Hasil Pencarian  ::  Simpan CSV :: Kembali

"Optical flow visualization adalah metode visualisasi aliran yang memanfaatkan perbedaan indeks refraksi cahaya untuk melihat gangguan pada media transparan. Salah satu teknik yang menggunakan metode ini adalah teknik schlieren, dalam teknik ini susunan optik paling sederhana yang dapat di implementasikan adalah single mirror off-axis schlieren system. Namun dalam susunan optik ini penggunaan cermin spherical berjarak fokus kurang dari satu meter yang terbuat dari bahan akrilik sangatlah kurang, khususnya pada penelitian ilmiah. Penelitian ini akan berfokus pada single mirror off-axis schlieren system dengan menggunakan spherical mirror yang memiliki diameter sebesar 600 mm dan jarak fokus 584,2 mm. Objek yang diamati akan divariasikan berdasarkan perbedaan densitas antara udara disekitar objek dengan udara atmosfir. Pada penelitian ini akan diamati effective field-of-view yang didapatkan serta kontras gambar yang dihasilkan dan hubungannya dengan ISO kamera yang digunakan. Field-of-view efektif yang dihasilkan bergantung pada geometri dan kualitas permukaan cermin yang digunakan. Kontras gambar tertinggi didapatkan dari efek schlieren yang dihasilkan karena pencampuran gas dengan densitas yang berbeda, khusunya butane gas, sementara kontras gambar terendah didapatkan dari efek schlieren yang diakibatkan perubahan temperatur pada udara. Pengaturan ISO kamera yang digunakan bergantung dengan jenis fenomena yang diamati.

---

Optical flow visualization is a method that utilizes refractive index gradient for seeing the disturbance of air in transparent media. The technique that uses this method is the schlieren technique, the simplest optical arrangement in this technique is single mirror off-axis schlieren system. However, usage of short focal length spherical mirror made by acrylic in this optical arrangement is still lacking, especially in the scientific research. This research will focus on a single mirror off-axis schlieren system using a spherical mirror with 600 mm diameter and 584.2 mm focal length. The observed object will be varied based on the density difference between the air around it and the atmospheric air. In this study, the effective field-of-view obtained will be observed as well as the resulting image contrast and its relationship with the camera’s ISO. The resulting effective field-of-view depends on the geometry and surface mirror quality. The highest image contrast is obtained from the Schlieren effect which caused by mixing different densities gases, especially for butane gas, while the lowest image contrast is obtained from the Schlieren effect caused by temperature changes in the air. The recommended camera’s ISO depends on the type of phenomenon being observed."

"Water tunnel merupakan salah satu alat yang digunakan untuk melakukan penelitian mengenai fenomena-fenomena dinamika fluida. Salah satu keunggulan dari water tunnel adalah dapat menampilkan visualisasi aliran yang lebih jelas. Water tunnel ini merupakan alat praktikum di Departemen Teknik Mesin Universitas Indonesia. Untuk mempelajari bermacam-macam fenomena mekanika fluida yang terjadi, kita harus memiliki berbagai macam profil benda uji/spesimen yang akan diamati. Untuk itu dibuatlah perangkat alat yang dapat memegang benda uji tersebut secara stabil dan kuat, serta dapat mengakomodasi berbagai bentuk profil yang hendak diamati serta pergerakan atau posisinya. Pemegang benda uji/spesimen ini dapat beroperasi didalam air, dapat mengerakan spesimen maju-mundur sebesar 250[mm] dengan kelipatan 50[mm], dapat mengerakkan spesimen naik-turun sebesar 50[mm],dan dapat mengakomodasi pergerakan berputar spesimen pada titik beratnya. Dengan bekerja sama dengan saudara robert, menggunakan metode visualisasi aliran yaitu dye injection untuk melihat visualisasi aliran yang terjadi. Karakteristik force balance yaitu drag force untuk prototype silinder berdiameter 1,5? didapatkan, dengan mengunakan beberapa asumsi untuk mendapatkan tekanan pada permukaan silinder.

---

Water tunnel is one of research tool for studying about fluid dynamic phenomenon. One of the advantages of using water tunnel is its can give better flow visualization. This water tunnel is an experimental tool for Mechanical Engineering Department, University of Indonesia. To studying all kind of fluid dynamic that occurring, we must provide several profile specimen which can be observed. For that constructed model support system which able to hold the specimen stable and strong, and also able to accommodate any profile we want to observe including its movement and positioning. The model support system able to operate under water, its can move specimen forward and backward for 250[mm] for every 50[mm], its can move specimen up and down for 50[mm], and its can accommodate specimen revolution on its weight point. By cooperate with Robert; using flow visualization method is dye injection to observe flow visualization that occurred. Force balanced characteristic which is drag force for prototype cylinder with diameter 1.5? is occupied, by using few assumption to get pressure at cylinder surface."

"A powerful flow visualization based on a laser-sheet and the quantification of the intensity of the lightfrom Mie scattering had been introduced and successfully used to evaluate the statistics and spatialcorrelations of gas distribution injected into a two-dimensional turbulent recirculation airflow, utilizing abackstep configuration. In the experiment the free stream velocity was, U, = 10 m/s and the step heightwas, H = 20 mm. The study focussed on the _fluctuation and the gas distribution in the recirculation zonein order to elucidate the gas-air moving characteristics. The results show that the distribution of injectedgas shows different trends depending on the location of injection. When the specific momentum ofinjection is increased the maximum fluctuation level of the gas concentration decreases. A reduction upto 30 % of the maximum RMS value of luminance intensity _fluctuation can be observed when increasingspecific momentum ratio of injection from 0. 04 to 0.3. Spatial correlations suggested that mixing betweeninjected gas and surrounding air was more rapid and better in case injection in the near reattachmentpoint due to higher turbulence in the region."

"This is the first volume of a two volume set which presents the results of the 31st International Symposium on Shock Waves (ISSW31), held in Nagoya, Japan in 2017. It was organized with support from the International Shock Wave Institute (ISWI), Shock Wave Research Society of Japan, School of Engineering of Nagoya University, and other societies, organizations, governments and industry. The ISSW31 focused on the following areas: Blast waves, chemical reacting flows, chemical kinetics, detonation and combustion, ignition, facilities, diagnostics, flow visualization, spectroscopy, numerical methods, shock waves in rarefied flows, shock waves in dense gases, shock waves in liquids, shock waves in solids, impact and compaction, supersonic jet, multiphase flow, plasmas, magnetohyrdrodynamics, propulsion, shock waves in internal flows, pseudo-shock wave and shock train, nozzle flow, re-entry gasdynamics, shock waves in space, Richtmyer-Meshkov instability, shock/boundary layer interaction, shock/vortex interaction, shock wave reflection/interaction, shock wave interaction with dusty media, shock wave interaction with granular media, shock wave interaction with porous media, shock wave interaction with obstacles, supersonic and hypersonic flows, sonic boom, shock wave focusing, safety against shock loading, shock waves for material processing, shock-like phenomena, and shock wave education. These proceedings contain the papers presented at the symposium and serve as a reference for the participants of the ISSW 31 and individuals interested in these fields."

"This is the second volume of a two volume set which presents the results of the 31st International Symposium on Shock Waves (ISSW31), held in Nagoya, Japan in 2017. It was organized with support from the International Shock Wave Institute (ISWI), Shock Wave Research Society of Japan, School of Engineering of Nagoya University, and other societies, organizations, governments and industry. The ISSW31 focused on the following areas: Blast waves, chemical reacting flows, chemical kinetics, detonation and combustion, ignition, facilities, diagnostics, flow visualization, spectroscopy, numerical methods, shock waves in rarefied flows, shock waves in dense gases, shock waves in liquids, shock waves in solids, impact and compaction, supersonic jet, multiphase flow, plasmas, magnetohyrdrodynamics, propulsion, shock waves in internal flows, pseudo-shock wave and shock train, nozzle flow, re-entry gasdynamics, shock waves in space, Richtmyer-Meshkov instability, shock/boundary layer interaction, shock/vortex interaction, shock wave reflection/interaction, shock wave interaction with dusty media, shock wave interaction with granular media, shock wave interaction with porous media, shock wave interaction with obstacles, supersonic and hypersonic flows, sonic boom, shock wave focusing, safety against shock loading, shock waves for material processing, shock-like phenomena, and shock wave education. These proceedings contain the papers presented at the symposium and serve as a reference for the participants of the ISSW 31 and individuals interested in these fields.Chapter “Effects of Liquid Impurity on Laser-Induced Gas Breakdown in Quiescent Gas: Experimental and Numerical Investigations” is available open access under a Creative Commons Attribution 4.0 International License at link.springer.com."