Yazar "Aydemir, Alper" seçeneğine göre listele

Listeleniyor 1 - 17 / 17
  • [ X ]
    Öğe
    A study on three different hydropower operation rules by monthly and daily time steps
    (Ice Publishing, 2021) HaktanIr, Tefaruk; Aydemir, Alper; Acanal, Nese
    Operation simulation models are developed for monthly and daily time steps for computing the hydroelectric energy and its financial benefits in an economic life by three different operation policies: steady-rate, three-shift and pumped-storage rules. The pump is operated during the night and consumes low-cost energy. The resulting computer programs, three on monthly and three on daily steps, are applied to the Yamula dam - which is a fairly large dam generating energy, located in the Inland Anatolia region of Turkey - over a period of 35 years using the gauged daily stream flows and daily pan evaporations. The results indicate that the pumped storage is more profitable than the other two rules aside from the intangible benefits of regulating the within-day fluctuations of demand for electrical energy. Another result is that both the average annual energy and the financial benefits given by the three rules computed by the monthly time steps are about 1-2% greater than those given by the daily time steps. This study is the first one comparing all these three operation schemes quantitatively in a realistic way both in monthly and daily time steps.
  • [ X ]
    Öğe
    Baraj güvenliği için risk analizi yazılımı
    (Uluslararası Katılımlı III. Baraj Güvenliği Sempozyumu Bildiri Kitabı, 2012) Aydemir, Alper; Güven, Aytaç
    Günümüzde küresel ısınma nedeniyle yenilenebilir enerji kaynaklarının önemi her geçen gün artmaktadır. Ülke ekonomisine önemli katkısı bulunan su kaynaklarının verimli kullanılması yeni istihdam alanları yaratabileceği gibi mevcut olanakların geliştirilmesinde de önemli rol oynamaktadır. Barajların, tarım arazilerinin sulanması, elektrik enerjisinin üretimi, taşkın kontrolü, balıkçılık, iç sularda ulaşım gibi pek çok faydaları bulunmaktadır. Barajların bu önemli özelliklerinin yanında baraj yıkılması sonucunda çok ciddi can kayıplarına ve maddi hasarlara yol açabilecekleri unutulmamalıdır.Baraj güvenliği açısından oluşabilecek tehlikelere karşı risk analizleri bütün barajlar için yapılmalı ve baraj durumları sürekli olarak izlenmelidir.Bu çalışmanın amacı risk analizi yazılımı geliştirerek, baraj güvenliğinin Türkiye’deki durumunu belirlemektir. Bu kapsamda, öncelikle farklı ülkelerde baraj güvenliği konusunda yapılan çalışmalar araştırılmış ve kullanılan çeşitli yönetmelikler incelenmiştir. Çeşitli baraj türleri için tehlike oluşturabilecek parametreler belirlenmiş, baraja yakın bölgelerde yaşayan ve olası bir yıkılma durumunda etkilenebilecek insan sayıları, bölge haritaları ve nüfus bilgileri kullanılarak belirlenmeye çalışılmıştır.Risk analizi için Utah Üniversitesi tarafından Federal Emergency Management Agency’nin (Fema) kullanımı için hazırlanmış olan EXCEL tabanlı risk analizi yazılımı (FEMA Risk Tool) kullanılmıştır. Yazılım baraj yüksekliği, baraj gövde türü, dolu savak kapasitesi, ortalama yıllık yağış miktarı, ana kanal uzunluğu, ortalama havza yüksekliği gibi temel baraj karakteristiklerini kullanmaktadır. Herbir baraj türü için risk analizinde kritik öneme sahip değişkenlere göre analiz yapılmıştır. Örneğin toprak dolgu barajlar için yıkılma modları, taşkın, deprem, normal stabilite ve sızıntı durumlarıdır.Yazılıma gedik genişliği hesabı, yıkılma süresinin belirlenmesi, çıkan en büyük debi miktarının bulunması için kullanılan ampirik yöntemler ve gedik şev eğiminin bulunması için kullanılan çeşitli metotlar da eklenmiştir. Geliştirilen bu yazılım kullanılarak Türkiye’deki bir baraj üzerinde risk analizliyapılmıştır. Yapılan risk analizleri sonucunda oluşabilecek tehlikeler 3 farklı kategoride toplanmıştır. Bunlar yüksek tehlike, önemli tehlike ve düşük tehlike durumlarıdır. Yapılan çalışmanın sonucu olarak önemli risk parametreleri ve oluşturabilecekleri tehlike durumlarına göre grafiksel sonuçlar elde edilmişve eklenen yeni metotlar için de grafikler hazırlanarak sonuçlar yorumlanmıştır.,Nowadays importance of renewable energy sources increased due to global warming. Effective use of water resources can play important role on economics; this can create new employment areas and helps improvement of existing possibilities. Dams have benefitable functions such as irrigation, hydropower, flood control, fisheries, and navigation. Besides these important benefits, dam failures can cause loss of life and financial loss. Safety risk analysis must be done for each dam and monitoring of dam situations examined continuously.The purpose of this study is to examine the safety of a dam in Turkey by performing risk analysis Firstly different dam safety researches are investigated and all available methods are searched. Dam failure parameters for different kinds of dams are identified. People who live in areas near dams, and the number of people affected in case of a possible collapse of the region are determined using maps and census data.For risk analysis purpose, an Excel based risk analysis tool was used. This tool was created by UTAH State University for the use of Federal Emergency Management Agency (FEMA). This software uses main dam characteristics such as dam height, body type, spillway capacity, mean annual precipitation, main steam length, and mean basin elevation. Risk analysis has been done by using critical parameters for each type of dam, for instance, important failure modes of earth fill dams are flood, earthquake, normal stability and piping.New features such as peak dam breach width, failure time formulas, peak breach discharge empirical formulas and breach side slope calculation methods are also added to the existing tool.In this study, risk assessment of a dam in Turkey has been made by using improved risk analysis software. As a result of risk analysis, hazard situations are classified on 3 different categories. These are high hazard, significant hazard and low hazard. Important risk parameters and failure results of these parameters are shown on graphics. New graphic results are drawn for new methods added on software. All graphical results are discussed.
  • [ X ]
    Öğe
    Baraj yıkılma modellerinde kullanılan debi tahmin yöntemlerinin karşılaştırılması
    (Harran Üniversitesi Mühendislik Dergisi, 2017) Aydemir, Alper; Güven, Aytaç
    Barajların elektrik üretimi ve sulama gibi alanlarda elde edilecek faydaları ile ülke ekonomilerine katkılarının yanı sıra çevre düzenlemesi, ulaşım ve taşkın koruma gibi alanlarda da faydaları bulunmaktadır. Ancak oluşabilecek aksaklıklar baraj yapılarının yükseklikleri ve aktif depolama hacimlerinin büyüklüğüne göre farklı seviyelerde tehlikeler meydana getirmektedir. Özellikle baraj alanlarına yakın yerleşim bölgeleri için barajlarda oluşabilecek yıkılmanın önceden minimum hata ile tahmin edilebilmesi hayati önem taşımaktadır. Bu çalışma baraj yıkılma modellerinde kullanılan debi tahmin yöntemlerinin temel amaçları, hesap yöntemleri ve uygulama alanları ile elde dilecek sonuçların karşılaştırılmasını içermektedir. Literatürde bulunan ve bu araştırmada incelenen yöntemler tarihi baraj yıkılma verilerine istatistiksel regresyonlar uygulanarak elde edildiği için bazı durumlarda yetersiz kalmaktadır; özellikle bu verilerin elde edildiği baraj türlerinin (baraj yüksekliklerinin) tüm barajları içermemesi sebebiyle önerilen regresyon denklemlerinin yüksek belirsizlikleri olduğu görülmektedir. Dams have benefits such as electricity generation and irrigation for national economy as well as recreation, transportation and flood prevention could be given as other benefits. However, possible failures could cause different level hazards according to dam height and active storage volumes of dams. Especially for people living in inundation zones of dams, it is essential to predict dam breach simulations with lowest uncertainty. In this study, dam breach peak discharge prediction methods are compared based on their principles, applications and formulations. Since the methods obtained from the literature were derived from regression analysis of historical dam failures, these methods are insufficient in some situations, especially the historical data used in these studies does not include all dam failures or some types of dam data are missing. Hence, it is obvious that regression equations include high uncertainty.
  • [ X ]
    Öğe
    Dam Breach Parameter Estimation: Case Studies
    (Springer, 2020) Güven, Aytaç; Aydemir, Alper
    Numerical investigation of existing breach parameters could give opportunity to compare dams with each other. This chapter presents five case studies on the applications of breach parameter evaluation methods. The findings obtained by using different prediction methods are compared. The authors conclude by adding general suggestions and ideas for future development of the methods. © 2020, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG.
  • [ X ]
    Öğe
    Dam Failure Modelling Parameters
    (Springer, 2020) Güven, Aytaç; Aydemir, Alper
    Peak breach discharge occurring upon dam failure is an essential parameter for dam safety studies. In literature there are many methods for predicting peak breach discharge. The methods, together with the most widely used dam breach parameters, are described in this chapter, together with the relevant formulations and definitions. © 2020, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG.
  • [ X ]
    Öğe
    Dam Safety
    (Springer, 2020) Güven, Aytaç; Aydemir, Alper
    Many definitions about risk can be found in the literature, so that this section aims to give general definitions used in literature and a theoretical overview as well as the definition of risk used in this book. Definitions used for risk in a very wide range of issues are given in following sections. Unpredictable future creates a problem for engineers during dam projects. These could be identified by engineering investigations. But obtained data must be categorized for easily using in future studies. Definitions for most common terms used in risk studies are given in this chapter. Some of them are: risk, hazard, risk assessment, hazard classification and failure modes. This chapter describes the most common used definitions for these terms. The most probable failure modes are described with recommended actions. Also, problems and solutions for urgent actions in various situations are analyzed. © 2020, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG.
  • [ X ]
    Öğe
    Dams
    (Springer, 2020) Güven, Aytaç; Aydemir, Alper
    Water play vital role in all known forms of life, so the effective use of water resources is an important subject for human life. In this chapter the main properties of existing dams are given with historical data. Definition for small dams is not common around the World. Almost all countries have published definitions for small dams but they all vary from each other. Therefore, a definition of small dams is given. While using dams there could be negative impacts on environment. Some of them are negligible but if not controlled some of them could be very harmful. Detailed information about environmental negative impacts of dams are described in this chapter. © 2020, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG.
  • [ X ]
    Öğe
    DETERMINATION OF MONTHLY WIND SPEED OF KAYSERI REGION WITH GRAY ESTIMATION METHOD
    (IEEE, 2019) Citakoglu, Hatice; Aydemir, Alper
    Wind has been used to facilitate human life throughout history, but besides being a beneficial renewable energy resource it could transform into a hazardous disaster which could result high loss of life and property. The wind energy was first used for purposes such as produce cereals, transport sailing ships in the sea. Nowadays, wind energy is used in electricity production. The temporal spatial variability and difficulties faced during measurement process of wind speed increased the importance of studies related with wind speed forecast. In this study, Gray estimation method was applied to monthly wind speed data measured between 2000-2017 years at three weather stations in Kayseri. Three different GM(1,1) equations were obtained from results of analysis. The average of coefficients obtained from GM(1,1) equations were used to forecast monthly wind speed data between 2014-2017 of other six weather stations located in Kayseri. Accuracy of wind speed estimates were investigated with statistics mean absolute error (MAE) and root mean squared error (RMSE).According to MAE and RMSE criteria, GM(1,1) model has the best result in 18207 station (MAE: 0.28; RMSE: 0.32), while the worst result in 18457 station (MAE: 1.93; RMSE: 1.99). Results of the study indicated that the forecast of wind speed for locations without measurement could be accurately predicted with GM(1,1) model obtained from the other near stations.
  • [ X ]
    Öğe
    Evaluation of wind comfort with computational fluid dynamics simulations for pedestrian sidewalks around buildings
    (Hungarian Meteorological Service, 2023) Aydemir, Alper; Karahuseyin, Fikriye Ezgi; Yilmaz, Yasar Can
    Wind power could be one of the most clean and powerful renewable resources for electrical energy production, but on the other hand, uncontrolled wind flow especially in urban places could cause undesired situations as damage to buildings, decrease in pedestrian comfort, environmental damage, or even life loss. Construction of high-rise buildings, widely spread structures within cities, and environmental changes forces, engineers to find quick, reliable, and also economically viable solutions during design stages, but wind comfort of sidewalks generally not considered enough even if they are located in crowded areas. The web-based computer aided engineering (CAE) program named Simscale which runs on the basis of sophisticated graphical interface was used as computational fluid dynamics (CFD) software to determine wind speeds under influence of buildings in the Nuh Naci Yazgan University campus. Also, field measurements carried out in campus area for a short term period were compared with long term hourly wind speed data obtained from the Turkish State Meteorological Service (MGM) station located in Kayseri to identify most optimal wind speed data for the research area. Results of analysis showed that wind speed increased in the mostly used paths of campus, which means that the layout of buildings negatively affected the wind comfort. CFD analysis softwares could be used to determine the possible consquences of wind with less economic investment in a short time, and they could be used in accordance with comfort criterias as well as safety regulations.
  • [ X ]
    Öğe
    Kayseri meteoroloji istasyonunda gözlenmiş standart süreli yıllık maksimum yağmur serilerinin frekans ve trend analizleri
    (2022) Haktanır, Tefaruk; Aydemir, Alper; Çıtakoğlu, Hatice
    Meteoroloji Kayseri Bölge Müdürlüğünce 1950 – 2019 arası süreçte ölçülmüş 14 standart süreli yıllık maksimum yağmur (YMY) serilerine frekans analizi uygulanmıştır. 5 dakikadan 24 saate kadar 14 ardışık süreli YMY serilerinin her birine Chi2 (Kiy-kare), Kolmogorov-Smirnov ve Probability Plot Correlation Coefficent (Olasılık Çizgisi Korelasyon Katsayısı, OÇKK) uygunluk testleri yapılmıştır. Bu üç testin ağırlıklı olarak değerlendirilmesi sonucu, parametreleri olasılık-ağırlıklı momentler yöntemiyle hesaplanmış, Pearson-3 olarak ta bilinen, 3-parametreli gama olasılık dağılımı (P3-OAM) en uygun model olarak belirlenmiştir. Kayseri için 5 dakika ile 24 saat arası 14 standart süreli yıllık maksimum yağmur olaylarının, 2 yıldan 10 Bin yıla kadar çeşitli ortalama tekerrür periyotları için frekans tabloları ve şiddet-süre- tekerrür eğrileri oluşturulmuştur. Herhangi bir zaman serisinin belirli bir olasılık anlamlılığında trendi olup olmadığını belirlemek için, Mann-Kendall, Lineer Regresyon, Yenilikçi Şen yöntemleri yaygınlıkla uygulanmaktadır. Anılan YMY serileri ile bu üç yöntem kullanılarak yapılan trend analizleri sonucunda, Kayseri’de 1950 ile 2019 yılları sürecinde gözlenmiş olan 5 dakikadan 24 saate kadar 14 standart süreli yıllık maksimum yağmur serilerinde % 5’lik hata payı ile (% 95 anlamlılıkta) ‘artan trend’ olduğu belirlenmiştir.
  • [ X ]
    Öğe
    Modified risk assessment tool for embankment dams: case study of three dams in Turkey
    (Taylor & Francis Ltd, 2017) Aydemir, Alper; Guven, Aytac
    Dam failures are catastrophic accidents resulting in property damage and loss of life. Risk prioritisation systems should be used in accordance with dam safety regulations to prevent these disasters. The purpose of this paper is to develop a risk assessment software which can be used by the decision makers for ranking of dams. Risk assessment was conducted on three embankment dams from Turkey to obtain information about the dam performance based on piping, earthquake, normal stability and flood failure modes. Parameters are incorporated into the programme to develop a new model that could predict variables such as breach width, dam failure time, side slope and peak breach discharge. The proposed tool gives flexibility to choose dam elements for describing the primary features of the evaluated dam; so users can make hazard categorisation of dams according to their risk level which is based on unique project conditions.
  • [ X ]
    Öğe
    Preface
    (Springer, 2020) Güven, Aytaç; Aydemir, Alper
    [No abstract available]
  • [ X ]
    Öğe
    Risk assessment of dams
    (Springer, 2020) Güven, Aytaç; Aydemir, Alper
    Risk assessment process of dams can be time-consuming and may require high investments. If risk value of every dam is defined, then the resources could be shared more efficiently. Descriptions of evaluation procedures for various failure modes such as piping, flood, earthquake and stability are described in this chapter. Consequence assessment procedures are presented in detail, together with the steps of the risk evaluation process, thus helping to identify the appropriate failure mode for examined dam. Moreover, the evaluation of dam safety failure modes with the appropriate life loss potential procedures is described in this chapter. © 2020, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG.
  • [ X ]
    Öğe
    Risk assessment of dams [2]
    (Springer, 2020) Güven, Aytaç; Aydemir, Alper
    [No abstract available]
  • [ X ]
    Öğe
    Simulation Models for Hydro-Electric Energy by Steady-Rate and Night-Shift-Pumped-Storage Operations
    (Turkish Chamber Civil Engineers, 2023) HaktanIr, Tefaruk; Aydemir, Alper
    New operation simulation models for hydroelectric energy and its financial benefit over an N-year period in daily time steps by the steady-rate and the open-loop night-shift-pumped -storage rules are developed. These models are applied on 11 existing dams in Turkiye, which reflect a wide range of hydrologic and hydraulic peculiarities, for regulations between 90% through 40% and the outputs are compared. Regulation is the ratio of (outflow for energy generation, hm3/day) / (average inflow, hm3/day). The present worth of energy benefits and of that of pumping costs computed with a discount rate of 9.5% over a 35-year period yield that the night-shift pumped-storage operations are more profitable than the steady-rate rule. Finally, generalized regression equations for average annual produced energy and for present worth of net benefits by both operation rules against statistically significant explanatory variables are developed using the results of these 11 dams, which are all meaningful by relevant statistical criteria.
  • [ X ]
    Öğe
    Toprak dolgu barajlar için risk değerlendirmesi
    (Uluslararası KatılımlıIV. UlusalBaraj GüvenliğiSempozyumu Bildiri Kitabı, 2014) Aydemir, Alper; Güven, Aytaç
    Dünya nüfusundaki hızlı artış ile doğru orantılı olarak insanların suya olan ihtiyaçları da artmaktadır. İnşaat mühendisliği alanındaki gelişmeler daha yüksek barajların yapılmasına ve baraj göllerinde tutulan suyun geçmiş yıllara göre çok daha büyük miktarlara ulaşmasına imkân sağlamaktadır. Barajların sulama, elektrik enerjisi üretimi, taşkından koruma ve içme suyu depolama gibi çok çeşitli amaçları vardır. Ancak inşaat veya işletme aşamalarında meydana gelebilecek aksaklıklar baraj yıkılmalarına sebep olmaktadır. Baraj yıkılmalarının çevresel ve ekonomik etkilerinin yanında, yıkılma sonucunda çok ciddi can kayıpları da meydana gelmektedir. Oluşabilecek kayıpları azaltmanın en etkili yolu baraj yıkılma süresinin hesaplanması ve erken uyarı sistemlerinin kullanılmasıdır. Baraj güvenliği için risk, barajda herhangi bir aksaklığın meydana gelme olasılığının sayısal olarak ifade edilmesidir. Özellikle ekonomik yetersizlikler sebebiyle tüm barajlara eşit kaynak aktarılması ve yüksek maliyet gerektirecek incelemeler gerçekleştirilmesi zordur. Bu sebeple baraj risk değerlendirmeleri yapılarak öncelikle yüksek risk değerine sahip ve yıkılma durumunda çevresinde yaşayan insanları tehdit etme olasılığı en yüksek barajlar belirlenerek bu barajlar üzerinde detaylı araştırmalar yapılmalıdır. Bu çalışmanın amacı Türkiye’den seçilen bir baraj üzerinde yıkılma parametrelerini belirleyerek, bu barajın risk değerlendirmesini yapmaktır. Risk analizi için Utah Üniversitesi tarafından Federal Emergency Management Agency’nin (FEMA) kullanımı için hazırlanmış olan EXCEL tabanlı risk analizi yazılımı (FEMA Risk Tool) kullanılmıştır. İncelenen barajın risk analizi sonuçlarına göre; borulanma durumu için risk değerinin yüksek olduğu görülmüş ve alınabilecek önlemler açıklanmıştır. Geliştirilen yazılım, barajların hızlı ve etkili bir şekilde sıralanmasına olanak sağladığı için çok sayıdaki baraj üzerinde kısa sürede uygulanabilmektedir.,People's water needs are increasing in direct proportion along with the rapid increase in world population. Advances in civil engineering are intended to allow building higher dams and to store water in dam reservoirs much more than past years. Dams have different purposes such as irrigation, hydropower, flood control and drinking water storage. Errors during construction and operation periods of dams could cause dam failures. The effects of dam failures could be environmental and economic as well as failures could cause loss of life. Calculating dam failure time and using early warning systems could prevent loss of life and property damages. Risk in dam safety means, numerical probability of misoperation of any dam part. Because of economical deficiencies, it is hard to pay equal attention or to make high cost detailed examinations for all dams. For this reason risk assessment must be performed for all dams and detailed research could be made for dams that have high risk value or dams that could threat population living near dam. The aim of this study is to clarify dam failure modes and to make risk analysis of a dam from Turkey. For this purpose, an Excel based risk analysis tool was used. This tool was created by UTAH State University for the use of Federal Emergency Management Agency (FEMA). Results of risk analysis showed that piping failure risk value is high for embankment dams and recommended actions for this failure mode is explained. This software helps to sort dams effectively and fast. So it can be applied many dams in a short time.
  • [ X ]
    Öğe
    Versions of the drainage area ratio method for transfer of daily or monthly stream flows
    (Emerald Group Publishing Ltd, 2023) HaktanIr, Tefaruk; Aydemir, Alper; Acanal, Nese
    By the drainage-area ratio method, the daily or monthly flows gauged at a nearby station are transferred to an ungauged section where a dam is to be built by multiplying them by the real number resulting from raising the ratio of the drainage areas of the dam section and of the station to an exponent (n). Commonly n is taken as 1. First, using the daily flows of two stations nearby the dam section on the same stream or on a neighboring stream, having a common N-year long gauging record, it is proposed that 365 linear regressions be fitted to N pairs of 365 daily flows, and relating them to the drainage area ratios, daily flows at the dam section be computed using 365 n's each belonging to a day. Next, by the same analytical model applied to the monthly flows, 12 monthly flows are transferred to the dam section. Five versions of the drainage-area ratio method, three of which with constant exponents, are investigated, and the last one with n = 1 is found to be relatively the worst.