Visualization of boundary-layer development on turbomachine blades with liquid crystals

This report documents a study of the use of liquid crystals to visualize boundary layer development on a turbomachine blade. A turbine blade model in a linear cascade of blades was used for the tests involved. Details of the boundary layer development on the suction surface of the turbine blade model were known from previous research. Temperature sensitive and shear sensitive liquid crystals were tried as visual agents. The temperature sensitive crystals were very effective in their ability to display the location of boundary layer flow separation and reattachment. Visualization of natural transition from laminar to turbulent boundary layer flow with the temperature sensitive crystals was possible but subtle. The visualization of separated flow reattachment with the shear sensitive crystals was easily accomplished when the crystals were allowed to make a transition from the focal-conic to a Grandjean texture. Visualization of flow reattachment based on the selective reflection properties of shear sensitive crystals was achieved only marginally because of the larger surface shear stress and shear stress gradient levels required for more dramatic color differences

SOME RESULTS OF NASA-IOWA STATE UNIVERSITY RESEARCH ON AXIAL-FLOW PUMPS

INTRODUCTION This paper is a commentary on a small chapter in the recent history of turbomachinery research. It was written to describe the positive influence of an individual, Melvin J. Hartmann, working in a federal research center, on a particular university research program. However, in its final form, it cannot help but shed some light on the longterm effects of small-scale mission-oriented, federal agency funding of engineering research in universities. Secondarily, it will recall a series of experimental investigations of axial-flow pump configurations which produced data of possible relevance to current compressor and pump problems

Flow Through a Rectangular-to-Semiannular Diffusing Transition Duct

Rectangular-to-semiannular diffusing transition ducts are critical inlet components on supersonic airplanes having bifucated engine inlets. This paper documents measured details of the flow through a rectangular-to-semiannular transition duct having an expansion area ratio of 1.53. Three-dimensional velocity vectors and total pressures at the exit plane of the diffuser are presented. Surface oil-flow visualization and surface static pressure data are shown. The tests were conducted with an inlet Mach number of 0.786 and a Reynolds number based on the inlet centerline velocity and exit diameter of 3.2 x 10(exp 6). The measured data are compared with previously published computational results. The ability of vortex generators to reduce circumferential total pressure distortion is demonstrated

Study of compressible flow through a rectangular-to-semiannular transition duct

Detailed flow field measurements are presented for compressible flow through a diffusing rectangular-to-semiannular transition duct. Comparisons are made with published computational results for flow through the duct. Three-dimensional velocity vectors and total pressures were measured at the exit plane of the diffuser model. The inlet flow was also measured. These measurements are made using calibrated five-hole probes. Surface oil flow visualization and surface static pressure data were also taken. The study was conducted with an inlet Mach number of 0.786. The diffuser Reynolds based on the inlet centerline velocity and the exit diameter of the diffuser was 3,200,000. Comparison of the measured data with previously published computational results are made. Data demonstrating the ability of vortex generators to reduce flow separation and circumferential distortion is also presented

PENGARUH METODE EKSPERIMEN DAN METODE DEMONSTRASI TERHADAP PRESTASI BELAJAR FISIKA POKOK BAHASAN LISTRIK DINAMIS

Penelitian ini secara deskriptif bertujuan untuk mengetahui kecendrungan prestasi belajar fisika pokok bahasan listrik dinamis yang diajar menggunakan metode Eksperimen, metode demonstrasi dan metode pembelajaran Konvebsional. Secara komparatif untuk mengetahui perbedaan prestasi belajar fisika pokok bahasan listrik dinamis antara yang diajar menggunakan metode Eksperimen, metode Demonstrasi dan metode Konvensional. Jenis penelitian ini adalah Quasi Eksperimen. Populasi dalam penelitian adalah seluruh siswa kelas X yang terdiri dari 7 kelas sejumlah 217 siswa. Sampel diambil dengan teknik random sampling. Kemampuan awal diperoleh dari nilai pre-test. Data prestasi hasil belajar dikumpulkan dengan tes pilihan ganda. Teknik analisis data dengan menggunakan uji Anava satu jalur, setelah dilakukan uji persyaratan yang meliputi uji normalitas sebaran dan uji homogenitas varian. Hasil penelitian menunjukkan bahwa ada perbedaan yang sangat signifikan prestasi belajar fisika antara yang diajar menggunakan metode Eksperimen, metode Demonstrasi dan yang diajar menggunakan metode Konvebsional

Accuracy of Numerical Simulations of Tip Clearance Flow in Transonic Compressor Rotors Improved Dramatically

The tip clearance flows of transonic compressor rotors have a significant impact on rotor and stage performance. Although numerical simulations of these flows are quite sophisticated, they are seldom verified through rigorous comparisons of numerical and measured data because, in high-speed machines, measurements acquired in sufficient detail to be useful are rare. Researchers at the NASA Glenn Research Center at Lewis Field compared measured tip clearance flow details (e.g., trajectory and radial extent) of the NASA Rotor 35 with results obtained from a numerical simulation. Previous investigations had focused on capturing the detailed development of the jetlike flow leaking through the clearance gap between the rotating blade tip and the stationary compressor shroud. However, we discovered that the simulation accuracy depends primarily on capturing the detailed development of a wall-bounded shear layer formed by the relative motion between the leakage jet and the shroud

Fluid mechanics SI version

xix, 745[10] hlm.: 25 c

Mekanika Fluida Jilid 2+ CD

Buku Mekanika Fluida yang luar biasa ini menyajikan penerapan mekanika fluida dalam kehidupan sehari-hari. Dibanding dengan buku-buku pesaingnya buku ini memiliki contoh soal paling banyak. Setiap contoh soal tersebut bukan saja dianalisis masalahnya untuk kemudian disajikan penyelesaiannya secara tuntas akan tetapi disajikan juga diskusi singkat mengenai prinsip-prinsip yang relevan dari kehidupan sehari-hari.xv + 480 hlm; 17.5 x 25 Cm

Mekanika Fluida Jilid 1

xvi+548hlm;25c