal network in a desired manner may be understood. Distribution of water through water canals, water quantity and water levol can be nchlvod in an adjusted way. Water level from point of view of water distribution In canals having adjusted water level get a great importance. Due to the function of outflow, the water level in the open canals having free surface flow, by the irrigator regulators it is possible to adjust the quantity of water. In this text, test data related to uniformly discharging lateral weirs are presented. Uniform weir outflow conditions were obtained by altering the geometric parameters of weir system. The outflow through the lateral weir model was obtained on the basis of the hydrodinamic model. -xiii-In the first chapter, some useful knowledge about the characteristics of flow in open canal with lateral weir on the side of canal, basic calculation rules, and apl icat ion of designed shapes are presented. Due,to complexity of flow and outflow in the vicinity of lateral weir, no definite solution is found till now. Because of this, investigators have made experimental studying and have researched about lateral weirs problem by means of some assumptions or theortical studies. We must know that the lateral weirs are short in size. Otherwise, due to secondary flow which occurs along the lateral weir and other energy loss, constant energy level idea is wrong. During the test, the energy level of fluid along lateral weir is assumed constant. Because of different flow regimes in the free canals and changing in flow depth at the end of lateral weir acording to the critical depth, water surface profiles occur in different shapes along lateral weir. The relation between quantity of water which flows through canal with a constant energy level and depth of water can be explained by `KOCH PARABOLA`. If the flow depth at the beginning of lateral weir is higher than critical depth (subcritical regime), then the flow depth in the main canal increases along lateral weir. After that swelling which occurs at the end of lateral weir decreases towards end of the canal and becomes equal to the critical depth. If the flow depth at the beginning of lateral weir is lower than critical depth (supercritical regime), then the flow depth in the main canal decreases along lateral weir. Next, flow depth increases from at the end of lateral weir and reaches to a uniform flow depth. The lateral weirs may be constructed parallel to the canal axis or at a definite angle. In practice, usually, it is constructed in a manner in which weir crest is parallel to the canal floor. Sometimes, the lateral weir may be set up at a positive or negative slope acording to the canal floor. Designed shape of the lateral weir affects output (discharge capacity). On the other hand, the profile of weir crest may be plain, sharp crested or lifted nappe form. Sharp crested profiles are applied on the models and small foundations. The studies about lateral weirs have been started at the end of 19. th century. Preliminary studies were usually experimental and as a result of these, some -XIV-emprical formulas developed that are still used in practice. In the course of time, investigates started theoretical studying, and theoretical results were compared with experimental studies. In these experimental studies, rectangular sectional canals were used more. After that, theoretical analysis were developed by considering rectangular section. In the first chapter: First of all, lateral weir problem was explained. After that, conditions of obtaining irrigation water from uniform elevation by use of lateral weirs contructed at specified intervals along the canal of vertical profile where water flows in subcritical regime, were studied experimentally. Theoretical approaches were expressed firstly, and experimental studies carried out by choosing contouring factor as a basic parameter. In order to approach the problem theoretically, it is convenient to examine an equivalent single lateral weir in place of multiple weirs housed on the side of weir. It is reasonable to assume that the outflow through individual weirs of a system of multiple weirs will be equal when the water surface elevation in the canal is uniform along the reach that spans the weirs, when the weir parameter, F, is held constant. o The level of flow in the canal decreases continiously. This problem could be prevented (or decreased) by some geometrical variations. These are presented following, respectively. a - ) Contouring of the canal side b - ) Rise in the canal bed. To provide uniform water surface along the canal on the weir crest in case of side contouring and bed rising which depend on rates of discharge and amount of contouring two new dimensionless indicators R and R are mentioned. Q Q w w Q Q 1 _ 1 Rb = b ' Rh ` IT 3 Q : Lateral weir discharge (m /s) w 3 Q : Main discharge in the canal (m /s) i b : Amount of side contouring (cm) B : Canal width (m) l z : Amount of bed rising (m) -xv-When the variable R has the value of unity, the D water surface profile will be horizontal in the canal reach spanning the weir, for case where side contouring is undertaken. Smilarly when the variable RHhas the value of unity, the water surface profile will be horizontal in the canal reach spanning the weir, for the case where side contouring is done. Because of this, variable is useful in the analysis of the experimental data. In this study, only contouring of the canal side condition was investigated because of time insufficiency. For experimental study of the problem a test canal was set up in the Hydraulic and Water Structures Laboratory at Istanbul Technical University. A 26 m. long, 98 cm. wide and 45 cm. high canal of the rectangular profile, which is already avalaible in the lab, was divided in two parts by use of reinforced concrete plates and 3 lateral weirs were placed at 335 cm. intervals. At the inlet, canal's width was adjusted to 30 cm. up to the first lateral weir, and, since the side wall of the test canal was built as to permit adjustment acording to desirable width, a gradual contouring was provided as from the first lateral weir up to the last one. The side weir is contructed as a sharp crested weir of variable size, the length and heigth of the weir is varried by the addition of fibre glass plates. The incoming water from the upper tank enters the initial part of the canal by gravity. In the mean time, the flow is calmed by various things such as perforated iron plates, submerged baffles and floating wooden plates. A 60° triangular ganging weir was used to determine the discharge of weired water from the lateral weir. Water height on the crest of weir which is required for discharge calculations was measured by use of limnimeter which was moved in the direction parallel and perpendicular to the canal axis so that water depth at the beginning of canals can be measured and changes on water surface through canal reach spans can be determined. After weired from lateral weirs, the remaining water in the main canal continues its journey and pours to the measurement bin at the downstream of canal. Quantity of poured water is defined by 90° triangular weir and water flows to lower bin. Test were held for three positions of side contouring and non-contouring position. -XVI -The side contouring positions are; 1 - l.st side contouring position (b=3, 3, 3) cm 2 - 2.nd side contouring position (b=l. 5, 4. 5, 7. 5) cm In each side contouring, sill height was altered for two times to be s = 15.00 cm, and s = 17.00 cm, and weir width was altered for three times to be L = 14 cm, L = 17 cm, L = 20 cm in each sill heigth. In addition all of these experiments were made with both control gates where at the end of canal opened and partly closed positions. During all tests, flow in the canal was kept constant in the subcritical regime (F < 1). In all the tests, Froude numbers at the in let were limited between 0.12 and 0.69. The outflow from lateral weir was changed between 14 lt/s and 75 lt/s. Test results are listed in tables and graphs. In the fourth chapter, the results of tests were evaluated and some suggestions were recomended. Water surface profiles which occur on weir reach spans as a result of contouring on the side of the canal are horizontal when dimensionless parameter R close to 1 and water surface profiles are less horizontal when dimensionless R is not close to 1. This condition can b be obviusly observed for 2.nd and 3.rd side contouring positions. When the sill height is increased, usually, flow speed at the inlet (V. ) increases, and outflow from lateral weir decreases. In the test results and graphs indicating the relation ship between theoretical discharge and test discharge it is observed that there is a harmony and a link between theoretical lateral weir discharge which was obtained by the use of hydrodynamic model, and that of lateral weirs in case of side contouring. While the control gates are open, the difference between the theoretical and real outflow from lateral weir increases because of downstream conditions. A favorable condition is taking enough quantity and each equal to another outflow from lateral weirs. From the point of wiev of outflow rates, more suitable results are observed at 2.nd and 3.rd side contouring positions when the outflow taken from 2.nd and 3.rd lateral weirs are compared to the outflow of l.st lateral weir. For outflow from lateral weirs: There is an avarage (3 - 4) % deviation on the 2.nd -XVII -lateral weir and 8 % deviation on the 3. rd- lateral weirs, when compared to the l.st lateral weir. This deviation reachs (18-20)% at the non-contouring position. The rates of outflow taken from lateral weirs acording to the quantity of water in main canal is presented in Table 4.3. The rates are very low, and water loss increases at the non-contouring position. On the other hand, water loss is very few at the 3.rd side of contouring position In practice, water distribution system with optimum side contouring ensures economic use of water. Moreover, due to side contouring, cross section of canal reduces, so the cost of canal reduces as well. -XVIII - 154