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All Journal Jurnal Kependidikan: Penelitian Inovasi Pembelajaran JIPF (Jurnal Ilmu Pendidikan Fisika) Jurnal Penelitian Pendidikan IPA (JPPIPA) INDONESIAN JOURNAL OF APPLIED PHYSICS COMPTON: Jurnal Ilmiah Pendidikan Fisika Jurnal Fisika Indonesia Wahana Fisika : Jurnal Fisika dan Terapannya Jurnal Pendidikan MIPA
Restu Widiatmono
Physics Study Program Universitas Negeri Yogyakarta, Yogyakarta
Agriculture, Biological Sciences & Forestry Astronomy Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Decision Sciences, Operations Research & Management Earth & Planetary Sciences Education Energy Engineering Materials Science & Nanotechnology Physics

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Journal : INDONESIAN JOURNAL OF APPLIED PHYSICS

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Compressibility Effects on Turbulent Heat Transfer of Natural Convection in a Square Cavity Rida Siti Nur'aini Mahmudah; Restu Widiatmono; Denny Darmawan
INDONESIAN JOURNAL OF APPLIED PHYSICS Vol 13, No 2 (2023): IJAP Volume 13 ISSUE 02 YEAR 2023
Publisher : Department of Physics, Sebelas Maret University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/ijap.v13i2.75790

Abstract

Heat transfer in turbulent flows is one of the essential topics in power plants and thermal-based engineering. This study aims to analyze the effects of density changes due to heat transfer in a turbulent environment—which is usually neglected because it can cause instability in a simulation. We simulate an available experimental case of turbulent heat transfer of air with OpenFOAM: one with an incompressible approach (no density change) and another with a compressible treatment. The simulation geometry is a 0.75 × 0.75 m2 square cavity, where its left and right walls are kept at a temperature difference of 40 K. We compare and analyze the temperature, velocity, and turbulence kinetic energy profiles of both simulation results against the experimental data. We found that from all qualitative and quantitative comparisons, the change in density plays a vital role in turbulent heat transfer. The compressible treatment gives better results than the incompressible: the neglection of density change causes a significant difference with the experimental data. Thus, we strongly recommended incorporating compressibility in simulating heat transfer in turbulent flows.
Pembangkitan Terahertz pada Metamaterial Chiral Menggunakan Spektroskopi Emisi Terahertz Juliasih Partini; Restu Widiatmono
INDONESIAN JOURNAL OF APPLIED PHYSICS Vol 9, No 02 (2019): October
Publisher : Department of Physics, Sebelas Maret University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (743.868 KB) | DOI: 10.13057/ijap.v9i2.32438

Abstract

Metamaterial adalah material buatan dengan indeks bias negatif dan secara simultan memiliki permitivitas elektrik dan permeabilitas magnetik bernilai negatif. Pengembangan metamaterial mengalami terobosan dengan munculnya struktur metamaterial baru yang disebut sebagai metamaterial struktur chiral sebagai sumber radiasi terahertz (THz). Pengukuran sinyal emisi THz dilakukan menggunakan sistem spektroskopi emisi terahertz dengan sistem laser Ti:Sapphire femtosekon sebagai sumber radiasi. Sampel metamaterial chiral dengan ukuran panjang 1,2 mm, lebar 0,3 mm dan kedalaman 0,3 mm susunan 300 struktur dengan arah putar kanan dan putar kiri. Kedua sampel mampu membangkitkan emisi gelombang THz dalam jangkau frekuensi 0 - 2,24 THz. Proses rektifikasi optik diperlihatkan oleh adanya pembangkitan gelombang THz pada sampel metamaterial chiral oleh laser femtosekon. Hasil eksperimen memperoleh hubungan kuadratik antara energi laser pemompa dengan amplitudo gelombang THz. Hal ini dapat disimpulkan bahwa metamaterial chiral persegi dengan kedalaman berbeda telah berhasil membangkitkan emisi gelombang THz yang terpolarisasi eliptik.
Co-Authors Arifa, Muh Fajrin Artanti, Francisca Happy Denny Darmawan Denny Darmawan Dyah Respati Suryo Sumunar Frans J. M. Harren Herman Dwi Surjono Heru Kuswanto Ilham Adi Panuntun Izza Fauzia Juliasih Partini Julien Mandon Jumadi Jumadi Kusminarto - Mitrayana - Moh Ali Joko Wasono Nasir, Muhammad Hilmi Rachmah, Diah Nur Rida Siti Nur’aini Mahmudah Sri Sumardiningsih