Kemal B. Yuceil

Kemal B. Yuceil
Istanbul Technical University · Department of Astronautical Engineering

Ph.D.

About

36
Publications
2,401
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815
Citations

Publications

Publications (36)
Chapter
A supersonic aircraft is designed to exceed the speed of sound in its normal flight configurations. Supersonic aircrafts are affected by shock waves which are prime importance in air intakes whose purpose is to provide a stable, uniform, low-loss, subsonic flow to the engine face at all flight conditions. Oblique shock waves are an efficient form o...
Article
Velocity measurements were made in the near field of underexpanded sonic air jets using particle image velocimetry (PIV), interferometric Rayleigh scattering and total pressure tubes. Shadowgraph technique was also used to visualize the shock waves generated due to underexpansion in the near field of the jets. The two main objectives were to study...
Article
The capability for CFD prediction of hypersonic shock wave laminar boundary layer interaction was assessed for a double wedge model at Mach 7.1 in air and nitrogen at 2.1. MJ/kg and 8. MJ/kg. Simulations were performed by seven research organizations encompassing both Navier-Stokes and Direct Simulation Monte Carlo (DSMC) methods as part of the NAT...
Conference Paper
Flow visualization experiments and fluctuating pressure measurements were conducted in supersonic internal compression inlet models in a Mach 2 flow. In the first phase of the study, the inlet model consisted of a single sharp-edged shock generator on the upper lip of the inlet. In the second phase, another ramp was added to the floor at the entran...
Conference Paper
The subject of this research is to investigate experimentally the interaction between the shock-wave and boundary layer induced by sharp fins. All experiments have been done for Mach 2 and were performed in the 15x15 cm Trisonic Wind Tunnel located at the Trisonic Research Laboratory (TAL) of Istanbul Technical University. Since the test section ha...
Conference Paper
To investigate the influence of boundary layer on the supersonic internal compression inlet, flow visualization experiments and fluctuating pressure measurements were conducted in an internal compression inlet model with sharp-edged shock generators in a Mach 2.15 flow. In the first phase of the study, the inlet model was mounted on the test sectio...
Conference Paper
Flow visualization experiments and fluctuating pressure measurements were conducted in supersonic internal compression inlet models in a Mach 2 flow. In the first phase of the study, the inlet model consisted of a single sharp-edged shock generator on the upper lip of the inlet. In the second phase, another ramp was added to the floor at the entran...
Article
An experimental study was conducted to investigate the effects of ramp-type vortex generators in a Wheeler doublet configuration (WDs), vortex generator jets (VGJs), and their combination on supersonic inlet unstart, and to achieve active control of inlet unstart. Actuators were placed on the inner side walls of a floor-mounted inlet-isolator model...
Conference Paper
Fluctuating pressure measurements are performed as a preliminary effort to investigate the shock wave boundary layer interaction in a supersonic inlet model at Mach 2. Experiments are carried out in the 15x15 cm Trisonic Wind Tunnel located at the Istanbul Technical University. A supersonic inlet model with a sharp-edged shock generator (a 12-degre...
Conference Paper
Full-text available
Understanding the physical mechanisms and having insight to the complex flowfield involving unstart phenomena in supersonic inlets has gained considerable attention especially in the area of scramjet inlet/isolator aerothermodynamics. In this study, Schlieren visualization and computational analysis of shock wave structures in ramjet/scramjet inlet...
Article
Understanding the physical mechanisms and having insight to the complex flowfield involving unstart phenomena in supersonic inlets has gained considerable attention especially in the area of scramjet inlet/isolator aerothermodynamics. In this study, Schlieren visualization and computational analysis of shock wave structures in ramjet/scramjet inlet...
Article
The dynamics of unstart in a floor-mounted inlet-isolator model in a Mach 5 flow are investigated experimentally using particle image velocimetry and fast-response wall pressure measurements. The inlet compression is obtained with a 6-deg ramp and the isolator is a rectangular straight duct that is 25.4 nun high by 50.8 min wide by 242.3 nun long....
Conference Paper
An experimental study was conducted to investigate the effects of Wheeler Doublets (WDs), Vortex Generator Jets (VGJs), and their combination on supersonic inlet unstart. The final objective of the investigation was to achieve active control of unstart through the use of an unstart detection technique and the most effective of these actuators. Actu...
Conference Paper
The dynamics of unstart and unstarted flows in a floor-mounted inlet-isolator model in a Mach 5 flow are investigated experimentally using PIV, fast response wall pressures and 8 kHz schlieren imaging. The inlet compression is obtained with a 6-degree ramp and the isolator is a rectangular straight duct that is 25.4 mm high by 50.8 mm wide by 242.3...
Article
The dynamics of unstart of a floor-mounted inlet/isolator model in a Mach 5 flow are investigated experimentally. The inlet section contains a 6-deg compression ramp, and the isolator is a rectangular straight duct that is 25.4-mm high by 50.8-mm wide by 242.3-mm long. Measurements made include 8-kHz schlieren imaging and simultaneous fast-response...
Article
The dynamics of the unstart process in an inlet/isolator model mounted to the floor of a Mach 5 wind tunnel are investigated using PIV, high-speed (8 kHz) schlieren imaging and fast-response surface pressure measurements. The inlet section contains a 6-degree compression ramp and the isolator is a rectangular straight duct that is 25.4 mm high by 5...
Article
Condensation fog planar laser scattering has been used to visualize the structure of supersonic turbulent shear flows. Some previous work at Princeton in a supersonic boundary layer has suggested that the scattering from CO2 clusters closely reflects the fluctuating density field. However, the relationship between the fog scattering and the velocit...
Conference Paper
Velocity measurements were made in the near field of underexpanded sonic air jets using particle image velocimetry (PIV), interferometric Rayleigh scattering and total pressure tubes. The two main objectives were to study the effect of underexpansion ratio on the flow structure and to determine the suitability of the PIV technique in high-speed flo...
Article
Full-text available
An analysis and experiments were carried out to study the spreading and centerline property decay rates of underexpanded supersonic jets. The main purpose was to determine a suitable set of normalization parameters that would account for the initial expansion process and allow for a comparison of the asymptotic mixing rates of jets within a large r...
Article
Full-text available
The velocity field of underexpanded sonic air jets were investigated using digital particle image velocimetry (PIV). The jets were produced by a convergent nozzle connected to a settling chamber. Measurements were made for five different underexpanded jets with chamber-to-ambient pressure ratios of Po/Pa=1.89, 4.77, 14.26, 29.36 and 38.41 (which co...
Article
Experiments have been made to determine if the unsteady now induced by a streamwise cavity in the nose of a blunt body can reduce mean surface heat transfer rates compared to the same body without a cavity, Measurements were made at Mach 5 and included surface temperatures obtained using an infrared camera, fluctuating pressures at the cavity base,...
Article
Hypersonic flow over the nose of a blunt body with a forward-facing cavity is studied both experimentally (Mach 5 blowdown tunnel) and numerically (commercial finite volume code). Trends are established for the pressure oscillations within the cavity, flowfield structure, and surface heating for different cavity depths and lip radii. Resonant press...
Article
Surface temperatures on a hemisphere-cylinder body with a nose cavity in a Mach 4.9 airflow have been measured using an infrared camera, Fluctuating surface pressures have also been measured at the cavity base. The cavity diameter D was fixed at one-half the cylinder diameter and the length L of the cavity was varied. If the cavity lip is sharp and...
Article
This Note describes an experimental investigation of the shock-wave/turbulent boundary-layer interaction induced by a cylindrical protuberance at Mach numbers 1.7 and 2.2. Data are presented for flow regions both upstream and downstream of the cylinder. Various physical aspects of the flow are illuminated by the experimental data, which include the...

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Projects

Projects (4)
Project
Uçuş hızı Mach 2 - 4 aralığında olan dış sıkıştırmalı tipte bir hava alığı içinde ve etrafında farklı şartlarda oluşan akış yapısı, yüksek hızlı Schlieren yöntemi ile görüntülenecek ve görüntüleme ile eşzamanlı dinamik basınç ölçümleri gerçekleştirilecektir. Hava alığı difüzör bölümünün en sonuna, ölçüm sistemleri ile senkronize çalışan elektromekanik bir konik vana yerleştirilecektir. Bu vananın hareketi difüzor çıkışında ki basıncı belirleyecek ve bu sayede hava alığının çalışma rejimleri test sırasında değiştirilecektir.
Project
Bu çalışmada, TÜBİTAK UME tarafından Mach 0.5 – 0.95 hız aralığında ölçüm yapmak üzere tasarlanıp üretilen farklı geometrilere sahip Pitot-statik prob modellerinin, İTÜ Trisonik Rüzgar Tüneli’nde yapılacak akış testleriyle yine TÜBİTAK UME tarafından belirlenen akış koşulları altında karakteristikleri elde edilmiştir.
Project
Türk Havacılık ve Uzay Sanayii A.Ş. (TUSAŞ) ile İstanbul Teknik Üniversitesi arasında ortaklaşa yürütülen "Ses Üstü Hava Alıklarında Şok Dalgası Sınır Tabaka Etkileşiminin Deneysel İncelenmesi" adlı proje çalışması kapsamında Mach 1.5 – 2 aralığında uçan sesüstü bir savaş uçağının motor hava alığı ağzında oluşan şok dalgasının alık rampa yüzeyinde gelişen sınır tabaka ile etkileşimi deneysel olarak incelenmiştir. Hava alığına yaklaşan sesüstü akış alığın ön tasarım geometrisine göre belirlenmiş olan bir rampanın oluşturduğu eğik şoktan geçerek biraz yavaşlamakta, daha sonra oluşan bu eğik şokun alık üst dudağına çarpması ile yansıyarak oluşan ikinci bir dik ya da güçlü bir şok dalgasından geçerek sesaltı hızlara inmektedir. Bu noktada yansıma ile oluşan ikinci şok dalgası alık ağzı girişinde gelişen türbülanslı sınır tabaka ile etkileşmektedir. Bu etkileşimde oluşan şok dalgaları schlieren ve shadowgraph akış görünürlüğü yöntemleri ile, olası akım ayrılma çizgileri yağ akış görünürlüğü ve etkileşimin yaratmış olduğu nispeten düşük frekanslı zamana bağlı değişimler yüzeye monte edilmiş yüksek cevap hızına sahip Kulite basınç duyargalarıyla basınç ölçümü yapılarak incelenmiştir. Etkileşimin neden olduğu akım ayrılmasının etkisinin azaltılması ve ortaya çıkan dinamik basınç yüklerinin nasıl değiştiğini anlamak amacıyla etkileşim bölgesi öncesinde alık giriş yüzeyine monte edilmiş küçük ölçekli pasif girdap üreteçlerinin etkileşim üzerindeki etkileri akım görünürlüğü ve basınç ölçümleri ile incelenmiştir.